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GAS MASKS RUSSIAN, new and boxed, NATO filter, £39. 
CCTV SYSTEM. Low cost, outdoor, IR illumination, complete with 
cables and p.s.u. Just £22.99. Ref CCTVCAMS. 
LOW COST NIGHT VISION system, Russian handheld complete 
with infra-red illuminator, |0Om range. Runs on 2 AA batteries, just 
COBRA NIGHT VISION equipment also stocked, more info on our 
web site at 
ELECTRIC SCOOTERS 18kph, 24V motor, 6 hour charge time, 
22kg weight, max load 90kg, running time up to 1 hour, range 
15km, 8-5A motor, 24V, direct drive. Our Price £229.95. Ref 
VOICE CHANGERS Hold one of these units over your phone 
mouthpiece and you can adjust your voice using the controls on 
the unit. Battery operated, £15. Ref CC3. 
LIGHTWEIGHT DOME TENTS. 120cm x 210cm, £8. Ref TENTA. 
EMMINENCE LOUDSPEAKERS 12in. dia. 50W nom, 100W 
peak, 16 ohm impedance. Pack of 4 just £19.95. Ref SPEAK39. 
PIR SECURITY SWITCHES These brand new swivel mounting 
PIR units will switch up to 2 kilowatts. Adjustable sensitivity, light 
level and time delay (9 seconds to 10 minutes), 15m detection 
range, mains operated, waterproof. £5.99 Ref PIR1PACK or a 
pack of 5 for £22.95 Ref PIR5PACK or 10 for £39.95 Ref 
12V 12Ah SEALED LEAD-ACID BATTERIES, 100mm x 150mm 
x 95mm, 4kg. £15 each. Ref SSLB. 
Complete unit will charge 12V lead acids and maintain them with 
an automatic trickle charge. Charger on its own is £15 Ref LAC or 
charger and a 12V 12Ah battery (all fully cased) is £25 Ref ACB. 
AERIAL PHOTOGRAPHY KIT. This rocket comes with a built-in 
camera! It flies up to 500 feet (150m), turns over and takes an aerial 
photograph of the ground below. The rocket then returns with its film 
via its parachute. Takes 110 film. Supplied with everything including 
a launch pad and 3 motors (no film). £29.98 Ref Astro. 
gives step-by-step guide to building wind generators and propel- 
lors. Armed with this publication and a good local scrapyard could 
make you self-sufficient in electricity! £12. Ref LOT81. 
MAGNETIC CREDIT CARD READERS, £9.95. Cased with fly- 
leads, designed to read standard credit cards! Complete with con- 
trol electronics p.c.6. and manual covering everything you could 
want to know about what's hidden in that magnetic strip on your 
card! Just £9.95 Ref BAR31. 
77 KILO LIFT MAGNET. These Samarium magnets measure 
57mm x 20mm and have a threaded hole (5/16th UNF) in the cen- 
tre and a magnetic strength of 2-2 gauss. We have tested these on 
a steel beam running through the offices and found that they will 
take more than 170lb. (77kg) in weight before being pulled off. 
Supplied with keeper. £19.95 ea. Ref MAG77. 
HYDROGEN FUEL CELL PLANS. Loads of information on hydro- 
gen storage and production. Practical plans to build hydrogen fuel 
cell (good workshop facilities required). £8 set. Ref FCP1. 
STIRLING ENGINE PLANS. Interesting information pack covering 
all aspects of Stirling engines, pictures of home made engines 
made from an aerosol can running on a candle! £12 STIR2. 
12V OPERATED SMOKE BOMBS. Type 3 is a 12V trigger and 3 
smoke cannisters, each cannister will fill a room in a very short 
space of time! £14.99. Ref SB3. Type 2 is 20 smaller cannisters 
(suitable for mock equipment fires etc.) and 1 trigger module for 
£29. Ref SB2. Type 1 is a 12V trigger and 20 large cannisters, £49. 
Ref SB1. 
PRICE JUST £69.95. Current NATO issue standard emergency 
services unit. Used by most of the world’s military personnel. New 
and boxed. Normal retail price £400, Bull’s bargain price just 
£69.95. Ref PDRM. 
VIBRATING WATCHES, vibrate when your phone rings, £16.99. 
PULSE WATCHES, display your pulse, £16.99. 
STEPPER MOTORS. Brand new stepper motors, 4mm fixing 
holes with 47-14mm fixing centres, 20mm shaft, 6-35mm diameter, 
5V/phase, 0-7A/phase, 1-8 deg. step (200 step). Body 56mm x 
36mm. £14.99 each. Ref STEP6, pack of 4 for £49.95. 
BASIC GUIDE TO LOCKPICKING. New publication gives you an 
insight! £6, Ref LPK. 
NEW HIGH POWER MINI BUG. With a range of up to 800 metres 
and 3 days use from a PP3 this is our top selling bug! Less than 
lin. square and a 10m voice pick-up range. £28. Ref LOT102. 
IR LAMP KIT. Suitable for CCTV cameras, enables the camera to 
be used in total darkness! £6. Ref EF 138. 
INFRA-RED POWERBEAM. Handheld battery powered lamp, 4in. 
reflector, gives out powerful pure infra-red light! Perfect for CCTV 
use, nightsights, etc. £29. Ref PB1. 
Comprehensive plans with loads of info on designing systems, 
panels, control electronics etc. £7. Ref PV1. 
200 WATT INVERTERS, plugs straight into your car cigarette 
lighter socket and is fitted with a 13A socket so you can run your 
mains operated devices from your car battery. £49.95. Ref SS66. 
THE TRUTH MACHINE. Tells if someone is lying by micro tremors 
in their voice, battery operated, works in general conversation and 
on the ‘phone and TV as well! £42.49. Ref TD3. 
INFRA-RED FILM. 6in. square piece of flexible infra-red film that 
will only allow IR light through. Perfect for converting ordinary 
torches, lights, headlights etc. to infra-red output using only stan- 
dard light bulbs. Easily cut to shape. 6in. square. £15. Ref IRF2 or 
a 12in. square for £29.95. Ref IRF2A. 
SMOKE ALARMS. Mains powered, made by the famous Gent 
company, easy fit next to light fittings, power point. Pack of 5 £15, 
Ref SS23, pack of 12 £24, Ref SS24. 
CCTV CAMERAS FROM £25. Check out our web site at and 
14 WATT SOLAR PANELS. Amorphous silicon panel fitted in an 
anodised aluminium frame. Panel measures 3ft. by 1ft. with 3m 
leads for easy connection. 3ft. x 1ft. solar panel £79. Ref MAG45. 
Unframed 4 pack, 8-9W (3ft. x 1ft.) £99, Ref SOLX. 35 watts of 
solar power for just £99. 4 panels, each one 3ft. x 1ft. and pro- 
ducing 8W min., 13V. Pack of four £99, Ref SOLX. 



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NEW 12V 12in. SQUARE SOLAR PANEL. Kevlar backed, 3 watt 
output, copper strips for easy solder connections. £14.99 Ref 
15P42. Pack of four just £39.95, Ref 15P42SP. 

and D-type NiCads. £9.99, Ref UNISOL. 

12V SOLAR POWER WATER PUMP. Perfect for many 12V d.c. 
uses, from solar fountains to hydroponics! Small and compact yet 
powerful, works direct from our 10W solar panel in bright sun. Max 
HD: 17ft, max flow = 8 Lpm, 1-5A. Ref AC88. £18.99. 

SOLAR MOTORS. Tiny motors which run quite happily on voltages 
from 3V-12V d.c. Works on our 6V amorphous 6in. panels and you 
can run them from the sun! 32mm dia., 20mm thick. £1.50 each. 
MAMOD STEAM ENGINES and a full range of spare parts. Check 

both radar and laser, X, K and KA bands, speed cameras and all 
known speed detection systems. 360 degree coverage, front and 
rear waveguides, 1-1in. x 2-7in. x 4-6in., fits on visor or dash, new 
low price £99, Ref WH1630. Other models available at 

BUG DETECTORS. A new detector at a sensible price! Detects 
bugs hidden in rooms, computers etc., between 1-200MHz, 
adjustable sensitivity, 9V PP3 battery required. £29.95, Ref 

GIANT WEATHER BALLOONS made by Totex, we blew one up to 
7ft. diameter then it popped due to stones on the ground! £13.99, 

BARNET CROSSBOWS. We stock the entire range of crossbows, 
check out our web site at 

HOT AIR BALLOON KITS. Everything you need to build a 1-7m 
high, 4.5m in circum. hot air balloon, launch over a small burner or 
heater. £12.49, Ref HA1. 

CROOKES RADIOMETER. Fascinating glass bulb contains 
blades driven around by the sun, £9.99, Ref SC120B. 

GIANT TV OR PC VIEWING SCREEN. Turn your TV into a super- 
size screen, converts small screens into a super size 26in. £26.99, 
Ref SVGA2. 

RADIOSONDES. Made by Valsala, unused, they measure pres- 
sure, temperature and humidity. Model RS80, good stripper at £15, 

AIR WIND POWER MODULE. Produces nearly 400 watts of 
power from the wind, 1-14m blade, 12V d.c. output, 3 year war- 
ranty, built-in battery regulator. £549, Ref AIR1. 

WORMERIES. The ideal solution for your kitchen waste! Supplied 
complete with worms. Turn your rubbish into liquid feed! Two sizes 
available, small (ideal for 1-2 people), £25.45, Ref WM2, and a 
large one (ideal for 4 or more), £42.44, Ref WM1. 

COMPLETE WIRELESS CCTV SYSTEM. Includes monitor, cam- 
era, up to 100m range, audio and video, UK legal, complete with 
infra-red lights. £169, Ref WMS333. 

PELTIER MODULES. 56W, 40mm x 40mm, 16V, sealed edges, 
new and boxed. Supplied with 18-page Peltier design manual fea- 
turing circuit designs, design information etc. 1 module and manu- 
al is £29.99, Ref PELT1, pack of 4 modules and manual is £99.99, 
Ref PELT2. The manual on its own is £4, Ref PELTS. 

DC MOTOR. 12V d.c., general purpose model motor, 70mm x 
50mm, 12V d.c., permanent magnet, 4mm x 25mm shaft. £6, Ref 
GPM1, pack of 10 is just £40, Ref GPM2. 

180R.P.M. MAINS MOTOR. Induction type, 90mm x 70mm, 50mm 
x 5mm shaft, 12A continuous rating, thermal protected. £22, Ref 

SOLID-STATE RELAYS. P.C.B. mounting, these relays require 3V 
to 32V d.c. to operate but will switch up to 3A a.c. mains. Pack of 
4 £5, Ref SPEC1B. 

12V RELAYS. 2 x 2 c/o 16A contacts p.c.b. mount (will fit Vero), 
tray of 25 relays for just £9.95, Ref SPEC1. 

VENNER TIME CONTROLS. Designed to be wired in permanent- 
ly they will switch up to 16A 240V a.c. motorised with dial and pins. 
New and boxed. £15, Ref VTS. 

GYROSCOPES. We still sell original 1917 design, hours of fun for 
all the family, complete with stand, string, box and info. £6, Ref 

INNOVATIONS. We also sell a wide range of innovative products 
for the home, these are at 

INVERTERS. Convert 12V d.c. into 240V mains (modified sine 
wave), 300 watt (150 watt continuous), £59.95, Ref VER3. 600 
watt model (330 watt continuous), £79.95, Ref VER4. 

10 WATT SILICON SOLAR PANEL, 10 year life, waterproof, 
ora x 365mm x 26mm, 14V, 10W, 1.8kg, framed. £84.99, Ref 

STICKY LABELS. Small address labels etc. are very useful and 
can be ordered online at 

2-WAY MIRROR KIT. Contains enough material to make up to a 
500mm x 2200mm mirror (excl. glass), full instructions. £19.95, 
Ref WFO01. 

.22 AIR RIFLE. Under lever type, powerful Chinese training rifle, 
£38.26, Ref A1047. 500 pellets, £2.68, Ref A1091. 

-22 AIR RIFLE STANDARD TYPE. Chinese training rifle, on legal 
limit for air rifles, £29.75, Ref A1040. Pellets £2.68, Ref A1091. 




*phone: 01273 491490 Fax 491813 
Sales @ 

SHUT THE BOX. Check out for a range of 
pub games and magic tricks. 

have collated 140 business manuals that give you information on 
setting up different businesses, you peruse these at your leisure 
using the text editor on your PC. Also included is the certificate 
enabling you to reproduce (and sell) the manuals as much as you 
like! £14, Ref EP74. 

ANICS CO2 GAS POWERED PISTOL. Russian handheld pistol 
powered by Sparklets CO2 cylinders (give approx. 70 shots), fires 
steel BB. Pistol £58.22, Ref AGA101, tub of 1,500 BB shot £5.10, 
Ref A1015, pack of 5 CO2 cartridges £3.50, Ref GAS5. 

33 KILO LIFT MAGNET. Neodynium, 32mm diameter with a fixing 
bolt on the back for easy mounting. Each magnet will lift 33 kilos, 
4 magnets bolted to a plate will lift an incredible 132 kilos! £15, Ref 
MAG33. Pack of 4 just £39, Ref MAG33AA. 

BSA METEOR AIR RIFLE. UK made .22 rifle, top quality profes- 
sional air rifle, £84.15, Ref BSAMET 500 Lazapell pellets £5, Ref 

MAMOD 1313 TE1A TRACTION ENGINE. Attractive working 
model of traditional steam engine, £91, Ref 1313. 

MAMOD STEAM ROADSTER (white), magnificent working steam 
model car, £121, Ref 1319. 

MAMOD STEAM WAGON. Working model steam wagon finished 
in blue. £130, Ref 1318. Brown version (with barrels), £122, Ref 

POCKET SPY MONOCULAR. Clever folding monocular with 8 x 
21 magnification, made by Helios, with case. £14.99, Ref MONOC. 
CCTV SYSTEMS, £24.99. Complete with camera, 20 metres of 
cable, p.s.u. and info, simple connection to scart, £24.99. Ref 

viewed and bought online at 

bought online at 

VELOSOLEx. Traditional French style two-stroke moped (engine 
over front wheels), black only, £695, Ref VELO. Delivered direct in 
a box, you need to fit the pedals etc. then register it with your local 

HYDROPONIC GROWING SYSTEMS. Complete, everything you 
need apart from plants and light, contains grow tank, nutrients, 
pump, tester etc. GT205 710mm x 390mm, NFT system, £31.45, 
Ref GT205. GT424 1070mm x 500mm, NFT system, £58.65, Ref 

ELECTRIC BIKES, £679, Viking, built-in indicators, radio, lights, 
13mph, 5 hour charge, Shimano gears, up to 50 mile range, horn, 
26in. wheels, suspension, no licence needed, key operated, £679, 

NEBULISER, WATER ATOMISER. Ultrasonic module that you 
place in water, atomises the water into a very fine mist, many 
applications from special effects to scientific. £69, Ref NEB6. 
PORTABLE X-RAY MACHINE PLANS. Easy to construct plans 
on a simple and cheap way to build a home X-ray machine! 
Effective device, X-ray sealed assemblies, can be used for exper- 
imental purposes. Not a toy or for minors! £6/set, Ref F/XP1. 
TELEKINETIC ENHANCER PLANS. Mystify and amaze your 
friends by creating motion with no known apparent means or 
cause. Uses no electrical or mechanical connections, no special 
gimmicks yet produces positive motion and effect. Excellent for 
science projects, magic shows, part demonstrations or serious 
research and development of this strange and amazing psychic 
phenomenon. £4/set, Ref F/TKE1. 

eral ways to put subjects under your control. Included is a full vol- 
ume reference text and several construction plans that when 
assembled can produce highly effective stimuli. This material must 
be used cautiously. It is for use as entertainment at parties etc 
only, by those experienced in its use. £15/set, Ref F/EH2. 
GRAVITY GENERATOR PLANS. This unique plan demonstrates 
a simple electrical phenomena that produces an anti-gravity effect. 
You can actually build a small mock spaceship out of simple mate- 
rials and without any visible means cause it to levitate. £10/set, Ref 

up to 750,000 volts of discharge, experiment with extraordinary HV 
effects, ‘Plasma in a jar’, St Elmo’s fire, corona, excellent science 
project or conversation piece. £5/set, Ref F/BTC1/LG5. 

COPPER VAPOUR LASER PLANS. Produces 100mW of visible 
green light. High coherency and spectral quality similar to argon 
laser but easier and less costly to build, yet far more efficient. This 
particular design was developed at the Atomic Energy 
Commission of NEGEV in Israel. £10/set, Ref F/CVL1. 

VOICE SCRAMBLER PLANS. Miniature solid-state system turns 
speech sound into indecipherable noise that cannot be under- 
stood without a second matching unit. Use on telephone to prevent 
third party listening and bugging. £6/set, Ref F/VS9. 

PULSED TV JOKER PLANS. Little handheld device utilises pulse 
techniques that will completely disrupt TV picture and sound! 
Works on FM too! Discretion advised. £8/set, Ref F/TJ5. 
BODYHEAT TELESCOPE PLANS. Highly directional long 
range device uses recent technology to detect the presence of 
living bodies, warm and hot spots, heat leaks etc. Intended for 
security, law enforcement, research and development etc. 
Excellent security device or very interesting science project. 
£8/set, Ref F/BHT1. 

BURNING, CUTTING CO2 LASER PLANS. Projects an invisible 
beam of heat capable of burning and melting materials over a con- 
siderable distance. This laser is one of the most efficient, convert- 
ing 10% input power into useful output. Not only is this device a 
workhorse in welding, cutting and heat processing materials, but it 
is also a likely candidate as an effective directed energy beam 
weapon against missiles, aircraft, ground-to-ground etc. Burning 
and etching wood, cutting, plastics, textiles etc. £12/set, Ref 

MICRO SCALES. Measure 1g to 120g, 1g resolution, 80mm x 
110mm, 3 AAA batteries required. £49.94. Ref SCALEB. 
ALTERNATIVE ENERGY CD, packed with hundreds of alternative 
energy related articles, plans and information etc. £14.50. Ref 

WIRELESS DRIVEWAY ALARMS. Detect someone entering your 
driveway, 400ft. range, no wiring, will protect any entrance, uses 
built-in PIR detector. £24.99. Ref DWA. 


GOODIE PACKS. 10kg packs of clearance items, mainly suitable 
for the electronics enthusiast! Ref 10KGP. 

WHEELCHAIR MOTORS. Left and right hand, new and second- 
hand, 100s in stock. New ones £99 each, secondhand £59, 
returns £19.95. Geared, 24V, complete with electric brake. 

ISSN 0262 3617 | 

EPE Online: 

Projects and Circuits 

VOL. 31. No.9 SEPTEMBER 2002 
Cover illustration by jgr22 

An automatic flight attitude control system for your free-flight model glider 
A useful tool for testing those bargain boot sale phones before you buy! | 
EPE MORSE CODE READER by John Becker 656 

Multi-function Morse code translation and learning aid; standalone 
plus optional PC interface 

VINYL TO CD PREAMPLIFIER by Terry de Vaux-Balbirnie | 665 
Copy your old records to CD, and perhaps enhance their quality — 
in the process! | 

INGENUITY UNLIMITED hosted by Alan Winstanley 679 
Switch Mode Fan Regulator; 555 Astable 

Series and “Features 

CIRCUIT SURGERY by Alan Winstanley and lan Bell 646 
Back to Darlington; Soldering tips, types and fumes 

Quantum mechanics and Heisenberg’s Uncertainty Principle could 
impact on the architecture of future computers 

PRACTICALY SPEAKING by Robert Penfold 674 
A practical look at project construction while you are still a novice 

NET WORK - THE INTERNET PAGE surfed by Alan Winstanley 680 
Frantic about FTP?; Broadband Thermometer; LeechGet your Files 

by Terry de Vaux-Balbirnie | 
Reviewing two PIC programming aids now available via our CD-ROMs pages 

LOGIC GATE INVERTER OSCILLATORS - Part 1 by George Hylton 684 
A compendium of practical oscillator circuits for creative experimenters 

Regulars and Services 

NEWS - Barry Fox highlights technology’s leading edge : 643 
Plus: everyday news from the world of electronics 

SHOPTALK with David Barrington, 651 
The essential guide to component buying for EPE projects _ 

BACK ISSUES Did you miss these? Many now on CD-ROM! 663 
READOUT John Becker addresses general points arising 671 
A wide range of CD-ROMs for hobbyists, students and engineers 

A wide range of technical books available by mail order ? 


PCBs for EPE projects. Plus EPE project software 

©’ Wimborne Publishing Ltd 2002. Copyright in all 
drawings, photographs and articles published in ELECTRONICS MANUALS 692 
EVERYDAY PRACTICAL ELECTRONICS is fully | Essential reference works for hobbyists, students and service engineers 
protected, and reproduction or imitations in whole or 

in part are expressly forbidden. ADVERTISERS INDEX 696 
Our October 2002 issue will be published on Thursday, . +e et F , 

12 September 2002. See page 627 for details Readers Services @ Editorial and Advertisement Departments 635 

Everyday Practical Electronics, September 2002 ; 625 

Visit our website 


A bulk purchase enables us to bring to you these » 
GIANT 7-segment digital displays at a now affordable & 
price!! The 10” character size gives exceptional read- | 
ability at long distances and enables a host of applica- 
tions including, score boards, digital clocks, coun- 
ters, event timers etc. As the units are a simple 
electromechanical device and operate from 12V DC, 
simple switching via switches, relays, PIC or PC may 
be used to control single or multiple digits. Units feature “Sse 
integral ‘Zero Power memory which greatly simplifies 
desgn. For an excellent DIY practical article, see the May issue of 
‘Everyday Practical Electronics’ magazine. Ideal School / Co con- 
struction project. Supplied in good RFE condition, complete with data sheet. 

Less than 30% = Only £29.95(8) or 4 / £99.00(0) 
of makers price ! Order RW44 Order PH26 

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(o7:V 5] = 610) -7-W i] =] =a 

Converts your colour monitor into a QUALITY COLOUR TV!! 

The TELEBOX is an attractive fully cased mains powered unit, containing all 
electronics ready to plug into a host of video monitors or AV equipment which- 
are fitted with a composite video or SCART input. The composite video output 
will also plug directly into most video recorders, allowing reception of TV 
channels not normally receivable on most television receivers* (TELE- 
BOX MB). Push button controls on the front panel allow reception of 8 fully 
tuneable ‘off air UHF colour television channels. TELEBOX MB covers virtu- 
ally all television frequencies VHF and UHF including the HYPERBAND as 
used by most cable TV operators. Ideal for desktop computer video sys- 
tems & PIP (picture in picture) setups. For complete compatibility — even for 
monitors without sound — an integral 4 watt audio amplifier and low level Hi Fi 
audio output are provided as standard. Brand new — fully guaranteed. 

TELEBOX ST for composite video input type monitors £36.95 
TELEBOX STL as ST but fitted with integral speaker £39.50 
TELEBOX MB Multiband VHF/UHF/Cable/Hyperband tuner £69.95 
For overseas PAL versions state 5.5 or 6 mHz sound specification. 
*For cable / hyperband signal reception Telebox MB should be con- 
nected to a cable type service. Shipping on all Telebox's, code (B) 

State of the art PAL (UK spec) UHF TV tuner module 
 «~with composite 1V pp video & NICAM hi fi stereo sound 
© Outputs. Micro electronics all on one small PCB only 73 x 
0 x 52 mm enable full tuning control via a simple 3 wire link to 
an IBM pc type computer. Supplied complete with simple working 
program and documentation. Requires +12V & + 5V DC to operate. 

BRAND NEW - Order as MY00. Only £39.95 code (B) 

See for picture + full details 


2%" TOSHIBA MK1002MAV 1.1Gb laptop(12.5 mm H) New £59.95 
2¥2" TOSHIBA MK4313MAT 4.3Gb laptop (8.2 mm H) New£105.00 
2¥%2" TOSHIBAMK6409MAV 6.1Gb laptop (12.7 mm H) New £98.00 
2%" TOSHIBA MK1614GAV 18 Gb laptop (12 mm H) New£149.95 
2¥2" to 3¥2" conversion kit for Pc's, complete with connectors £15.95 

3%" COMPAQ 313706-B21 (IBM) 9 gb ULT/SCSI3. New £199.00 
3%" FUJI FK-309-26 20mb MFM I/F RFE £59.95 
3%" CONNER CP3024 20 mb IDE I/F (or equiv.) RFE £59.95 
3%" CONNER CP3044 40 mb IDE I/F (or equiv.) RFE £69.00 

3%" QUANTUM 40S Prodri ve 42mb SCSI I/F, New RFE £49.00 
5%" MINISCRIBE 3425 20mb MFM I/F (or equiv.) RFE £49.95 
5%" SEAGATE ST-238R 30 mb RLL I/F Refurb £69.95 
5%" CDC 94205-51 40mb HH MFM I/F RFE tested £69.95 
5%" HP 97548 850 Mb SCSI RFE tested £99.00 
5%" HP C3010 2 Gbyte SCSI differential RFE tested £195.00 
8" NEC D2246 85 Mb SMD interface. New £99.00 
8" FUJITSU M2322K 160Mb SMD I/F RFE tested £195.00 
8" FUJITSU M2392K 2 Gb SMD I/F RFE tested £345.00 

Many other floppy & H drives, IDE, SCSI. ESDI etc from stock, 
see website for full stock list. Shipping on all drives is code (C) 

MITSUBISHI FA3445ETKL 14” Ind. spec SVGA monitors £245 
FARNELL 0-60V DC @ 50 Amps, bench Power Supplies £995 
FARNELL AP3080 0-30V DC @ 80 Amps, bench Suppy £1850 
KINGSHILL CZ403/1 0-50V @ DC 200 Amps - NEW £3950 
1kW to 400 kW - 400 Hz 3 phase power sources - ex stock £POA 
IBM 8230 Type 1, Token ring base unit driver £760 
Wayne Kerr RA200 Audio frequency response analyser £2500 
INFODEC 1U, 24 port, RJ45 network patchpanels. #TH93 £49 

3COM 16670 12 Port Ethernet hub - RJ45 connectors #LD97 £69 
3COM 16671 24 Port Ethernet hub - RJ45 connectors £ 

3COM 16700 8 Port Ethernet hub - RJ45 connectors NEW £39 
IBM 53F5501 Token Ring ICS 20 port lobe modules £POA 
IBM MAU Token ring distribution panel 8228-23-5050N £45 
AIM 501 Low distortion Oscillator 9Hz to 330Khz, IEEE I/O £550 
ALLGON 8360.11805-1880 MHz hybrid power combiners £250 
Trend DSA 274 Data Analyser with G703(2M) 64 i/o £POA 
Marconi 6310 Programmable 2 to 22 GHz sweep generator £4500 
Marconi 2022C 10KHz-1GHz RF signal generator £1550 
HP1650B Logic Analyser £3750 
HP3781A Pattern generator & HP3782A Error Detector £POA 
HP6621A Dual Programmable GPIB PSU 0-7 V 160 watts £1800 
HP6264 Rack mount variable 0-20V @ 20A metered PSU £475 
HP54121A DC to 22 GHz four channel test set £POA 
HP8130A opt 020 300 MHz pulse generator, GPIB etc £7900 
HP A1, AO 8 pen HPGL high speed drum plotters - from £550 
HP DRAFTMASTER 1 8 pen high speed plotter £750 
EG+G Brookdeal 95035C Precision lock in amp £1800 
Keithley 590 CV capacitor / voltage analyser £POA 
Racal ICR40 dual 40 channel voice recorder system £3750 
Fiskers 45KVA 3 ph On Line UPS — New batteries £4500 
Emerson AP130 2.5KVA industrial spec.UPS £1499 
Mann Tally MT645 High speed line printer £2200 
Intel SBC 486/133SE Multibus 486 system. 8Mb Ram £945 


Open Mon - 




10,000,000 items EX STOCK 
For MAJOR savines 
CALL or see web site 


Legacy products 
High spec genuine multysync. 

Mitsubishi FA3415ETKL 14” SVGA Multisync colour monitor with fine 
es 0.28 dot pitch tube and resolution of 1024 x 768. A vari- 

ety of inputs allows connection to a host of computers 
__ including IBM PC's in CGA, EGA, VGA & SVGA 
~ modes, BBC, COMMODORE (including Amiga 1200), 
ARCHIMEDES and APPLE. Many features: Etched 
faceplate, text switching and LOW RADIATION MPR 
specification. Fully guaranteed, in EXCELLENT little 
used condition. Tilt & Swivel Base £4.75 
Order as 

VGA cable for IBM PC included. Only 1 29 (E) ~ cars 
Extemal cables for other types of computers available - CALL 

Generic LOW COST SVGA Monitors 

We choose the make, which includes Compaq, 
Mitsubishi, IBM, etc. Supplied ready to run with all 
cables, Standard RTB 90 day guarantee. 

14” 15° 17” 
£59.00 £69.00 £79.00 
Supplied in good used condition. Shipping code (D) 


PHILIPS HCS35 (same style as CM8833) attractively styled 14” 
colour monitor with both RGB and standard composite 15.625 
Khz video inputs via SCART socket and separate phono jacks. 
Integral audio power amp and speaker for all audio visual uses. 
Will connect direct to Amiga and Atari BBC computers. Ideal for all 
video monitoring / security applications with direct connection 
to most colour cameras. High quality with many features such as 
front concealed flap controls, VCR correction button etc. Good 

used condition - fully tested - guaranteed 
Dimensions: W14" i234" i5ye" D. Only £99.00 (E) 

PHILIPS HCS31 Ultra compact 9” colour video monitor with stan- 
dard composite 15.625 Khz video input via SCART socket. Ideal 
for all monitoring / security applications. High quality, ex-equipment 
fully tested & guaranteed (possible minor screen burns). In attrac- 
tive square black plastic case measuring W10" x H10" x 13%" D. 

240 V AC mains powered. Only £79.00 (0) 


Tiny shoebox sized industrial 40 Mhz 386 PC system measuring 
only (mm) 266 w X 88 h X 272 d. Ideal for dedicated control appli- 
cations running DOS, Linux or even Windows ! Steel case con- 
tains 85 to 265 V AC 50 / 60 hz 70 Watt PSU, a 3 slot ISA passive 
backplane and a Rocky 318 (PC104) standard, single board com- 
puter with 8 MByte NON VOLATILE solid state 'Disk On Chip' 
RAMDISK. System comprises: Rocky 318 (PC104) SBC ISA card 
with 40MHz ALi 386SX CPU, 72 pin SIMM slot with 16 Mbyte 
SIMM, AMI BIOS, battery backed up real time clock. 2 x 9 pin D 
16550 serial ports. EPP/ECP printer port, mini DIN keyboard con- 
nector, floppy port, IDE port for hard drives up to 528 MByte 
capacity, watchdog timer and PC/104 bus socket. The 8 MByte 
solid state ‘disk on a chip’ has its own BIOS, and can be fdisked, 
formatted & booted. Supplied BRAND NEW fully tested and guar- 
anteed. For full data see featured item on website. Order as QG36 

100’s of applications inc: 
firewall, routers, robotics etc Only £99.00 (D) 

Unless marked NEW, items in 
this section are pre owned. 


HP6030A 0-200V DC @ 17 Amps bench power supply £1950 
Intel SBC 486/125C08 Enhanced Multibus (MSA) New £1150 
Nikon HFX-11 (Ephiphot) exposure control unit £1450 

PHILIPS PM5518 pro. TV signal generator £1250 
Motorola VME Bus Boards & Components List. SAE / CALL £POA 

Trio 0-18 vdc linear, metered 30 amp bench PSU. New £550 
Fujitsu M3041R 600 LPM high speed band printer £1950 
Fujitsu M3041D 600 LPM printer with network interface £1250 
Siemens K4400 64Kb to 140Mb demux analyser £2950 
Perkin Elmer 299B Infrared spectrophotometer £500 
Perkin Elmer 597 Infrared spectrophotometer £3500 
VG Electronics 1035 TELETEXT Decoding Margin Meter £3250 

LightBand 60 output high spec 2u rack mount Video VDA's £495 

Sekonic SD 150H 18 channel digital Hybrid chart recorder £1995 
B&K 2633 Microphone pre amp £300 
Taylor Hobson Tallysurf amplifier / recorder £750 
ADC SS200 Carbon dioxide gas detector / monitor £1450 
BBC AM20/3 PPM Meter (Ernest Turner) + drive electronics £75 
ANRITSU 9654A Optical DC-2.5G/b waveform monitor £5650 
ANRITSU ML93A optical power meter £990 
ANRITSU Fibre optic characteristic test set £POA 
R&S FTDZ Dual sound unit £650 
R&S SBUF-E1 Vision modulator £775 
WILTRON 6630B 12.4 / 20GHz RF sweep generator £5750 
TEK 2445 150 MHz 4 trace oscilloscope £1250 
TEK 2465 300 Mhz 300 MHz oscilloscope rack mount £1955 
TEK TDS380 400Mhz digital realtime + disk drive, FFT etc £2900 
TEK TDS524A 500Mhz digital realtime + colour display etc £5100 
HP3585A Opt 907 20Hz to 40 Mhz spectrum analyser £3950 

PHILIPS PW1730/10 60KV XRAY generator & accessories £POA 
VARIACS - Large range from stock - call or see our website 
CLAUDE LYONS 12A 240V single phase auto. volt. regs 
CLAUDE LYONS 100A 240/415V 3 phase auto. volt. regs 


a a geese 8 ALL MAIL TO 18 Million Items On Line Now ! 

© 8 8 eee sec50e” 8 Seccs coo | Dept oa = 35 ie Rd Secure ordering, Pictures, Information , 

° see ee ° . 8 fe ornton Hea ane Cliabal « ail At} 
beet eae eo Surrey GR? BPD | /QcO 

Fri 9.00 - 5:30 


email = admin 

Surplus always 
wanted for cash! 

LU go) of--s Me- 10 [-5-) me) Coley <me) 
oT Ure Vib aVat g- let @er-le)lal-)ioe 
enclosures and accessories. 
Over 1000 Racks from stock 


This month’s special 
33 / 42 / 47 U - High Quality 4 
All steel Rack Cabinets 

Made by Eurocraft Enclosures Ltd to the highest pos- 
sible spec, rack features all steel construction with _. 
removable side, front and back doors. Front and - 
back doors are hinged for easy access and all § 
lockable with five secure 5 lever barrel locks 
The front door is constructed of double walled 
steel with a ‘designer style’ smoked acrylic fron 
panel to enable status indicators to be seen | 
through the panel, yet remain.unobtrusive. | 
Internally the rack features fully slotted rein- || 
forced vertical fixing members to take the heavi- |= 
est of 19” rack equipment. The two movable 
vertical fixing struts (extras available) are pre § 
punched for standard ‘cage nuts’. A mains dis- 
tribution panel internally mounted to the bottom \\. 
rear, provides 8 x IEC 3 pin Euro sockets and 1x “= 
13 amp 3 pin switched utility socket. Overall ventila- 
tion is provided by fully louvered back door and. double skinned top 
section with top and side louvres. The top panel may be removed 
for fitting of integral fans to the sub plate etc. Other features 

include: fitted castors and floor levelers, prepunched utility panel at 
lower rear for cable / connector access etc. Supplied in excellent, 
slightly used condition with keys. Colour Royal blue. some grey 
available - CALL — Can be supplied in many other configurations. 


33U 47U 

Undoubtedly a miracle of modern technology & 
our special buying power ! A quality product fea- 4 

wide angle lens gives excellent focus 
and resolution from close up to long 
range. The composite video output will 
connect to any composite monitor or TV 
oe via SCART socket) and most video 
G2 — recorders. Unit runs from 12V DC so 
| f° ideal for security & portable applica- 
- “= tions where mains power not available. 
Overall dimensions 66 mm wide x 117 deep x 43 high. Supplied 
BRAND NEW & fully guaranteed with user data, 100's of applica- 
tions including Security, Home Video, Web TV, Web Cams etc, etc. 

Order as LK33 ONLY £79.00 or 2 for £149.00 () 


NT4 WorkStation, complete with service pack 3 
and licence - OEM packaged. ONLY £89.00 is) 

ENCARTA 95 - CDROM, Not the latest - but at this price !_ £7.95 
DOS 5.0 on 32" disks with concise books c/w QBasic . £14.95 
Windows for Workgroups 3.11+ Dos 6.22 0n 3.5" disks £55.00 
Windows 95 CDROM Only - No Licence - £19.95 
Wordperfect 6 for DOS supplied on 3%" disks with manual £24.95 

shipping charges for software is code B 


Visible red, 670nm laser diode assembly. Unit runs from 5 V DC at 
approx 50 mA. Orginally made for continuous use in industrial bar- 
code scanners, the laser is mounted in a removable solid aluminium 
block, which functions as a heatsink and rigid optical mount. Dims of 
block are 50 w x 50d x 15h mm. Integral features include over tem- 
perature shutdown, current control, laser OK ouput, and gated TTL 
ON / OFF. Many uses for experimental optics, comms & lightshows 
etc. Supplied complete with data sheet. 

Order as TD91 ONLY £24.95 (a) 


Virtually every type of power supply you 
can imagine.Over 10,000 Power Supplies 
Ex Stock - Call or see our web site. 


Save ££££'s by choosing your next relay from our Massive Stocks 
covering types such as Military, Octal, Cradle, Hermetically Sealed, 
Continental, Contactors, Time Delay, Reed, Mercury Wetted, Solid 
State, Printed Circuit Mounting etc., CALL or see our web site for more information. Many obsolete types from 
stock. Save ££LL's 







_ FAX 0208 653 

All prices for UK Mainland. UK customers add 17.5% VAT to TOTAL order amount. Minimum order £10. Bona Fide account orders accepted from Govemment, Schools, 
Universities and Local Authorities - minimum account order £50. Cheques over £100 are subject to 7 worki 
(D)=£15.00, (E)=£18.00, (F)=CALL. Allow approx 3 days for shipping - faster CALL. All goods supplied to our Standard Conditions of Sale which can be viewed at our website and 
unless stated guaranteed for 90 days. All guarantees on a retum to base basis. All rights reserved to change prices / 
Discounts for volume. Top CASH prices paid for surplus goods. All trademarks, tradenames etc acknowledged. © Display Electronics 2002. E & O E.. 

days clearance. Carriage charges (A)=£3.50, (B)=£6.50, (C)=£10, 
specifications without prior notice. Orders subject to stock. 



Learn all about this fascinating aspect of electronics. It’s a growing interest around the world. 


During project construction, many hobbyists must 
have wondered if the reason their masterpiece — 
wasn’t working was due to a faulty i.c., or if the i.c. 
they’ve just removed from an old board actually 
works. The project described here provides a simple 
way to quickly test the operation of most TTL and 
CMOS digital logic i.c.s. 

A PIC16F877-20 microcontroller is used as the core 
of the circuit and is interfaced to a PC-compatible 
computer via an RS232 serial connection. Defined 
logic levels are applied to the inputs of the device 
under test and the results generated on the output 
pins are compared against those that are expected. 
The PC software has been written in Visual Basic 6 
and should run on any Microsoft 32-bit operating 
system, including Windows 98, ME, NT, 2000 and 
XP. It is supplied with profiles for a selection of 
common TTL and CMOS devices and other device 
profiles can be added. 


An entirely new induction balance design 
providing an inexpensive, easy-to-build 
locator with a good depth of penetration. 
It will find a 25mm diameter coin at up to 
240mm depth. Induction balance 
detectors can distinguish between ferrous 
and non-ferrous metals and this design is 
capable, to a large extent, of rejecting 
iron and also tin foil. The circuit uses just 
two i.c.s plus a couple of dozen other 



. at =, SS 

The game of Battleships is normally played by two 

players with pencil and paper. Its aim is for each oppo- 

nent to sink the other's fleet before their own is sunk. 
The variant of the game described here provides the 

excitement of the sea chase for just one player, who pits 

his wits against a PIC microcontroller as the other 
opponent. The position of the enemy (set by the PIC 

program!) is unknown and there are five merchant ships 
to be protected, whose positions are shown ona 5 x 7 

.e.d. matrix display. 

Some ideas for PIC-progamming experts to enhance the 

basic game are discussed in the article. 


Demand is bound to be high 


Everyday Practical Electronics, September 2002 


Our electronic kits are supplied complete with all components, high quality PCBs 
(NOT cheap Tripad strip board!) and detailed assembly/operating instructions 

@ 2 x 25W CAR BOOSTER AMPLIFIER Connects to 
the output of an existing car stereo cassette player, 
CD player or radio. Heatsinks provided. PCB 
76x75mm. 1046KT. £24.95 

No electrical connection with amplifier. Light modu- 
lation achieved via a sensitive electret microphone. 
Separate sensitivity control per channel. Power 
handing 400W/channel. PCB 54x112mm. Mains 
powered. Box provided. 6014KT £24.95 

light effect ideal for parties, discos, shop-windows & 
eye-catching signs. PCB design allows replacement 
of LEDs with 220V bulbs by inserting 3 TRIACs. 
Adjustable rotation speed & direction. PCB 
54x112mm. 1026KT £15.95; BOX (for mains opera- 
tion) 2026BX £9.00 

@ DISCO STROBE LIGHT Probably the most excit- 
ing of all light effects. Very bright strobe tube. 
Adjustable strobe frequency: 1-60Hz. Mains powered. 
PCB: 60x68mm. Box provided. 6037KT £28.95 


@ ANIMAL SOUNDS Cat, dog, chicken & cow. Ideal 
for kids farmyard toys & schools. SG10M £5.95 

@ 3 1/2 DIGIT LED PANEL METER Use for basic 
voltage/current displays or customise to measure 
temperature, light, weight, movement, sound lev- 
els, etc. with appropriate sensors (not supplied). 
Various input circuit designs provided. 3061KT 

remote control unit to switch onboard 12V/1A relay 
on/off. 3058KT £10.95 

SPEED CONTROLLER for any common DC motor up 
to 100V/5A. Pulse width modulation gives maximum 
torque at all speeds. 5-15VDC. Box provided. 3067KT 

@ 3 x 8 CHANNEL IR RELAY BOARD Control eight 12V/1A 
relays by Infra Red (IR) remote control over a 20m range in 
sunlight. 6 relays turn on only, the other 2 toggle on/off. 3 oper- 
ation ranges determined by jumpers. Transmitter case & all 
components provided. Receiver PCB 76x89mm. 3072KT 

PC serial port controlled 4-channel temperature 
meter (either deg C or F). Requires no external 
power. Allows continuous temperature data logging of 
up to four temperature sensors located 200m+ from 
motherboard/PC. Ideal use for old 386/486 comput- 
ers. Users can tailor input data stream to suit their 
purpose (dump it to a spreadsheet or write your own 
BASIC programs using the INPUT command to grab 
the readings). PCB just 38mm x 38mm. Sensors con- 
nect via four 3-pin headers. 4 header cables supplied 

but only one DS18S20 sensor. 

Kit software available free from our website. 
ORDERING: 3145KT £23.95 (kit form); 
AS3145 £29.95 (assembled); 

Additional DS18S20 sensors £4.95 each 

Create an almost infinite variety of interesting/unusu- 
al sound effects from birds chirping to sirens. 9VDC. 
PCB 54x85mm. 1045KT £8.95 

@ ROBOT VOICE EFFECT Make your voice 
sound similar to a robot or Darlek. Great fun for 
discos, school plays, theatre productions, radio 
stations & playing jokes on your friends when 
answering the phone! PCB 42x71mm. 1131KT 

@ AUDIO TO LIGHT MODULATOR Controls intensi- 
ty of one or more lights in response to an audio input. 
Safe, modern opto-coupler design. Mains voltage 
experience required. 3012KT £8.95 

@ MUSIC BOX Activated by light. Plays 8 Christmas 
songs and 5 other tunes. 3104KT £7.95 

volatile memory - no battery backup needed. 
Record/replay messages over & over. Playback as 
required to greet customers etc. Volume control & 
built-in mic. 6VDC. PCB 50x73mm. 

3131KT £12.95 

@ TRAIN SOUNDS 4 selectable sounds : whistle 
blowing, level crossing bell, ‘clickety-clack’ & 4 in 
sequence. SG01M £6.95 

Full details of all X-FACTOR PUBLICATIONS can be found in 
our catalogue. N.B. Minimum order charge for reports and plans 
is £5.00 PLUS normal P&P. 

build your own parabolic dish microphone. Listen to distant 
voices and sounds through open windows and even walls! 
Made from readily available parts. ROO2 £3.50 

@ LOCKS - How they work and how to pick them. This fact 
filled report will teach you more about locks and the art of 
lock picking than many books we have seen at 4 times the 
price. Packed with information and illustrations. R008 £3.50 

We show you how to build three different circuits for disrupt- 
ing TV picture and sound plus FM radio! May upset your 
neighbours & the authorities! DISCRETION REQUIRED. 
R017 £3.50 

building the famous Infinity Transmitter. Once installed on the 
target phone, device acts like a room bug. Just call the target 
phone & activate the unit to hear all room sounds. Great for 
home/office security! R019 £3.50 

telephone calls out of thin air! No need to wire-in a phone 
bug. Simply place this device near the phone lines to hear the 
conversations taking place! R025 £3.00 

making some cash? Well this could be just what you need! 
You get 40 reports (approx. 800 pages) on floppy disk that 
give you information on setting up different businesses. You 
also get valuable reproduction and duplication rights so that 
you can sell the manuals as you like. RO30 £7.50 


Convert any 286 upward PC into a dedicated auto- 
matic controller to independently turn on/off up to 
eight lights, motors & other devices around the 
home, office, laboratory or factory. Each relay output 
is capable of switching 250VAC/4A. A suite of DOS 
and Windows control programs are provided to- 
gether with all components (except box and PC 
cable). 12VDC. PCB 70x200mm. 3074KT £31.95 

same transmitter/receiver pair as 30A15 below plus 
the components and PCB to control two 
240VAC/10A relays (also supplied). Ultra bright 
LEDs used to indicate relay status. 3082KT £27.95 
style 300-375MHz Tx with 30m range. Receiver 
encoder module with matched decoder IC. 
Components must be built into a circuit like kit 3082 
above. 30A15 £14.95 

Simultaneously control up to 4 servo motors. Software & 
all components (except servos/control pots) supplied. 
5VDC. PCB 50x70mm. 3102KT £15.95 

5/6/8 lead motor. Fast/slow & single step rates. 
Direction control & on/off switch. Wave, 2-phase & 
half-wave step modes. 4 LED indicators. PCB 
50x65mm. 3109KT £14.95 

Control two unipolar stepper motors (3A max. each) 
via PC printer port. Wave, 2-phase & half-wave step 
modes. Software accepts 4 digital inputs from exter- 
nal switches & will single step motors. PCB fits in D- 
shell case provided. 3113KT £17.95 

Similar to kit 3093 above but uses a 12 bit Analogue- 
to-Digital Converter (ADC) with internal analogue 
multiplexor. Reads 8 single ended channels or 4 dif- 
ferential inputs or a mixture of both. Analogue inputs 
read 0-4V. Four TTL/CMOS compatible digital 
input/outputs. ADC conversion time <10uS. Software 
(C, QB & Win), extended D shell case & all compo- 
nents (except sensors & cable) provided. 3118KT 

cate fluid levels or simply the presence of fluid. Relay 
output to control a pump to add/remove water when it 
reaches a certain level. 1080KT £5.95 

@ AM RADIO KIT 1 Tuned Radio Frequency front- 
end, single chip AM radio IC & 2 stages of audio 
amplification. All components inc. speaker provid- 
ed. PCB 32x102mm. 3063KT £10.95 

@ DRILL SPEED CONTROLLER Adjust the speed 
of your electric drill according to the job at hand. 
Suitable for 240V AC mains powered drills up to 

High performance surveillance bugs. Room transmitters supplied with sensitive electret microphone & battery holder/clip. All transmit- 
ters can be received on an ordinary VHF/FM radio between 88-108MHz. Available in Kit Form (KT) or Assembled & Tested (AS). 

@ MTX - MINIATURE 3V TRANSMITTER Easy to build & guar- 
anteed to transmit 300m @ 3V. Long battery life. 3-5V operation. 
Only 45x18mm. B 3007KT £6.95 AS3007 £11.95 

MRTX - MINIATURE 9V TRANSMITTER Our best selling bug. 
Super sensitive, high power - 500m range @ 9V (over 1km with 
18V supply and better aerial). 45x19mm. 3018KT £7.95 AS3018 

HPTX - HIGH POWER TRANSMITTER High performance, 2 
Stage transmitter gives 
greater stability & higher qual- 
ity reception. 1000m range 6- 
12V DC operation. Size 
70x15mm. 3032KT £9.95 
AS3032 £18.95 

bug for its size, performance and price. Just 15x25mm. 500m 
range @ 9V. Good stability. 6-18V operation. 3051KT £8.95 
AS3051 £14.95 

when sounds detected. Low standby current. Variable trigger sen- 
sitivity. 500m range. Peaking circuit supplied for maximum RF out- 
put. On/off switch. 6V operation. Only 63x38mm. 3028KT £12.95 
AS3028 £24.95 

has its own amplifier, speaker and mic. Can be set up as either a 
hard-wired bug or two-station intercom. 10m x 2-core cable sup- 
plied. 9V operation. 3021KT £15.95 (kit form only) 

@ TRVS - TAPE RECORDER VOX SWITCH Used to automati- 
cally operate a tape recorder (not supplied) via its REMOTE sock- 
et when sounds are detected. All conversations recorded. 
Adjustable sensitivity & turn-off delay. 115x19mm. 3013KT £9.95 
AS3013 £21.95 

700W power. PCB: 48mm x 65mm. Box provided. 
6074KT £17.95 

@ 3 INPUT MONO MIXER Independent level con- 
trol for each input and separate bass/treble controls. 
Input sensitivity: 240mV. 18V DC. PCB: 60mm x 
185mm 1052KT £16.95 

Standard Cockcroft-Walton multiplier circuit. Mains 
voltage experience required. 3057KT £10.95 

@ LED DICE Classic intro to electronics & circuit 
analysis. 7 LED’s simulate dice roll, slow down & land 
on a number at random. 555 IC circuit. 3003KT £9.95 
@ STAIRWAY TO HEAVEN Tests hand-eye co-ordi- 
nation. Press switch when green segment of LED 
lights to climb the stairway - miss & start again! 
Good intro to several basic circuits. 3005KT £9.95 
@ ROULETTE LED ‘Ball’ spins round the wheel, 
slows down & drops into a slot. 10 LED’s. Good intro 
to CMOS decade counters & Op-Amps. 3006KT 

steps up a12V supply to flash a 25mm Xenon tube. 
Adjustable flash rate. 3163KT £13.95 

@ LED FLASHER 1 5 ultra bright red LED’s flash in 
7 selectable patterns. 3037MKT £5.95 

@ LED FLASHER 2 Similar to above but flash in 
sequence or randomly. Ideal for model railways. 
3052MKT £5.95 

Learn programming from scratch. Programming 
hardware, a P16F84 chip and a two-part, practical, 
hands-on tutorial series are provided. 3081KT 

@ SERIAL PIC PROGRAMMER for all 8/18/28/40 
pin DIP serial programmed PICs. Shareware soft- 
ware supplied limited to programming 256 bytes 
(registration costs £14.95). 3096KT £10.95 

@ ATMEL 89Cx051 PROGRAMMER Simple-to- 
use yet powerful programmer for the Atmel 

8901051, 89C2051 & 89C4051 uC’s. Programmer | 

does NOT require special software other than a 
terminal emulator program (built into Windows). 
Can be used with ANY computer/operating sys- 
tem. 3121KT £24.95 

expensive 9V batteries with economic 1.5V batter- 
ies. IC based circuit steps up 1 or 2 ‘AA’ batteries to 
give 9V/18mA. 3035KT £5.95 

Ideal for hobbyist & professional laboratory. Very 
reliable & versatile design at an extremely reason- 
able price. Short circuit protection. Variable DC 
voltages (3-30V). Rated output 2.5 Amps. Large 
heatsink supplied. You just supply a 24VAC/3A 

- transformer. PCB 55x112mm. Mains operation. 

1007KT £16.95. 

anywhere to phone line. Transmits only when phone is used! 
Tune-in your radio and hear both parties. 300m range. Uses line 
as aerial & power source. 20x45mm. 3016KT £8.95 AS3016 

record all conversations. Connects: between phone line & tape 
recorder (not supplied). Operates recorders with 1.5-12V battery 
systems. Powered from line. 50x33mm. 3033KT £9.95 AS3033 

PHONE BUG Place pick-up coil on the phone line or near phone 
earpiece and hear both sides of the conversation. 3055KT £11.95 
AS3055 £20.95 

@ 1 WATT FM TRANSMITTER Easy to construct. Delivers a 
Crisp, Clear signal. Two-stage circuit. Kit includes microphone and 
requires a simple open dipole aerial. 8-30VDC. PCB 42x45mm. 
1009KT £12.95 

@ 4 WATT FM TRANSMITTER Comprises three RF 
stages and an audio preamplifier stage. Piezoelectric 
microphone supplied or you can use a separate preampli- 
fier circuit. Antenna can be an open dipole or Ground 
Plane. Ideal project for those who wish to get started in the 
fascinating world of FM broadcasting and want a good 
basic circuit to experiment with. 12-18VDC. PCB 
44x146mm. 1028KT. £22.95 AS1028 £34.95 

TESTED) Four transistor based stages with Philips BLY 
88 in final stage. 15 Watts RF power on the air. 88- 
108MHz. Accepts open dipole, Ground Plane, 5/8, J, or 
YAGI antennas. 12-18VDC. PCB 70x220mm. SWS meter 
needed for alignment. 1021KT £99.95 

@ SIMILAR TO ABOVE BUT 25W Output. 1031KT £109.95 

1007 above but rated at 5Amp. Requires a 
24VAC/5A transformer. 1096KT £27.95. 

@ MOTORBIKE ALARM Uses a reliable vibration 
sensor (adjustable sensitivity) to detect movement 
of the bike to trigger the alarm & switch the output 
relay to which a siren, bikes horn, indicators or 
other warning device can be attached. Auto-reset. 
6-12VDC. PCB 57x64mm. 1011KT £11.95 Box 
2011BX £7.00 

@ CAR ALARM SYSTEM Protect your car from 
theft. Features vibration sensor, courtesy/boot light 
voltage drop sensor and bonnet/boot earth switch 
sensor. Entry/exit delays, auto-reset and adjustable 
alarm duration. 6-12V DC. PCB: 47mm x 55mm 
1019KT £11.95 Box 2019BX £8.00 

@ PIEZO SCREAMER 110cB of ear piercing noise. 
Fits in box with 2 x 35mm piezo elements built into 
their own resonant cavity. Use as an alarm siren or 
just for fun! 6-9VDC. 3015KT £10.95 

@ COMBINATION LOCK Versatile electronic lock 
comprising main circuit & separate keypad for 
remote opening of lock. Relay supplied. 3029KT 

locked detector frequency for stability & reliability. PCB 
75x40mm houses all components. 4-7m range. 
Adjustable sensitivity. Output will drive external 
relay/circuits. 9VDC. 3049KT £13.95 

@ PIR DETECTOR MODULE 3-lead assembled 
unit just 25x35mm as used in commercial burglar 
alarm systems. 3076KT £8.95 

@ INFRARED SECURITY BEAM When the invisible 
IR beam is broken a relay is tripped that can be used 
to sound a bell or alarm. 25 metre range. Mains 
rated relays provided. 12VDC operation. 3130KT 

square waves at 6 preset frequencies in factors of 10 
from 1Hz-100KHz. Visual output indicator. 5-18VDC. 
Box provided. 3111KT £8.95 

GER Analogue voltage sampler records voltages 
up to 2V or 20V over periods from milli-seconds to 
months. Can also be used as a simple digital 
scope to examine audio & other signals up to 
about 5KHz. Software & D-shell case provided. 
3112KT £18.95 

@ 20 MHz FUNCTION GENERATOR Sauare, tri- 
angular and sine waveform up to 20MHz over 3 
ranges using ‘coarse’ and ‘fine’ frequency adjust- 
ment controls. Adjustable output from 0-2V p-p. A 
TTL output is also provided for connection to a 
frequency meter. Uses MAX038 IC. Plastic case 
with printed front/rear panels & all components 
provided. 7-12VAC. 3101KT £69.95 

Great introduction to electronics. Ideal for the budding electron- 
ics expert! Build a radio, burglar alarm, water detector, morse 

code practice circuit, simple computer circuits, and much more! 
NO soldering, tools or previous electronics knowledge required. 

Circuits can be built and unassembled repeatedly. 

Comprehensive 68-page manual with explanations, schematics 
and assembly diagrams. Suitable for age 10+. Excellent for 

schools. Requires 2 x AA batteries. 

Order Code EPLO30 ONLY £14.95 (phone for bulk discounts). 

130, 300 and 500-in-ONE also available. 

628 Everyday Practical Electronics, September 2002 

LV VAV VAY Y Ae @ TU FE -F— 7 ood —8 Coy d reo) ai fot-Peoteo) aa 

- and high quality DSPTH board. Also 



Enhanced ‘PICALL ISP PIC iis! SboMledene 

Kit will program virtually ALL 8 to 40 pin* 
serial and parallel programmed PIC micro- 
controllers. Connects to PC parallel port. 
SAS with fully functional pre- 
egistered PICALL DOS and WINDOWS 
AVR software packages, all components 

programs certain ATMEL AVR, SCENIX 

SX and EEPOM 24C devices. New devices can be added to the 
software as they are released. Blank chip auto detect feature for super- 
fast bulk programming. Hardware now supports ISP programming. 

*A 40 pin wide ZIF socket is required to program 0-3in. devices (Order 
Code AZIF40 @ £15.00). 

| 3144KT_ _—| Enhanced ‘PICALLISP PIC Programmer _—'|_ £59.95 
Assembled Enhanced ‘PICALL ISP 
PIC Programmer | £64.95 
Assembled Enhanced ‘PICALL ISP PIC 
Programmer c/w ZIF socket 

ATMEL AVR Programmer 

_ Powerful programmer for Atmel 
| AT90Sxxxx (AVR) micro controller fam- 
ily. All fuse and lock bits are program- 
= mable. Connects to serial port. Can be 
# used with ANY computer and operat- 
_ ing system. Two LEDs to indicate pro- 
gramming status. Supports 20-pin DIP 
AT90S1200 & AT90S2313 and 40-pin 
DIP AT90S4414 & AT90S8515 devices. NO special software 
required — uses any terminal emulator program (built into 
Windows). The programmer is supported by BASCOM-AVR Basic 
Compiler software (see website for details). 

ATMEL AVR Programmer ~ | £2495 | 
| AS3122.—s|_ Assembled 3122 £34.95 

Atmel 89Cx051 and 89xxx programmers also available. 

PC Data Acquisition & Control Unit 

With this kit you can use a PC 
parallel port as a real world 
interface. Unit can be connected to a 
mixture of analogue and digital 
inputs from pressure, temperature, 
movement, sound, light intensity, 
weight sensors, etc. (not supplied) to 
sensing switch and relay states. It 
can then process the input data and 
use the information to control up to 11 physical devices such as 
motors, sirens, other relays, servo motors & two-stepper motors. 


@ 8 Digital Outputs: Open collector, 500mA, 33V max. 

@ 16 Digital Inputs: 20V max. Protection 1K in series, 5-1V Zener to 
_ ground. 

@ 11 Analogue Inputs: 0-5V, 10 bit (6mV/step.) 

@ 1 Analogue Output: 0-2-5V or 0-10V. 8 bit (20mV/step.) 

All components provided including a plastic case (140mm x 110mm x 
35mm) with pre-punched and silk screened front/rear panels to give a 
professional and attractive finish (see photo) with screen printed front 
& rear panels supplied. Software utilities & programming examples 

| 3093KT_ _| PC Data Acquisition & Control Unit £99.95 

| AS30938 Assembled 3093 

See opposite page for ordering 
information on these kits 

Everyday Practical Electronics, September 2002 



ABC Mini ‘Hotchip’ Board 

Currently learning about 
microcontrollers? Need to do 
something more than flash a LED 
or sound a buzzer? The ABC Mini 
‘Hotchip’ Board is based on Atmel’s 
AVR 8535 RISC technology and 
will interest both the beginner and 
expert alike. Beginners will find that 
they can write and test a simple 
program, using the BASIC 
programming language, within an 
hour or two of connecting it up. 
Experts will like the power and flexibility of the ATMEL microcontroller, 
as well as the ease with which the little Hot Chip board can be 
“designed-in” to a project. The ABC Mini Board ‘Starter Pack’ includes 

just about everything you need to get up and experimenting right 

away. On the hardware side, there’s a pre-assembled micro controller 
PC board with both parallel and serial cables for connection to your 
PC. Windows software included on CD-ROM features an Assembler, 
BASIC compiler and in-system programmer The piaeene 
boards only are also available separately.. 


Advanced 32-bit Schematic Capture 
and Simulation Visual Design Studio 

ABC MINI Starter Pack 

ABC MINI Board Only | £39.95 

; Spice and POD Notiea Garmention, Cre 
7 Model | Wizard allows you te download and import models 
i from device manulacturers web page. 

Ativanced 32-bit Analogue, Digite!, & Mixed Mode Sinnulation 
Virtual Instruments: Ohen/Volts rrentPower Mulbmeter 
shows complex Voltage, Current, Phase, Magnitude ete. 

Built in Hosmer aie Real-Time Virtual Oscilloscope 

Buit in ‘ai Logic Analyzer allows you to set breakpoints 
Supports dvanced BSIM3v3, BSIMA, and SOI Models 

21 Different analysis types including advanced Monte CarloANC 

 VisualSpice Software Options 
| Personal Edition £74.95 Standard Edition £124.95 

: Professional Edition £174.95 
i See web site for full details and dem 

Serial Port Isolated I/O — 

Kit provides eight relay outputs 
capable of switching 4 amps at mains 
voltages and four optically isolated 
digital inputs. Can be used in a variety 
of control and sensing applications 
including load switching, external 
switch input sensing, contact closure 
and external voltage sensing.” “ 

Programmed via a computer serial port, it is compatible with ANY 
computer & operating system. After programming, PC can be 
disconnected. Serial cable can be up to 35m long, allowing 

‘remote’ control. User can easily write batch file programs to 

control the kit using simple text commands. NO special software 
required — uses any terminal emulator program (built into 
Windows). All components provided including a plastic case with 
pre-punched and silk screened front/rear panels to give a 
professional and attractive finish (see photo). 

Serial Port Isolated 1/O Controller Kit 

AS3108 Assembled Serial Port Isolated I/O Controller | £64.95 


= }- Oo ae «eee 2 Se 


you can start straight away! 

ee es ee ee ee ee 
en as == ay 
Z : ie 

Signal Diodes 1N4148 

Rectifier Diodes 1N4001 

Rectifier Diodes 1N4007 

W01 Bridge Rectifiers 

555 Timer |.C.s ...... 20.0... cece eee eee £1.00 
741 Op Amps 

heoored Zener Diodes 400mW 
Assorted 7-segment Displays 

5mm l.e.d.s, red, green or yellow 
3mm |.e.d.s, red, green or yellow 
5mm |.e.d.s, green, 65mm legs 

Axial |.e.d.s, 2mcd red Diode Package 
Asstd. High Brightness |.e.d.s, var cols 
BC182L Transistors 

BC212L Transistors 

BC237 Transistors 

BC327 Transistors 

BC328 Transistors 

BC547 Transistors 

BC547B Transistor 

BC548 Transistors 

BC549 Transistors 

BC557 Transistors 

BC558 Transistors 

BC559 Transistors 

2N3904 Transistors 

inf 50V wkg Axial Capacitors 

4N7 50V wkg Axial Capacitors 

Asstd capacitors electrolytic- 

Asstd. Radial Electrolytics, 4-7-2200uF 


4-ch 150MHz delay,, 
cursors etc, Supplied 

with 2 Tektronix probes. 

TEKTRONIX 2232 Digital Storage Scope. 
Dual Trace, 100MHz, 100M/S with probes .. . 
H.P. 54501A Dig. Oscilloscope, 100MHz 4-Ch .. 
H.P. 3312A Function Gen., 0-1Hz-13MHz, 
AM/FM Sweep/Tri/Gate/Brst etc. 30 
FARNELL Dual PSU XA35-2T, 0-35V, 0-2A, 

Twice QMD, I.c.d. Display £18 
CIRRUS CRL254 Sound Level Meter 

with Calibrator 80-120dB, LEQ 

FARNELL AMM255 Automatic Mo 

Meter, 1-5MHz-2GHz, unused 

FARNELL DSG1 Low Frequency Syn Sig. Gen., 
0-001Hz-99-99kHz, low distortion, 
TTL/Square/Pulse Outputs etc. £95 
FLUKE 8060A Handheld True RMS, DMM, 

4% digit As new £150, used £95 
BECKMAN HD110 Handheld 3% digit DMM, 28 
ranges, with battery, leads and carrying case .£40 
H.P. 3310A Function Gen., 0-005Hz-5MHz, 
Sine/Sq/Tri/Ramp/Pulse £125 
FARNELL LFM4 Sine/Sq Oscillator, 10Hz-1MHz, 
low distortion, TTL output, Amplitude Meter .£125 
H.P. 545A Logic Probe with 546A Logic 

Pulser and 547A Current Tracer 

FLUKE 77 Multimeter, 3¥2-digit, handheld .. . 
FLUKE 77 Series 11 

HEME 1000 L.C.D. Clamp Meter, 00-1000A, 

in carrying case 



Generator from £75-£125 
THURLBY/THANDER TG210 Function Generator, 
0-002Hz-2MHz, TTL etc £80-£95 
0A-2A Twice (late colours £2 

Datron 1061 
High Quality 5-5 Digit Bench 

True RMS/4 wire Res/Current Converter/IEEE 

Datron 1061A 
High Quality 6% digit Bench 

Multimeter & 
True RMS/4 wire/Current Converter 

Racal Receiver RA1772 
L.E.D. Display. Basically working. 

whenever and wherever you like, at a pace that suits you best to 
gain the qualification you want. You'll even have the back-up of | |) C&G Basic Electronic 
student services, and access to a personal tutor, and best of all, 

=y Vite), 74 oe 

Asstd. capacitors 1nF to 1uF 

Asstd. disc ceramic capacitors 

Asstd. Skel Presets (sm, stand, cermet) 

Asstd. RF chokes (inductors) 

Asstd. grommets 

Asstd. solder tags, p/conns, terminals 

Asstd. crystals - plug in 

Asstd. dil switches 

Miniature slide switches sp/co 

Asstd. push-button switches, multi-bank, multi-pole . 
Asstd. dil sockets up to 40 way 

TV coax plugs, plastic 

metres very thin connecting wire, red 

lin. glass reed switches 

Asstd. IFTs (no data) 

Any one value %4W 5% cf resistors range 1R to 10M £0.45 
7812 Voltage Regulators | 
Asstd. resistors, W/YeW, mostly on tapes 


288 Abbeydale Road, Sheffield S7 1FL 

Phone: 0114 255 2886 y& Fax: 0114 255 5039 
e-mail: sales @ * Web: 

Prices include VAT.Postage £1.65 
44p stamp for lists or disk 

POs, Cheques and Credit Cards accepted 


80 kHz - 1040MHz 


MARCONI 893C AF Power Meter, Sinad Measurement 

MARCONI 893B, No Sinad 

MARCONI 2610 True RMS Voltmeter, Autoranging, 
5Hz-25MHz £19 
GOULD J3B Sine/Sq Osc., 10Hz-100kHz, 

low distortion 

AVO 8 Mk. 6 in Every Ready case, with leads etc. . .£80 

‘Other AVOs from 

GOODWILL GVT427 Dual Ch AC Millivoltmeter, 
10mV-300V in 12 ranges, Freq. 10Hz-1MHz . .£100-£125 
SOLARTRON 7150 DMM 6%-digit 


SOLARTRON 7150 Plus 

9904 Universal Timer Counter, 50MHz 
9916 Counter, 10Hz-520MHz 
9918 Counter, 10Hz-560MHz, 9-digit 
WAYNE KERR B424 Component Bridge ... . 
RACAL/AIM 9343M LCR Databridge. 
Digital Automeasurement of R,C,L,Q,D ... 
FLUKE 8050A 4-5 Digit. 2A. True RMS 
FLUKE 8010A 3-5 Digit. 10A 
FLUKE 8012A 3-5 Digit. 2A 

Racal 9008 

Automatic Modulation Meter, 
AM/FM 1-5MHz-2GHz 

Portable Appliance Tester GED 
Megger Pat 2 

H.P. 6012B DC PSU 0-60V, 0-50A, 1000W_ .£1000 
FARNELL AP60/50 1KW Autoranging 

FARNELL H60/50 0-60V 0-50A 

FARNELL H60/25 0-60V, 0-25A 

Power Supply HPS3010, 0-30V, 0-10A 

FARNELL L30-2 0-30V, 0-2A 

FARNELL L30-1 0-30V, 0-1A 

Many other Power Supplies available 


‘) Telephone: (0118) 9268041. Fax: (0118) 9351696 A 
Callers welcome 9am-5.30pm Monday to Friday (other times by arrangement) 


| C&G Basic Mecha 

Tel, No. 

Engineering Email 

LTD (Est. 

Dual Trace, 20OMHz 
Tested with Manual 


TEKTRONIX TDS350 dual trace, 200MHz, 1G/S . Unused £1500 

TEKTRONIX TDS320 dual trace, 100MHz, 500M/S 

TEKTRONIX TDS310 dual trace, 50MHz, 200M/S 

LECROY 9400A dual trace, 175MHz, 5G/S 

HITACHI VC6523, d/trace, 20MHz, 20M/S, delay etc. Unused £600 
PHILIPS PM3092 2+2-ch., 200MHz, delay etc., £800 as new £950 
PHILIPS PM3082 2+2-ch., 100MHz, delay etc., £700 as new £800 
TEKTRONIX TAS465 dual trace, 100MHz, delay etc. ...... £750 
TEKTRONIX 2465B 4-ch., 400MHz, delay cursors etc .. . £1500 
TEKTRONIX 2465 4-ch., 300MHz, delay cursors etc. ..... £900 
TEKTRONIX 2445/A/B 4-ch 150MHz, delay cursors etc .£500-£900 
TEKTRONIX 468 Dig. Storage, dual trace, 100MHz, delay . . .£450 
TEKTRONIX 466 Analogue Storage, dual trace, 100MHz ... . 
TEKTRONIX 485 dual trace, 350MHz, delay sweep 

TEKTRONIX 475 dual trace, 200MHz, delay sweep 

TEKTRONIX 465B dual trace, 100MHz, delay sweep 

PHILIPS PM3217 dual trace, 50MHz delay 

GOULD 0S1100 dual trace, 30MHz delay 

HAMEG HM303 dual trace, 30MHz component tester 

HAMEG HM203,7 dual trace, 20MHz component tester ... . 
FARNELL DTV20 dual trace, 20MHz component tester .. . £125 
Many other Oscilloscopes available 

MARCONI 2022E Synth AM/FM Sig Gen 
10kHz-1-01GHZz l.c.d. display etc 

H.P. 8657A Synth sig gen, 100kHz-1040MHz 

H.P. 8656B Synth sig gen, 100kHz-990MHz 

H.P. 8656A Synth sig gen, 100kHz-990MHz 

R&S APN62 Synth, 1Hz-260kHz sig. gen., 

balanced/unbalanced output, |.c.d. display 

PHILIPS PM5328 sig gen, 100kHz-180MHz with 
200Mk7z, freq. counter, IEEE 

RACAL 9081 Synth AM/FM sig g en, 5kHz-1024MHz 

H.P. 3325A Synth function gen, 21MHz 

MARCONI 6500 Amplitude Analyser 

H.P. 4192A Impedance Analyser . . . .- 

H.P. 4275A LCR Meter, 10kHz-10MHz 

H.P. 8903A Distortion Analyser 

WAYNE KERR 3245 Inductance Analyser 

H.P. 8112A Pulse Generator, 50MHz 

MARCONI 2440 Frequency Counter, 20GHz 

H.P. 5350B Frequency Counter, 20GHz 

H.P. 5342A 10Hz-18GHz Frequency Counter 

H.P. 1650B Logic Analyser, 80-channel 

MARCONI 2035 Mod Meter, 500kHz-2GHz 

MARCONI 2955/2995A 

Date of Birth sual 



Built-in transistor test socket 
and diode test position. 
DC volts 200mV to 1000V. 
AC volts 200V to 750V. 
DC current 200mA to 10A. 
Resistance 200 ohms to 
2000K ohms. 

£5.99 incl. VAT 


H.P. 6063B DC Electronic Load, 3-240V/0-10A, 250W 

H.P. 66312A PSU, 0-20V/0-2A 

H.P. 66311B PSU, 0-15V/0-3A 

H.P. 66309D PSU Dual, 0-15, 0-3A/0-12, 0-1-5A 

H.P. 6632B PSU, 0-20V/0-5A 

H.P. 6623A PSU, triple output ranging from 0-7V 0-5A to 
0-20V 0-4A 

H.PJAGILENT 34401A DMM 6% digit 

H.P. 3478A DMM 5% digit 

FLUKE 45 DMM dual display 

KEITHLEY 2010 DMM 7% digit 

KEITHLEY 617 Programmable Electrometer 

H.P. 4338B Milliohmmeter 

RACAL Counter type 1999 2.6GHz 

H.P. Counter type 53131A 3GHz 

H.P/AGILENT 33120A Func. Gen/ARB, 100wHz-15MH 

SONY/TEKTRONIX AFG320 Arbitary Func. Gen 

H.P. 8904A Syn. Function Gen, DC-600kHz £1000/£1250 

BLACK STAR JUPITOR 2010 Func. Gen, 0-2Hz-2MHz with 
frequency counter 

H.P. 8116A Pulse Generator, 1mH-50MHz 

H.P. 8657B Syn Sig. Gen, 0-1-2080MHz 




H.P. 8561B 50Hz-6-5GHz 

H.P. 8560A 50Hz-2-9GHz synthesised 

H.P. 8594E 9kHz-2-9GHz 

H.P. 8591E 1MHz-1-8GHz, 75 Ohm 

H.P. 853A with 8559A 100kHz-21GHz 

H.P. 8558B with Main Frame, 100kHz-1500MHz 
H.P. 3585A 20Hz-40MHz 

H.P. 3580A 5Hz-50kHz 

ADVANTEST R4131B 10kHz-3-5GHz 
EATON/AILTECH 757 0-001-22GHz 

MARCONI 2382 100Hz-400MHz, high resolution 
MARCONI 2370 30Hz-110MHz 

H.P. 182 with 8557 10kHz-350MHz 


8553 1kHz-110MHz 

8554 500kHz-1250MHz 

8555 10MHz-18GHz 

TEKTRONIX 491 10MHz-12-4GHz 

H.P. 8443 Tracking Gen/Counter, 110MHz 

H.P. 8444 OPT 059 

B&K 2033R Signal Analyser 

H.P. 5372A Frequency & Time Interval Analyser 
H.P. 8754A Network Analyser, 4MHz-1300MHz 
H.P. 3557A Network Analyser, 5Hz-200MHz 
H.P. 53310A Mod Domain Analyser Opt 001/003 
ONO SOKKI CF300 Portable FFT Analyser 

Used Equipment — GUARANTEED. Manuals supplied 
This is a VERY SMALL SAMPLE OF STOCK. SAE or Telephone for lists. 
Please check availability before ordering. 

CARRIAGE all units £16. VAT to be added to Total of Goods and Carriage 

Everyday Practical Electronics, September 2002 

UANYAYTAY ie) aale mere U1 4 

elim Pl-\elitcminelim-lacomelaliiat-melcc(-1alale Mem alae 

~ Simulate, Trace at up to 10x the speed of MPLAB 

Development Board PIC 
@ —_ Handles 40 pin PIC devices including Programmer 
18F452 and 16F877 including 
® — on board Biscleides —no 18Cxxx and 
separate programmer require 

Price — £45.00 Built and Tested. 16F877-20P 
£6.00, 18F452 £8.00, CD with BASIC & 
Programmer Applications £5.00 

18F452 now supported in our C Compiler, WIZ-C, WIZ-ASM Development board and programmer 
WIZ-C Compiler including support for 18F452 and 16F877 

Boathon ean 

What is the WIZ-C Rapid Application Environment? 

Our PIC C compiler including a new front end . 
An application designer for the FED PIC C Compiler — 6S 
Drag a software component onto your design & set up the 
parameters using check boxes, drop down boxes and edit boxes 
(see shot right) | 

Connect the component to the PIC pins using the mouse 

Select your own C function to be triggered when events occur 
(e.g. Byte received, timer overflow etc.) 

Generate the base application automatically and then add your 
own functional code in C or assembler ROOD 
Supports 14/16 bit core PICS 

16F87x, 16C55x, 16C6x, 16F8x, 16C7xx, 18Cxx, 18Fxx etc. 
C Compiler designed to ANSI C Standards 

Prices | 
WIZ — C Standard — £70.00, 
Professional £100.00. Upgrade for 
existing WIZ-C owners £30.00 
PIC C Compiler Standard — £60.00, 
Professional £90.00. Upgrade for 
existing Compiler owners £30.00 
Other upgrade options are 
available together with reduced 
price bundled packages — see 
our web site for details 

Professional Version Enhancements 
to our C Compiler and WIZ-C Rapid Application Environment 

Manage and simulate multiple projects together 

Connect PIC pins across projects to allow simulated devices to communicate 
Handle assembler and C projects 

View and inspect variables in native C format 

Inspect all local variables and their values in native C format 

Maintain a history within simulation to back track and determine the past leading 
up to an event 

Other products supporting 18F452 and 16F877 

4 LED’s on board, Analogue on trimpot, 

2 duplex serial ports 

1A 5V regulator 

20MHz crystal 

Interfaces for LCD, hex keypad, 32 I/O pins 
on IDC connectors 

Will run FED PIC BASIC (included on CD) 
12C EEPROM socket 

Handles serially 
programmed PIC 
devices in a 40 pin 
multi-width ZIF 
socket. 16C55X, 
16C6X, 116F62x, 
6C7X, 16C8x, 
16F8X, 12C50x, 
12C67x, 16C72X, 
PIC14000, 16F87X, 
18Cxxx, 18F xxx etc 

Also In-Circuit programming. Operates 
on PC serial port. 
Price: £45/Kit 

£50/Built & Tested 

In Circuit Debugger 

In Circuit Debugging is a technique where a 
monitor program runs on the PIC in the appli- 
cation circuit. The ICD board connects to the 
PIC and to the PC. From any of our applica- 
tions it is then possible to set breakpoints on 
the PIC, run code, single step, examine regis- 
ters on the real device and change their val- 

ues. The ICD makes debugging real time 
applications faster, easier and more accurate 
than simulation tools available for the PIC. 
@ Only £30.00, requires a copy of WIZASM, 
WIZ-C or our C Compiler applications. 
Operates with 16F87x to emulate most 
14 bit core chips, 18F support coming 
soon ! 

PIC Chips 
PIC 16F877-20P, £6.00, 20MHz, 384 bytes RAM, 8K Wrd ROM 
PIC 18F452, 40MHz, £8.00 1500 bytes RAM, 16K Wrd ROM, 
New 18 series architecture with flat memory address space, 3 
timers, 2 Capture compare registers, various serial interfaces, 
Parallel peripheral interface, 32 general purpose 1/O pins, Flash 
reprogrammable in circuit. Supported by all our tools and the 
free Microchip development system - MPLAB 

Other products 
FED also supply development systems for PIC and AVR in 
assembler and C. Please see our web site for further details. 

Forest Electronic Developments 01590-681511 (Voice/Fax) | nn  EUROCARD. 
12 Buldowne Walk, Sway,LYMINGTON, HAMPSHIRE, S041 6DU. = 
Email - info, or sales @ AA ee 
Web Site - 

Prices - UK/Europe, please add VAT at 17.5%. Add £3.00 for P&P and handling to each 
order. Cheques/POs payable to Forest Electronic Developments, phone with credit card or 
Switch details, or use our secure web site for online ordering with credit card. 


Tel 01283 565435 Fax 546932 
E-mail: sales @ 



135 Hunter Street, Burton-on-Trent, Staffs. DE14 2ST 

All Prices include V.A.T. ADD £3.00 PER ORDER P&P. £6.99 next day 



The latest MAGENTA DESIGN - highly 
stable & sensitive — with |.C. control of all 
timing functions and advanced pulse 
separation techniques. 

@ High stability 

drift cancelling 
@ Easy to build 

& use 
@ No ground 

effect, works 

in seawater 



An affordable circuit which-sweeps 
the incoming water supply with 
variable frequency electromagnetic 
signals. May reduce scale formation, 
dissolve existing scale and improve 
lathering ability by altering the way 
salts in the water behave. 

Kit includes case, P.C.B., coupling 
coil and all components. 

High coil current ensures maximum 

effect. L.E.D. monitor. 
POWER UNIT....:.£3.99 

KIT 868 ....... £22.95 


Our latest design — The ultimate 
scarer for the garden. Uses 

special microchip to give random 
delay and pulse time. Easy to 

build reliable circuit. Keeps pets/ 
pests away from newly sown areas, 
play areas, etc. uses power source 
from 9 to 24 volts. 


e Detects gold, 
silver, ferrous & 

e Efficient quartz controlled 

microcontroller pulse generation. 
@ Full kit with headphones & all 

KIT 847 . » £63.95 

PEsT SCARER @ DUAL OPTION Plug-in power supply £4.99 
A powerful 23kHz ultrasound generator in a 
compact hand-held case. MOSFET output drives KIT 867. ses ees ee eee seeeeeeeee an a 9.99 
a special sealed transducer with intense pulses 
via & Special tuned tranetormer, Sweeping Nt AVE UNI ie en cca sn dees ates 2.00 
frequency output is designed to give maximum 
output without any special setting up. WI N DICATOR 
KIT 842 £22.56 A novel wind speed indicator with LED readout. Kit comes 

_— — = . complete with sensor cups, and weatherproof sensing head. 

Mains power unit £5.99 extra. 
DEVELOPMENT | KIT 856................ 000 e nee uceees £28.00 



@ 8MHz 68000 16-BIT BUS 






As featured in March ‘97 issue. 

Magenta have prepared a FULL KIT for this. 
excellent new project. All components, PCB, 
hardware and electrodes are included. 
Designed for simple assembly and testing and 
providing high level dual output drive. 

KIT 866. . Full kit including four electrodes £32.90 

1000V & 500V INSULATION 

Superb new design. Regulated 
output, efficient circuit. Dual-scale 
meter, compact case. Reads up to 
200 Megohms. 

Kit includes wound coil, cut-out 
Pcase, meter scale, PCB & ALL 

KIT 848............ £32.95 

4 spare 


KIT 621 



e PSU £6.99 

e SERIAL LEAD £3.99 

Stepping Motors 

MD38...Mini 48 step...£8.65 
MD35...Std 48 step...£9.99 
MD200...200 step...£12.99 

MD24...Large 200 step...£22.95 


Full set of to quality NEW 
components for this educa- 
tional series. All parts as 
specified by EPE. Kit includes 
breadboard, wire, croc clips, 
pins and all components for 
experiments, listed in 

introduction to Part 1. 
“Batteries and tools not included. 

| TEACH-IN 2000 - 

KIT 879 £44.95 


An innovative and exciting project. 

Wave the wand through the air and oy 
your message appears. Programmable Fm 
to hold any message up to 16 digits long. WS, 
Comes pre-loaded with “MERRY XMAS”. Kit oss w . 

includes PCB, all components & tube plus ®, bs 



instructions for message loading. 

KIT 849 


A safe low cost eraser for up to 4 EPROMS ata 

time in less than 20 minutes. Operates from a 
12V supply (400mA). Used extensively for mobile 
work - updating equipment in the field etc. Also in 
educational situations where mains supplies are 
not allowed. eer interlock prevents contact 
with UV. 

RUE 190 os cme etiiadnes £29.90 



A new circuit using a 
‘full-bridge’ audio 
amplifier i.c., internal 
speaker, and 
headphoneftape socket. 
The latest sensitive 
transducer, and ‘double 
balanced mixer give a 
stable, high perfor- 
mance superheterodyne design. 

KIT 861...........£24.99 

ALSO AVAILABLE Built & Tested. . . £39.99 


Based on our Mk1 design and 
preserving all the features, but 
now with = switchin pre- 
regulator for much higher effi- 
ciency. Panel meters indicate 
Volts and Amps. Full | variable 
down to zero. Toroidal mains 
transformer. Kit includes 
punched and printed case and 
all parts. As featured in April 
1994 EPE. An essential piece 
of equipment. 


Programmed PICs for 
all* EPE Projects 
All £5.90 each 
PIC16F877 now in stock 
£10 inc. VAT & postage 
(“some projects are copyright) 

Kit No. 845......... £64.95 


KIT 812...... 


Keep pets/pests away from newly 
sown areas, fruit, vegetable and 
flower beds, children’s play areas, 
patios etc. This project produces 
intense pulses of ultrasound which 
deter visiting animals. 





Everyday Practical Electronics, September 2002 


Power Supply £3.99 

PIC 16F84 £4.84 



Based on February ’96 EPE. Magenta designed PCB and kit. PCB 
with ‘Reset’ switch, Program switch, 5V regulator and test L.E.D.s, 
and connection points for access to all A and B port pins. 

Kit 860 £19.99 

Power Supply £3.99 


Another super PIC project from Magenta. Supplied with PCB, industry standard 2-LINE x 
16-character display, data, all components, and software to include in your own programs. 
Ideal development base for meters, terminals, calculators, counters, timers — Just waiting 
for your application! 











it 855 £39.95 

As featured in Aug./Sept. 99 EPE. Full kit with Magenta 
redesigned PCB — LCD fits directly on board. Use as Data 

mel or as a test bed for many other 16F877 projects. Kit 
includes programmed chip, 8 EEPROMs, PCB, case and all components. 

KIT 877 £49.95 inc. 8 x 256K EEPROMS 




Now features full 4-channel chaser 
software on DISK and pre- 
programmed PIC16F84 chip. Easily 
re-programmed for your own applica- 
tions. Software source code is fully 
‘commented’ so that it can be 
followed easily. 


PIC Real Time 
In-Circuit Emulator 

@ Icebreaker uses PIC16F877 in circuit debugger 

@ Links to Standard PC Serial Port (lead supplied) 

@ Windows™ (95+) Software included 

@ Works with MPASM and MPLAB Microchip software 

@ 16x 2L.C.D., Breadboard, Relay, I/O devices and patch leads supplied 

As featured in March ’00 EPE. |deal for beginners AND advanced users. 

Programs can be written, assembled, downloaded into the microcontroller and run at full 
speed (up to 20MHz), or one step at a time. 

Full emulation means that all I/O ports respond exactly and immediately, reading and 
driving external hardware. 

Features include: Reset; Halt on external pulse; Set Breakpoint; Examine and Change 
registers, EEPROM and program memory; Load program, Single Step with display of 
Status, W register, Program counter, and user selected ‘Watch Window’ registers. 

KIT 900... £34.99 


Fax: 01283 546932 

Tel: 01283 565435 
Everyday Practical Electronics, September 2002 



= ad = od | Onn O10) Ck 



KIT 880 . . . £34.99 with 16F84 . . . £39.99 with 16F877 








KIT 878 .. . £22.99 with 16F84... £29.99 with 16F877 

EPE PIC Tutorial 

At last! A Real, Practical, Hands-On Series 

e Learn Programming from scratch using PIC16F84 

e Start by lighting l.e.d.s and do 30 tutorials to 
Sound Generation, Data Display, and a Securit 

e PIC TUTOR Board with Switches, l.e.d.s, and on 
board programmer 

Includes: PIC16F84 Chip, TOP Quality PCB printed with 
Component Layout and all components* (*not ZIF Socket or 
Displays). Included with the Magenta Kit is a disk with Test 
and Demonstration routines. 

KIT 870 .... £27.95, Built & Tested .... £42.95 
Optional: Power Supply — £3.99, ZIF Socket — £9.99 
LCD Display ........... £7.99 LED Display ............ £6.99 
Reprints Mar/Apr/May 98 — £3.00 set 3 



e PIC16C6X, 7X, AND 8X 

Power Supply £3.99 



Kit 863 £18.99 




Another NEW Magenta PIC project. Drives any 4-phase unipolar motor — up 
to 24V and 1A. Kit includes all components and 48 step motor. Chip is 
pre-programmed with demo software, then write your own, and re-program 
the same chip! Circuit accepts inputs from switches etc and drives motor in 
response. Also runs standard demo sequence from memory. | 

All prices include VAT. Add £3.00 p&p. Next day £6.99 

E-mail: sales @ 


RF Connectors Boxes & Cases 3.579545MHz £0.41 
ie e Many more sizes available 3.6864MHz £0.41 
jo : OMHz £0.4] 
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jam 4.433619MHz £0.41 
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DC Chassis Skt 2. Zorn £0.41 3A 110VSPDT12V £0.60 g " 
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IDC Cable Sock _» 13 Way Female Socket£1.32 5A 110V DPDT12V_ £0.93 inne £1.03 Infre Devices 
a 25 Way Male Plug £1.10 5A 240V DPDT6V. = £1.76 20 SWG Tinned £1.06 3mm IR Emitter £0.15 
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one Te . inne mm Photo-Transistor 
Right Angled PCB g Pin IEC Line Socket £1.08 10A 240V SPDT EY, £1.20 26 SWG Tinned © £1.08 5mm Photo. Transistor £0. 92 
10 Way Socke £0.23 3 Pin Chassis Socket £0.55 10A ane SPDT 24V £1.44 Be ren, Re Red. Citaane (ree Bier cou ™ anne 58 
1 Way Socket £0.37 & Way Bulgin <”” Yellow, Green, Blue Purple, 4N26 Opto- Coupler £0. 36 
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ay Socke 
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IDC Cable Plugs 13 Way H.D. Socket £0.58 § Pin Chassis Skt Po Po5p £1.08 an Gender Changer + £1.73 Sm 85/04 Cable £2.16 CNY17-1'Q-Coupler £0.3 
weypeg SE Ney leh Pomp Fons Reeth Regen we 0 Boe SI BSE Be 
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Switches 25F Gender Changer £2.43 ‘ 
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40 Way Plug £0.92 23 Way Cover - Grey £0.38 Sub-Miniature 2F- 6 Mini Din Female£2. = 32,7 68K £0.39 MOE3041 Opto-Triac£0.70 
50 Way Plug £1.12 23 Wav Cover - Bla “£9.38 3A 125V 1A 250V 5M Din 6E Mint Din £1.73 N€-49/U Case Miai LDR 60:45 
a5 Way Caver< €0:34 5mm @ Mounting Hole af Din - yy A Mini Din £1.73 1.8432MHZ £1.08 Orp12 LDR £110 
PCB Box $2 Way Gover - Grey foc, SPST 5x lomm £0.53 Teste Z.0MHZ £1.46 | 
Headers 9t09Cover/Case £0.80 SPDT 5x 10mm £0.53 Mini Tester 7 LEDs C4. 72 : z : 
25 to 25 Cover / Case £0.84 SPDT C/O 5 x 10mm £1.01 Check Tester 18 LEDs £6.32 3.2768MHz £0.51 
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10 Woy Straight £0.22 Audie Connectors 6A 125V 3A 250V Anii-Static Wrst Strap£4.76 Technical Books & 
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16 Way Straight : x lomm fe rofector Data Table & Equivalent charts from eB 
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26 Way Straight 5 beams pes Sac et £016 ent iva x or at & fk: 9 ‘Cab plock £10.50 Hlents & selector tables for semiconduc- = , 
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ct ie 4" Stereo Plug £0.40 SPOT c/off 18x 30mm £1.18 2m IEEE] 284 Printer L £4.38 [oplitinto Wwo paper volumes or available on one : 
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21 00. 
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34 Way Straight £0.88 Red Line Socket £0.20 DPDT 7 x 23mm £0.17 25Mgle to 25Female £3.78 
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Email: enquiries @ 

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See notes on Readers’ Technical Enquiries below — we regret 

The Now| MAGAZINE FOR ELECTRONICS TECHNOLOGY & COMPUTER PROJECTS s technical enquiries cannot be answered over the tele- 

Advertisement Offices: 

VOL. 31 No.9 SEPTEMBER 2002 


Phone/Fax: (01255) 861161 


Next month we delve into the mysteries of the past. A hobby that has become 
established over the last decade is that of collecting old radios, communications 
equipment, test gear etc. There is now a well-established vintage radio trade in the 
UK and around the world, an interest catered for by our sister publication Radio 
Bygones, which is the leading British publication for vintage radio enthusiasts. 

In a special 16-page supplement Free with next month’s EPE we will take a look 
at what is available, what and how to buy, restoration and suppliers. It is fascinating 
to restore equipment from 50 years ago and then use it. Of course, all the old radios 
can still be used and most of the test equipment likewise. The technology is rather 
different from that of today so, for many readers, it will mean learning about valves, 
but, of course, these are still used by most of us everyday in the rather specialised 
form of the cathode ray tube, which was actually invented in 1859! 

Whilst the technology is certainly very different, most of the parts are still readily 
available and many of them have changed very little over the last 50-odd years. What 
has changed is the style of cases etc., but a couple of manufacturers are now recreat- 
ing radios in the style of 60s sets, namely Bush and Roberts Radio. So there must be 
something to be said for the designs of yesteryear. | 

EPE has published the occasional valve project, and a number of guitarists and 
hi-fi enthusiasts still believe the valve sound is the best. Certainly collecting and 
restoring valve hi-fi equipment is also booming in the UK. 


For anyone interested in old radios, communications equipment, record players, 
juke boxes, telephones, hi-fi etc., then a visit to the NEC on September 15th will be 
worthwhile. The National Vintage Communications Fair is held on that day and 
hundreds of companies take stands to sell everything from valves and components 
through vintage radios, TVs, telephones and hi-fi up to juke boxes and even tele- 
phone boxes. It is well worth a visit and Radio Bygones will be there selling back 
issues, books, data CD-ROMS etc. 

If you are interested in this facet of electronics, then why not go along and see 
what it is all about. 


Copies of EPE are available on subscription anywhere 

in the world (see below), from all UK newsagents - 

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Everyday Practical Electronics, September 2002 


Technical Editor: JOHN BECKER 
Business Manager: DAVID J. LEAVER 
Subscriptions: MARILYN GOLDBERG 
Administration: FAY KENWARD 
Editorial/Admin: (01202) 873872 

Advertisement Manager: 
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EPE Online (internet version) Editors: 


E-mail: techdept @ 
We are unable to offer any advice on the use, 
purchase, repair or modification of commercial 
equipment or the incorporation or modification 
of designs published in the magazine. We 
regret that we cannot provide data or answer 
queries on articles or projects that are more 
than five years old. Letters requiring a personal 
reply must be accompanied by a stamped 
self-addressed envelope or a_ self- 
addressed envelope and international reply 
coupons. All reasonable precautions are 
taken to ensure that the advice and data given 
to readers is reliable. We cannot, however, 
guarantee it and we cannot accept legal 
responsibility for it. 


We do not supply electronic components or 
kits for building the projects featured, these 
can be supplied by advertisers (see Shoptalk). 
We advise readers to check that all parts 
are still available before commencing any 
project in a back-dated issue. 


Although the proprietors and_ staff of 
reasonable precautions to protect the interests 
of readers by ensuring as far as practicable 
that advertisements are bona fide, the maga- 
zine and its Publishers cannot give any under- 

takings in respect of statements or claims 

made by advertisers, whether these advertise- 
ments are printed as part of the magazine, or 
in inserts. 

The Publishers regret that under no circum- 
stances will the magazine accept liability for 
non-receipt of goods ordered, or for late 
delivery, or for faults in manufacture. 


We advise readers that certain items of radio 
transmitting and telephone equipment which 
may be advertised in our pages cannot be 
legally used in the UK. Readers should check 
the law before buying any transmitting or 
telephone equipment as a fine, confiscation of 
equipment and/or imprisonment can result 
from illegal use or ownership. The laws vary 
from country to country; readers should check 
local laws. 


Constructional Project == 


An automatic flight attitude control system 
suitable for free flight model gliders 

summer, the author made a number of 

model gliders, which were taken to the 
top of a local hill and then launched. The 
models were made from balsa wood and 
were not powered in any way, except by 

Several designs showed some promise, 
but maintaining level flight with any con- 
sistency was a problem. Promising designs 
were shelved because after 20 metres they 
showed signs of losing stability, preferring 
to roll over or stall with the occasional 
“crump” of deforming balsa wood. 


As their glides were observed, it seemed 
apparent that it must be possible to incor- 
porate an automated flight control system, 
to give the designs at least a fighting 
chance. Following a number of prototypes, 
this article describes how to make and 
install into a model glider a low cost 
microcontrolled stabilisation system that 

‘ N order to amuse his young nephew last 


helps model gliders to fly a little more 
straight and level. 

Glider flight times have been increased 
from an average of five to six seconds to over 
15 seconds — the limitation now being that 
the author’s local hill is just not big enough! 
The real power of Freebird is that the flight 
correction algorithm can be modified by re- 
programming the PIC16F84A microcon- 
troller, which handles the attitude detection 
and flight correction, all in real time. 


To encourage budding aeronautical 
engineers (young and old) to take up this 
mid-summer madness, an overview of air- 
craft flight dynamics and some practical 
flying information has also been included. 
The design has been kept simple, using 
low cost and readily available components. 
For inexperienced model makers, a glider 
can be purchased. 

During development, a portable com- 
puter was used in conjunction with the 

EPE Toolkit Mk3 (Oct/Nov ’01), to provide 
full “in-the-field” tuning of the software, 
but this is not essential. 


A full analysis of how aircraft fly is a 
complicated subject and cannot be fully 
detailed here. Further reading on the sub- 
ject of aerodynamics is given at the end of 
this article. 

In summary, for a fixed wing aircraft to 
fly, it must be made to move forward. The 
wings are designed to convert part of the 
falling motion into a forward motion. As 
the wings move forward they produce lift, 
which acts against the weight of the glider, 
effectively making it “lighter”. The 
“lighter” glider in turn requires less for- 
ward speed so it settles into stable forward 

The forces acting on a glider in stable 
flight are shown in Fig.1. The main forces 

@ Lift force generated by the wings 

@ Weight of the glider and control elec- 
tronics (downwards) 

@ Drag or retardation force as the glider 
tries to move through the air (back- 

@ Propulsive force which for gliders is 
supplied by gravity (forwards). 

In stable flight, the lift force is just less 
than the weight force, (i.e. the model slow- 
ly descends) and the thrust force is greater 
than the drag force (i.e. the model moves 
slowly forward). 

The objective of glider designers is to 
maximise the distance moved forward by 
the glider and minimise the vertical dis- 
tance it falls. This is known as the optimal 
glide-slope (refer to Fig.2) and Freebird is 
aiming to keep the glider within these 
operating parameters at all times. 

Incidentally, this is also a guide to the 
slope of a good hill to launch from, as the 
glider should be able to continually “fall’’, 
yet maintain a constant height from the 

So by the addition of wings, the simple 
falling object is turned into a gliding 
object. The next problem to solve is how to 
control the motion of the aircraft in three- 
dimensional space. 

Everyday Practical Electronics, September 2002 


Aircraft travelling in space can move in 
the following ways (see Fig.3.): . 

@ Pitch — a rotation about an axis that 
passes through the wings — looks like a 
raising or lowering of the nose. To cor- 
rect alterations in pitch, the elevators 
located on the tail surfaces are adjusted 
in unison (i.e. both elevators up or both 

@ Roll — a rotation through the centre line 
of the fuselage — looks like one wing 
rises, whilst the other falls. To correct 
alterations in roll, the ailerons located 
on the wings are adjusted in opposition 
(i.e. one aileron moves up, whilst the 
other moves down). 

@ Yaw — a rotation about an axis perpen- 
dicular to the fuselage. To correct alter- 
ations in yaw, the rudder located on the 
tail is adjusted. 

When in flight, all sorts of forces act 
on the aircraft, so that at a given instant 
any combination of these motions may 
be evident — it really is a wonder that a 
hand thrown model glider flies any dis- 
tance at all! So, the idea behind Freebird 
is to correct these motions before they 
become too extreme and result in the air- 
craft crashing. 



Fig.1. Forces acting on a glider in stable flight. 

@ A computational system that detects 
attitude alterations and determines the 
correction necessary to restore normal 

@ A servo system, that can move aircraft 
control surfaces as directed by the atti- 
tude computer. 

Usually, computations are based upon 

“generic” information that forms the basis ~ 

of an in-flight mathematical model for that 
particular type of aircraft. Also, specific 
information is added that relates to that 
flight i.e. aircraft weight and ee weather 

Freebird does not carry out any mathe- 
matical computations, but outputs a pre- 
defined value of servo correction from 
look-up tables. Commercial detection 
systems make use of sophisticated detec- 
tors, including detectors sensitive to 
acceleration, which results in more 
refined control. 

Although Freebird does not offer the 
sophistication of commercial systems, it 
does incorporate all of the elements 
detailed above. 


and yaw. 

GLIDE SLOPE @ = Tan =z 6T010 

Fig.2. Optimum glide-slope. Objective is to maximise 
distance moved forward and minimise the vertical distance it 


The design for Freebird was loosely 
based upon commercial aircraft autopilot 
systems. Auto-pilots allow pilots to relax 
by flying the aircraft without any human 
intervention and are normally used in the 
mid-section of long flights where airspace 
is not crowded and there is less need for 
the aircrew to laboriously maintain a fixed 
heading and level flight. 

Any autopilot requires the following 
systems to be present: 

@ An attitude detection system. 


The complete circuit diagram for 
Freebird is shown in Fig.4. The heart of the 

system is the PIC16F84A microcontroller, | 

running at 20MHz, as set by crystal X1. 
Tilt switches sense changes in pitch (S1, 
S2) and roll (S3, S4). They are arranged in 
the same plane, but offset with each other 
at 90 degrees (see Fig.5). 

When perfectly level, the switches are 
arranged to be off, which gives a degree of 
“dead band” and helps to reduce the sensi- 
tivity of the detection system. There is no 
sensor present to detect yaw and the 

Everyday Practical Electronics, September 2002 


correction for this motion is derived from 
the measurements taken from the pitch and 
roll sensors. 

To assist the setting up procedure, light 
emitting diodes (l.e.d.s), D1 to D4, are 
included in series with the tilt switch, and 
are turned on when the respective switch 
closes. This corresponds to about 10 
degrees of tilt. 

Switches S5 to S8 are slide switches 
within a 4-way dual-in-line (d.1.1.) module. 
They allow different software routines or 
modes to be selected, as discussed present- 
ly, thereby altering the correction charac- 
teristics of Freebird. 

The software can be changed without 
the removal of the PIC from the unit, by 
means of “in-circuit” programming socket, 
SK1. Note that this does not correspond to 
the pin arrangements used by John Becker 
in his numerous EPE projects. 


Fig.3. Aircraft attitude and surfaces used to control move- 
ment. These help stabilise against me forces of pitch, roll 


The software assembly listing contains a 

full description of the PIC’s program oper- 

ation and other details, so just a short sum- 
mary is given here. The PIC undertakes the 

following tasks: 

1. Reads the mode switch and executes the 
appropriate software module 


. Detects pitch or roll tilt, by means of a 
tilt switches (active low) 


. Determines the appropriate servo(s) to 
move and by how much 

4. Determines if yaw correction is required 
based upon roll and pitch 


; sisceeh IC1 





U e 



Fig.4. Complete circuit diagram for the Freebird Glider Control. 

5. Outputs corrective commands to the roll, 
pitch and yaw servos 

The main activities are carried out in (1) 
to (4) and are arranged to loop endlessly. 
The servo output module is called by a 
timer interrupt every 18ms and this ensures 
that the servos receive their control infor- 
mation, irrespective of other activities 
going on at the time. 

The main loop senses which, if any, of 
the tilt switches are active. The combina- 
tion of tilt switch closures is used to 
enter look-up tables which define the 
appropriate degree of servo correction 
necessary. These values are placed into 
servo position register stores in readiness 
for output when the servo interrupt is 

The following modes are available in the 
software, and are selected by switches S5 
to S8: 

S5 S6 S7 

Servo Lock Servo Travel Servo Travel 
Pitch Roll 

On enabled full full 

Off disabled half half 


638 - 



Servo Lock, switch $5: When enabled, 
all servos are locked in their current posi- 
tions. This helps with alignment (say, 
checking zero, maximum up or down ele- 
vator deflection on the aircraft). It also 
allows the initial checking of l.e.d.s to be 
carried out in comparative quiet without 
the servos moving. 

Servo Travel Pitch, switch S6: the travel 
of the pitch servo can be increased or 
decreased. When enabled, the servo rota- 
tion is +60 degrees. When disabled the 
travel in each direction is halved, i.e. about 
+30 degrees. 

Servo Travel Roll, switch $7: as Pitch 
switch S6, but with respect to the roll 

Response, switch S8: when enabled 

(slow), the rate of travel of the servo move- 

ment is approximately one second from 
+60 degrees to 0 degrees. This sluggish 
response is better for flying on still, hot 

. summer days, or with 
S8 larger gliders. When 

Response disabled (fast), the 
| movement is speeded 
fast up to 0:5 seconds. 

This setting is useful 
slow in gusty conditions 
where the glider must 
respond rapidly in 
order to maintain 
Any mixture of the 
above functions can 
be selected. 


Fig.5. Attitude 
detection using tilt 
switches. Pitch 
S1/S2 and roll 
S3/S4 are 
arranged in the 
same plane, but 
offset at 90° from 
each group 



to R4 oe off) ae ©P 

RM1 1k 8-way 
s.i.1. resistor page 
All except RM1 0-25W 5% carbon film or 

Ci, C2 15p (or 10p) ceramic (2 off) 
C3 10u radial elect. 16V 
C4 220n ceramic 

Di, D4 sub-min green I.e.d. (2 off) 
D2, D3 sub-min red |.e.d. (2 off) 
D5 1N4148 signal diode 
IC1 PIC16F84A-20 
microcontroller (see text) 

Miscellaneous , 
Mito M3 Servo motor (see text) 
(3 off) 
Tilt switch (non-mercury 
type) (4 off) 
4-way d.i.l. on-off slide 
switch module 
TB1 2-way pin connector, male, 
or 1mm terminal pins 
TB2 4-way pin connector, male, 
or 1mm terminal pins 
X1 20MHz crystal 

S1 to S4 
S5 to S8 

Printed circuit board, available from 
the EPE PCB Service, code 367; battery 
pack (see text); connecting wire; solder 


Approx. Cost 
Guidance Only 
excl. servos & batts. 

Everyday Practical Electronics, September 2002 


A supply of between about 5V and 6V is 
required to power the PIC and servos. 
Power consumption peaks at around 
430mA with all three servos in motion, but 
normal steady state consumption is around 
45mA. To keep costs down, dry cells can 
be used although rechargeable cells such as 
Nickel Cadmium do help to reduce costs in 
the long run. 

The most important consideration here 
is weight. Use of four AA-size batteries is 
acceptable, weighing about 170 grams, and 
supplying about 1-5V each (total 6V). The 
balance of the glider is important and the 
battery pack will play an important part in 
the eventual setting up. © 


Model radio control servos are used to 
control the aircraft as these are purpose 
built, lightweight, available at modest 
prices and are designed to be installed into 
model aircraft. Radio control servos 
require a position instruction every 18ms 
and the PIC’s interrupt routine is set to out- 
put this information, irrespective of what 
other tasks are being executed. The servo 
position instruction comprises a Ims start 
pulse followed by a command pulse vary- 
ing between zero and Ims. 

The servos are 3-wire units. The positive 
lead connects to the power supply positive 
line, the earth connects to battery negative, 
and the data line to the appropriate PIC 
output. | 

An analysis was not considered neces- 
sary with regard to the vulnerability of 
each system to the overall stability (and 
therefore safety) of the control system as it 
would be used in a hobbyist setting and not 
for commercial use. 

However, an airbrake could be added 

should the glider remain airborne for too 
long. Readers knowledgeable in PIC 
program writing could easily modify the 
software to drive another servo to control 


Fig.6. Freebird printed circuit board component layout, wiring details to servo motors and 

Completed printed circuit board connected to a single servo motor. Note the four 

attitude tilt switches. 

it. A timer of up to 14 minutes duration 
could be created by counting the 18ms 
interrupts by means of a 16-bit counter. 


The printed circuit board (p.c.b.) assem- 
bly and track layout details are shown in 
Fig.6. This board is available from the EPE 
PCB Service, code 367. Assemble in your 
own preferred order, noting the direction of 
the diodes and capacitor C3. Use a socket 
for the PIC. 

Identify the common lead (it has a spot 
alongside) on the s.i.l. resistor module and 
position it as shown. Note that p.c.b. holes 

3-0IN (76-2mm) 

full-size copper foil underside master pattern. 

Everyday Practical Electronics, September 2002 

have not been provided for the unused 
resistors in the module. The unrequired 
leads should be folded back to allow the 
module to slot into the p.c.b. 

Install the tilt switches with plenty of 
curvature in the leads — this will make later 
adjustments easier. 

Make sure the d.i.l. switch is soldered in 
correctly (i.e. the switch should be closed 
when at the top of the bank, and off at the 

After you have fully checked the cor- 
rectness of your soldering and assembly, 
and confirmed that the power supply is cor- 
rectly working, insert the preprogrammed 
PIC into its socket, ensuring its 
correct orientation. If you have 
your own PIC programming facili- 
ty, such as the EPE Toolkit 
MK3/TK3 programmer, the PIC 
could be programmed in situ. See 
this month’s Shoptalk page for 
details of obtaining the software 
and preprogrammed PICs. 

Note that the programming - 
pinouts of the TB1 connector do 
not correspond to the “standard” 
John Becker arrangement. 

Do not connect the servos to the 
p.c.b. until after the following ini- 
tial setting up. 


Place the assembled p.c.b. on a 
flat table and ensure that switch S5 
(Servo Lock) is selected to dis- 
abled (i.e. all servos unlocked). 
Physically adjust the vertical angle 
of the tilt switches until all the 
l.e.d.s are just out. Raise the free 
end of the bent over tilt switch to 
turn it on earlier, lower to turn it off 

To check the Pitch setting, raise 
the rear of the board by approxi- 
mately 10mm until tilt switch S1 
and |.e.d. D1 just turn on. Return 

1-6IN (40-7mm) 







Fig.7. General arrangement of 
servos within the glider. 

the board to horizontal and then raise its 
front by about 10mm, to check switch S2 
and l.e.d. D2. 

To check the Roll setting, lift the left 
edge of the board (i.e. bank to the right) 
and check tilt switch S4 until l.e.d. D4 just 
lights. Repeat for left banking. 

Connect up the yaw servo. Check that 
this servo responds to right and left roll. 
Then connect up the Pitch and Roll servos 
(omit the roll servo if desired — see later). 
Mark each servo with labels stating 
“Elevator” (pitch, RA2), “Aileron” (roll, 
RA3) and “Rudder” (yaw, RA4). Check 
that all of the mode slide switches (S5 to 
S8) operate correctly. 

Freebird is now ready for installation 
into a glider. 


More experienced model makers may 
wish to build their own glider specifically 
for the job. For those new to flying “free 
flight” model gliders, purchasing a partial- 
ly completed model is recommended, 
which only requires minor additions for 

For the novice, the subject of model 
gliders and how to fly them is quite exten- 
sive, but with a little patience, an enquiring 
mind and a will to “tinker”, there is no rea- 
son why a reasonably good glider, with 
adequate flight characteristics cannot be 
built. Joining a club will be of great benefit 
to the novice. 

With the prototype installation, using a 
NiCad battery pack and three servos, the 
weights were as follows: 

Battery pack 150gms 
Freebird p.c.b. 30gms 
Servos 150gms (total) 

Adding a little for linkages, nuts and 
bolts, the total payload weight was about 
350gms. The servos used for initial tests 
were far heavier than necessary and were 
later replaced with “micro servos”, reduc- 
ing the weight by 80gms. 






The — glider 
requires to not only 
lift itself, but also the 
payload, plus a little for 
luck. It all gets a little com- 
plicated now and you are 
best advised to ask your local 
model hobby store to recommend a 
glider. Tell them you need something 
suitable for a novice to build, the 
payload will be 350gms, with a low wing 

For good stability, look to acquire a glid- 
er with a “double dihedral” wing. 

Fix the wings to the fuselage using sev- 
eral large overlapping rubber bands. This 
helps to absorb the shock when landing on 
a wing, which is a common event, although 
it is reduced as Freebird becomes more 


The model must balance correctly in the 
pitch and roll axes. The balance point for 
pitch should be one-quarter to one-third of 
the width of the wing back from the lead- 
ing edge. Position batteries or a dummy 
weight to obtain this balance point. 

Check that the model balances also in the 
roll axis, by supporting each end of the fuse- 
lage centre line with pins. Check to see 
which direction the glider rolls. Use PVC 
tape or some coats of dope (model paint) on 
one wing as counterweights to correct as 
much as possible, although perfect balance 
in this axis is not really possible. 

Note that Freebird is not sophisticated 
enough to enable a poorly constructed and 
set-up glider to fly, but it will extend the 
flight of a reasonably well set-up glider. 

When selecting a glider, remember to 
check that the wings are detachable and 
that all the various parts will go through a 

car door. Access to the p.c.b. will be neces- 
sary to allow different software modules to 
be selected via the switch. This nor- 
mally will require the wings to be taken 
off. If you intend to carry out “in the field” 
programming, check that a small hole can 
be made in the fuselage for the program- 
ming connector. 

The first objective should be to obtain a 
good understanding of a free flight glider 

_ by making a series of flights with the glid- 

er loaded up with equivalent weight of bat- 
teries and servos. Learn how to note the 
weather conditions, how to check the bal- 
ance, and how to launch. 

Finally, learn how to note each flight and 
the correction(s) (make only one at a time) 
necessary to slowly improve the flight 
time. Breakages and how to fix them on the 
hills will become second nature! 


The flight of the glider is corrected by 
means of a moving rudder, ailerons and 
elevators in exactly the same way that full 
size aircraft are controlled, see Fig.7. The 
servos connect to the control surfaces by 
means of thin “push rods” or Bowden cable 
— most good model shops will stock such 

The direction of travel of the servos is 
important to note, but more on that later. 
With the battery installed in the nose of the 
glider, the servos are all mounted in the 
fuselage, usually somewhere under the 
wing so that the glider balances, when held 
by the wing tips. 

The aileron servo is mounted in the. 
wing and this can be a little tricky for 
those new to model glider con- 
struction. The servo linkages 
should be arranged to deflect 
each aileron in the opposite 
direction (i.e. left up, 
right down), but they 
should both return to 
neutral. To ease 
this problem, 
"it 1S possi- 
ble to fly 

Positioning of the circuit board, servos 
and battery (nose cone) in the fuse- 
lage sections. 

Freebird using only two servos (elevator 
and rudder) although correction of roll is 
not as effective. 

Each control surface will require a dif- 
ferent degree of movement to adjust the 
flight of the glider, but a surprisingly small 
change can have a significant effect. 
Normally, the control surface needs to only 
move about 10 degrees above or below the 
horizontal to have an effect on flight 

The surface area of the control and the 
speed of flight also have an impact upon 
the amount of travel necessary. Make use 
of the servo lock mode to view the travel 
distances and check the neutral point of 
each surface is exactly in the centre of trav- 
el. Add small offsets in the lookup tables to 
correct minor errors, or adjust the travel at 

Everyday Practical Electronics, September 2002 

the servo arm. Also, most servo arms can 
be removed and repositioned to extend the 
range of convenient positions. 


Note the direction of travel of each servo 
and check that the movement will alter the 
control surface in the correct direction. If 
the direction of travel is incorrect, swap to 
the other side of the servo control arm, or 
rotate the servo 180 degrees in the aircraft, 
or change the linkage to the control sur- 
face. Ensure that all of the movements are 
correct, before installing the servos, as 
making changes after installation in the 
glider is difficult and time wasting. 

Ensure that some adjustment can be 
made to the servo travel (normally done 

- with a small brass threaded screw connect- 

ed to the servo drive disc, again available 
from model shops). If a PIC programmer is 
available then simply adjust the zero point 
in the “look-up” table. 

Position the battery unit into the front of 
the glider. The glider should balance when 

__ held by the wing one-third of the way from_ 

the leading edge — check this and adjust the 
battery pack as necessary. Locate the bat- 
tery pack with balsa wood and sponge to 
act as a shock absorber. 

Connect up push rods or cables to the 
control surfaces. Install the p.c.b. (tilt 
switch §2 points aft (tail)) in the fuselage, 
under the wings and on the floor of the 
glider. Check that access to the program- 
ming socket is clear. Check that with the 
wings level and the fuselage level all l.e.d.s 
are off — readjust as necessary. If the servos 
are moving all the time, then they can be 
locked using slide switch S5. 

Locate and bolt the p.c.b. into the glider 

and use a hot-melt gun to finally fix the tilt 
switches onto the PCB. It may be neces- 
sary to hot-glue any connectors, as the 
author has sometimes found them discon- 
nected after forceful landings. 


The software is written with simplicity 
and the expectation is that it will prompt 
experimentation, modification and 
improvement. | 

The core of the software is centred 
around the PIC TMRO timer. This is set to 
interrupt the mainline every 13ms thus 
ensuring that the servos are serviced with 
their control pulses irrespective of the other 
things going on. The interrupt code outputs 
to each servo a Ims start pulse followed a 
command pulse of between lms and 2ms 

When the program is not executing an 
interrupt, it is constrained to constantly 
execute the mainline loop. The mainline 
undertakes three tasks: 

l. read mode switches and execute the 
appropriate software module 

2. read tilt switches 

3. calculate required position of all servos 
and load the demand variable, in readi- 
ness for the interrupt to output it. 

Three variables define servo demand: 
servop — pitch servo position 
servor — roll servo position 

servoy — yaw Servo position 

Flight correction table for Pitch: 

Flight Attitude Sensor values corrective elevator 
; D1 Ul servop value degrees 
Level flight 1 1 125 0 
10 deg pitch down - 1 0O 187 10 up elevator 
10 deg pitch up 0 1 62 5 down elevator 
Inverted flight 0 O n/a n/a 
Flight correction table for Roll: 
Flight Attitude Sensor Values Corrective Aileron 
Li Rl servop value degrees 
Level flight 1 1 125 0 
10° roll left 1 O 187 5 right aileron 
10° roll right 0 1 62 —5 left aileron 
Inverted flight 0 O n/a 0 n/a 
Flight correction table for Yaw: 
Flight Attitude Sensor Values Corrective Rudder 
| L1 Di R1 U1 servoy value degrees 
level flight 1 11 1 » 125 0 centre 
10° roll left, only Oo 1 1 41 187 15 night 
10° roll right, only rtoid 62 —15 left 
10° roll left, pitthdown 0 O 1 1 250 30 right 
10° roll right, pitthdown 1 0 O 1 0 —30 left 
10° roll left, pitch up ——_90 1-1-0 .——-187-—— 15 right 
10° roll right, pitch up 1 1 0 0 © 42 —15 left 
Inverted flight 0 0 0 0 125 0 centre 
Error 1 1 0 0 125 0 
Error 0 01 1 125 0 

A servo position is determined by the 
value placed in any of the variables above. 
Five positions for the pitch servo are given 
below. The current servo position is held in 
the variable servpe and is used where a 
slower rate of movement has been selected. 

Servop (decimal) Servo degrees 


65 —15 
je 0 

187 +15 

250 +30 

The rate of travel of the servos can be 

~ adjusted by means of the mode switch. The 

demand position is subtracted from the 

- current position to give an error value and 
the servo is instructed to move in the direc- 

tion so as to reduce the error to zero. 

Freebird can operate a fourth (auxiliary) 
servo. This could be used to operate air 
brakes, after a period of time for example. 
As said earlier, one way to devise a timer 
could be to use the 18ms interrupt to incre- 
ment a 16-bit counter. This would give 
timed periods in excess of 15 minutes. 

It is possible for Freebird to detect invert- 
ed flight, but correction of this extreme situ- 
ation has not been implemented. 

New and experimental code can be pro- 
grammed into the PIC either at home, or on 
the hillside and then tried out. The mode 
switches can be reprogrammed for this task 
if required. 

The attitude sensors are defined as: 


U1 forward sensor (senses 10° pitch 

D1 aft sensor (senses 10° pitch down) 


Li right sensor (senses 10° roll left) 
Rl left sensor (senses 10° roll right) 

not present (computed response) 

Everyday Practical Electronics, September 2002 


Take care when selecting the launch site. 
Avoid crowded areas and places where the 
glider might stray into traffic. Make sure 
that access to the site has been approved 
and preferably fly with a club. The follow- 
ing list of equipment that can be put into a 
rucksack may be useful for the indepen- 
dent flyer. 

Notepad and pen 

Small selection of Balsa and glue 

Tissue paper, dope, cleaner and brush 
(for covering holes in the tissue covering) 

‘Selection of trimming weights (nuts and 

Spare set of batteries 

Pliers, screwdriver 


PVC Duct Tape 

Sunglasses, blanket, sandwiches, flask 
of coffee! 

Choose a sight with a 180 degree unob- 
structed field of view (i.e. no trees, styles 
or fences etc) combined with a good slope 
of about 30 or 40 per cent. For initial glide 
testing, try to find a field with long grass — 
this makes a good cushion. 

For the first flight, unlock the servos and 
set pitch and roll to maximum travel and 
response rate to fast. Tilt the glider and 
check that each control surface moves in 
the correct direction. Recheck the glider 
balance, under the wing tips. 

Launch the glider into wind whenever 
possible. Try to avoid gusty conditions at 
first. Do not launch the glider upwards — 
this will result in a stall. What the glider 
initially requires is airspeed, so launch the 
glider horizontally. It will initially drop 
quickly until airspeed is gained and then it 
will then slow down and settle into stable 

As soon as possible note what the glider 
does. If it pitches up and stalls, set a little 
more down elevator. Take your time in 
between flights — think about what hap- 
pened. Trace the flight path with your hand 
to reinforce the complexities in your mind 


Using a spirit level to check fuselage “balance”. 

— what needs to be corrected? It can be 
several motions combined — try correcting 
one motion or problem at a time. Check the 
balance every time the glider is prepared 
for a launch. 


Note that flying gliders that have pro- 
nounced flight duration requires fliers to 
give extra consideration to safety. Keep 
models to a wing span of less then 90cm. 
Avoid flying near roads where car dri- 
vers might be distracted or in crowded 
parks. If you find a field, gain permis- 
sion from the farmer or owner — these 
are small considerations and adhering to 
them will enable gliders to be enjoyed 
by everyone. 

balance wings. 

Try to join your local model flying club, 
where you will find a wealth of experience and 
talented people, added to the fact you should 
be covered by a club flying insurance policy. 
Under no circumstances should Freebird 
be used in power models of any sort. 

Be aware that bad landings and various 
forms of breakages are a natural part of 
experimenting with free flying models and 
these should be seen as an inevitable part 
of investigating flying machines, rather 
than a major catastrophe. Patch them up 
and get them back into the air. 

If you think that seeing your model with 
a broken wing on the first flight might 
tempt you to jump off the hill in despair, 
then this pastime is not for you. 

The best of luck to those of you that 

Using several coats of dope (model paint) to counter- 

might be tempted to build Freebird 
and venture out onto the hills this 
summer. [ ] 

References | 
Basic Aeronautics for Modellers, 
Alasdair Sutherland, Traplet Publications 
ISBN 0 9510589 4 0 
Designing Model Aircraft, Peter Miller, 
Traplet Publications ISBN 0 9510589 6 7 
British Model Flying Association: 

‘ — all sorts of informa- 

tion about clubs etc. 
Radio Controlled Soaring: www. — gliders, gear, events. 
Traplet Publications: 
— Quiet Flight gliding and electric flight 
magazines, designing and building aircraft. 



Temperature control range 65 - 450°C 
Thumb wheel potentiometer control 
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Post Free to UK addresses. 


Temperature control range 65 - 450°C 
Digital readout temperature control 
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Wide range of spare bits (0.5mm - 6.0mm) 

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Everyday Practical Electronics, September 2002 

A roundup of the latest Everyday 

News from the world of 



Barry Fox reports on how many World Cup fans felt 
squeezed out of the picture. 

CREEN Digest estimates that one in 

three large screen TV sets now bought 
in major European markets has a 16:9 
widescreen. Dealers who saw the World 
Cup as a nice way to sell more sets were 
shocked to find the broadcasts were in 4:3 
only. So were viewers who expected to see 
the full spread of the pitch. 

Some fans were seeing short fat players 
because widescreen sets will often auto- 
matically stretch ordinary 4:3 pictures to 
fill a 16:9 screen. The broadcasters are still 
passing the buck and say only that they 
hope for better pictures next time in 2006. 

The Dixons group had to pull a page 
from its web site which promised cus- 
tomers they would “see more of the world 
cup action on a widescreen television”. 
“Mercifully,’ says a spokeswoman, “we 
hadn’t put out a press release”. Said a 
spokeswoman for the commercial ITV net- 
work: “We’ve had lots of calls from view- 
ers wanting widescreen. It’s a shame. It’s a 
pity. But that’s the way it is. We wanted to 
show the matches in widescreen but there’s 
only one feed. And it’s the same for ITV 
and the BBC”. 

Offside Passing? 

The BBC had a prepared statement 
which claimed only 4:3 pictures are avail- 
able from the satellite links, and blamed 
FIFA. FIFA pointed the finger at Host 

Broadcast Services, the Swiss-based com- 

pany formed in 1999 to send World Cup 
pictures round the world. “It is not correct 
to say that the format of the TV produc- 
tion of FIFA WC 2002 is only 4:3”, 
assured Francis Tellier, CEO of HBS 
“although it is correct to say that this is 

the format of the main HBS production. | 

The choice to broadcast 4:3, not 16:9, has 



NOT content with miniaturising the features that fill a given chip area, Sharp have taken 
the idea vertically as well as horizontally. Their latest development effectively stacks four 
chips on top of each other, all in the same package. 

Sharp point out that “integration in the third 
technical advantages: various chips from different production processes can be combined 
to provide a system solution within one casing, without having to change the shape factor. 
For more information browse 

dimension”, i.e. vertically, offers substantial 

been made by the broadcast partners, not 
FIFA or HBS”. 

HBS was using two completely separate 
camera teams. One was shooting all 64 
matches with 4:3 pictures, in the 525 line 
NTSC format used for everyday broadcast- 
ing in Japan and Korea; the other camera 
crews were covering only 48 matches and 
using widescreen cameras in the 1125 line 
high definition system used for some satel- 
lite services in the Far East. Although it is 
technically possible to convert the 1125 
line pictures to 525 line NTSC, and to 625 
line PAL for Europe and Australia, no 
country in the world was doing this. 

Out of Touch 

The two camera teams were working 
completely separately so the pictures and 
views they provided were quite different 
and needed different commentaries. Also 
the widescreen pictures were not being shot 
with “protection” to ensure that vital action 

across the pitch is kept in the middle of the © 

widescreen pictures. So a vital kick at the 

side of a 16:9 screen would have been lost 

off the edges of an ordinary 4:3 TV set. 
Moreover, the widescreen teams did not 

have the exotic slow motion equipment 

used for instant replay on the 4:3 feeds. 
Also, it costs local broadcasters more to 
bring in both sets of pictures by satellite 
and give viewers a choice. As a result only 
Japan and Korea bought the widescreen 

Engineers inside the BBC have privately 
admitted to inadequate forward planning 
and accept they should do better next time. 
Pressure from viewers will count. Francis 
Tellier says HBS will re-think its policy for 
FIFA WC 2006 Germany “‘in light of the 
opinion of our broadcasters”. 

Everyday Practical Electronics, September 2002 


TO QUOTE their press_ release, 
“Meterman digital multimeters and test 
tools were designed for use in design, 
evaluation, installation, production, serv- 
ice and troubleshooting of electronic and 
electrical equipment and systems.” 

Meterman are currently offering a 
money-saving compact kit for electronic 
technicians and engineers for a limited 
period. Comprising a Meterman Digital 
Multimeter/Component Tester and a 4- 
way screwdriver, the two products pro- 
vide a convenient troubleshooting kit for 
many electronic applications (what, no 

The 27XT-P meter/tester offers 11 func- 
tions, a 2000 count, data hold/max hold 
and auto power-off features, fused cur- 
rent input and 0-5% basic accuracy. With 
category Il safety compliance, it meas- 
ures a.c./d.c. voltage and current, fre- 
quency, capacitance and inductance, 
resistance, continuity, and has a diode 
test facility. It also tests for TTL or CMOS 
logic. The heavy-duty screwdriver has 2 x 
Philips and 2 x flat-headed removable 
bits. The kit is available at the special 
price of £72 until the end of November 
this year. For more information about the 
full range of Meterman test tools and 
where they can be purchased, visit, email: info@ meter | 

FML Bargains List 

WHEN looking for bargain components, 
don’t forget to include FML Electronics on 
your list — we’ve just received their latest 
double-sided sheet of bargain offers, cov- 
ering batteries through to transformers, and 
they obviously have many competitive 
prices. Their 2003 catalogue is said to be © 
“available shortly” and you only need to 
send an s.a.e. if you want a copy. 

For more information contact FML 
Electronics, Dept. EPE, The Business 
Centre, Bridge Street, Bedale, N.Yorks 
DL8 2AD. Tel: 01677 425840. 

Email: bargains.fml 





MICROCHIP Technology, manufacturers of the PIC microcontrollers that we feature so 
frequently in our constructional designs, have released their Technical Library CD-ROM 
2002. It comprises two CDs that feature a snapshot of Microchip’s newly designed web- 

site and are viewable with an HTML browser. 

Disk one itemises data for the full Microchip product range, disk two contains the full- 
line of Microchip’s application notes and related source code, development tools and 


EPE gave away the 2001 set of Microchip CDs as a front cover free gift with the October 
2001 issue. However, even if you already have that information, it is still worthwhile ask- 

ing Microchip for their latest CD set. 

For more information on obtaining this CD-ROM set, browse 


TWO new retractable test tip probes have 
been introduced by Pomona Electronics. 
They are designed specifically to test and 
measure electronic components in tight 
spaces with limited access, and feature a 
hardened stainless steel tip that pene- 
trates conformal coatings, painting and 

The tip can extend up to 7-7cm, is fully 
insulated and has 1-2 metre leads that fit 
most meters, including Fluke, Meterman, 
Agilent, Amprobe and Greenlee. 

For information on Pomona’s test acces- 
sories, or to order a copy of their catalogue, 
contact Pomona Electronics Europe, Dept. 
EPE, PO Box 1186, 5602 BD Eindhoven, 
Netherlands, or visit 


“The stork has landed!” states a press release from Urathon, 
continuing: “Urathon are pleased to announce the arrival of the 
Car Baby — one cute baby that won’t tug at your purse strings, 
and you will love it for ever with hardly a gurgle and certainly 

never a scream”. 

Whatever your feelings about such expressions, Car Baby 
converts your mobile phone into a hands-free set with no wires 
and no earpiece. It is compatible with all makes of mobile, with 
no conversion kit, clipping over your mobile and sending the 
caller's voice to your car’s radio and speaker. Conference calls 
are said to be easy, as the unit picks up the voices of everyone 

in the car. 

Car Baby costs £24.95, including VAT, and is available from 
Urathon Europe Ltd., Dept. EPE, Thane House, Hilmarton, Wilts 
SN11 8SB. Tel: 01249 760581. Fax: 01249 760547. Email: 



DIGITAL photographers, Barry Fox tells 
us, Can now instantly jump closer to their 
subject, without moving an inch, and with- 
out any loss of picture quality. Panasonic’s 
Tele-Jump exploits the fact that the ‘CCD 
image sensor in a modern camcorder is 
designed for capturing still pictures on a 
memory card, as well as moving pictures on 
tape. The sensor has a matrix of 1024 x 768 
pixels which gives the clarity needed for 
stills. This is too much for movie tape, so 
the image must be electronically downgrad- 
ed to 720 x 576 pixels for moving pictures. 

Pushing the new Tele-Jump button uses 
only the central area of the sensor, 720 x 
576 pixels in size, without any downgrad- 
ing. So a head and shoulders shot instantly 
zooms to a face-only picture. 

Magtrix Connectors 

‘For Batteries, PCBs 
and Electronics” 
Send for leaflet Today 

Tel: 01254 830761 Fax: 01254 830408 

By Barry Fox | 

YOU have until September 15th to get on 
down to the Barbican Gallery in London 
and — provided you can find your way to, 
from and around the appallingly badly 
signposted Barbican area maze — enjoy 
Game On: The Culture and History of 
Video Games. Admission is £11, 
Concessions £8, Children 5-15 years £5, 
Under fives free. 

The organisers advise advance booking, 
with timed tickets; it is easy to see why. 
They have brought together an astonishing 
collection of original games hardware and 
are giving visitors the chance to play on it. 
In all there are 150 arcade and home game 
consoles, and although gamers are asked to 
limit play to 15 minutes, the whole point of 
the exhibition will be lost if visitor num- 
bers are not restricted. 

It’s hard to believe that computer game 
history dawned only forty years ago, when 

» Steve Russell at MIT used paper tape to 

make a DEC PDP-1 play Spacewar. The 
real revolution began in 1971 with arcade 
games Computer Space and Atari’s Pong. 
The first home console, the Philips’ 
Magnavox Odyssey, went on sale in 1972. 
Space Invaders arrived in 1978 and Pac- 
man in 1980, followed by a deluge of old 
favourites from Atari, Sinclair, 
Commodore, Nintendo and Sega, with 
Donkey Kong and Sonic the Hedgehog. 

All are up and running at the Barbican, 
some with original consoles, sometimes 
with ruggedised controls, and a few on 
large screen projectors. There’s a look at 
the violence of Grand Theft Audio and the 
theory behind strategy games like Sim City. 
Sections on sound, storyboard scripting 
and hand-held portables lead on to a look 
at the future with Liquid Fire, a game that 
uses motion sensors to track a player’s 
hand and body movements. 

The organisers are going to have their 
work cut out keeping all the hardware 
working, but most visitors seem to be treat- 
ing the equipment with reverence. Even 
people (like me) who cannot get excited 
about video and computer games, this is a 
superb exhibition. And it reminded me of 
an oddity which I must now try and 
unearth from my attic; a very early hand- 
held tennis game from Japan that used a 
clockwork drive to flip little lights on 
spring wires across a translucent screen. 

Everyday Practical Electronics, September 2002 


Loe ege LOO 

Oe ek ee ee 

Serial Alphanumeric and Graphic Displays, 
Mini-Terminals and Bezel kits 


3-Axis Machine 


sine a Se tee 

— Quadravox Sensoryinc | | _ Partllax | |. Tecrick _ BASICMicro 
MP3 & Speech Systems Voice Recognition | Ubicom Tool Kits | | PIC & Rom Emulators PIC BASIC Compilers 

Development Tools 

Milford Instruments Limited Tel 01977 683665, Fax 01977 681465, sales 

Regular Clinic 

_ SURGER yy 


Our team of monthly surgeons revisit Darlington transistors and the Sziklai connection, 
plus a roundup from our postbag on the topic of soldering. 

Back to Darlington 

In the June 2002 issue of Circuit Surgery 
we briefly described the Darlington tran- 
sistor and similar configurations, which 
use two transistors to obtain a transistor 
action with higher gain and/or input 
impedance than is available from a single 

Perhaps we were a little too brief, as 
reader Ron Harrison pointed out in an 
email to us. The second configuration in 
Fig.3 in that article (page 439) is a com- 
pound pnp transistor and illustrated a vari- 
ation of the Darlington theme that was not 
actually described in the text, which may 
have been a little misleading. 





TR2 — TR2 
TR1 TR1 
B B 
C) D) 
E E 


To make matters worse the labelling of 
the effective emitter and collector connec- 
tions was incorrect in that figure! The 
emitter and collector labels should be 
transposed in the right-hand configuration 
given. | 

To help overcome any confusion, in 
Fig.1 this month we show both npn and 
pnp versions (a) and (b) respectively, of 
both the Darlington, and the other less well 
known compound transistor configurations 
(c) and (d). 

Sziklai Pair 

We will take a more detailed look at this 
latter transistor pair, as readers may be less 
familiar with it than 
the Darlington pair. 
One of the main fea- 
tures of this alternative 
compound transistor — 
which is known as 
a Sziklai pair or 




Fig.1 (above). 
Darlington and 
Sziklai Pairs (or 

Fig.2 (left). CFP 
with bias resistor. 

Fig.3 (right). CFP 
used in power 
amplifier output 

Feedback Pair (CFP) — is that it only 
requires a single Vpr voltage to turn on, 
unlike the Darlington which has an effective 
Vpg equal to two Vpr drops. 

Therefore, the Sziklai has the advantage 
of being able to be “plugged in” in place of 
a single transistor, and the lower effective 
Vp does not compromise its use in low 
voltage circuits (an important concern in 
modern chip design). The CFP also has 
lower output resistance than _ the 
Darlington, about one tenth of the value 
when used in a common-emitter-style 
configuration under the same quiescent 

The CFP is. typically biased using a 
resistor as shown in Fig.2, where R1 is 
selected so that most of the current in TR1 
flows through R1 rather than the base of 
TR2. This means that the quiescent current 
in TR1 is well defined and does not depend 
on the gain of TR2 and its collector cur- 
rent. The collector current of TR1, Ic, is 
approximately Vpr/R1 if we assume that 


Everyday Practical Electronics, September 2002 

TR2 has a high enough gain for Ip, to be 
significantly smaller than Ic. 
Typically we want TR1 to have a quies- 

cent current about one tenth of that of TR2 — 

so, given this assumption, and given that 
we probably choose Ic) as a key design 
parameter, we get 

R1 = 10V pF /I, 

where as usual Vpr. would typically be 
between 0-6V and 0-7V. 

CFP Amp 

A typical use of the CFP is in audio 
power amplifier output stages where it 
delivers better (at least according to its 
proponents) performance in terms of ther- 
mal stability and large signal non-linearity 
due to the feedback effects within the tran- 
sistors pairs (hence the CFP name), 

although these effects are reduced at high | 


In Fig.3 we show the schematic of a typ- 
ical power amplifier output stage based on 
the CFP in which the transistor pairs are 
used in the same way as a standard push- 
pull emitter follower output stage. The pair 
TR1-TR2 handles the positive half of the 
signal, and the pair TR3-TR4 handles the 
negative half. The bias circuit ensures that 
the transistors switch on for the correct part 
of the signal waveform (for example to 
prevent crossover distortion). 

The pnp Sziklai pair has played a role in 
integrated circuit design for a long time, 
particularly in essentially npn processes 
that allowed fabrication of good npn tran- 
sistors, but which only provided low gain 
pnps. The compound transistor provides a 
means of obtaining a high-gain pnp in 
these technologies. 

You may be interested to know that the 
use of enhanced transistors built from more 
than one transistor does not stop at the con- 
figurations discussed here. For example, in 
1990 Bult and Geelen published a design 
of an op.amp built using high performance 
““Super-MOS” transistors. The Super-MOS 
is a circuit which is built from no less than 
12 ordinary MOS transistors, but behaves 
like a very high gain MOSFET which is 
also “self biasing” and therefore easy to 
use. IMB. 

Soldering Tips 

One of the joys of hosting the world’s 
most popular Internet guide on soldering 
faq.htm) is the great diversity of questions 
that arrive by email. Soldering is of course 
not confined to electronics — many other 
materials are soldered as well, from brass 
Tiffany lamps to the refrigeration piping of 
a cooler being restored in a Greyhound 
bus! A lot of time is spent behind the 
scenes at Circuit Surgery trying to help 
correspondents all around the world with 
their soldering techniques, and here are a 
few recent items from the EPE mailbag — 
as you'll read, we may not always know 
the answer but we will try to give some 

I am working on the Scottish Parliament 
building using 0-5mm Low Lustre Stainless 
Steel Longstrip sheeting and I have to sol- 
der some joints. I would like to know the 
life expectancy of soldering and I wonder if 

_ fatigue to the soldering. , 

you could advise or point me in the right 
direction where I can get information on 

: this. TM by email. 

I checked for suitable solder on Multicore suggest a 
Tin-Silver solder (Sn/Ag 96-5/3-5) only, 
together with an inorganic acid flux or sol- 
der paste e.g. AC10 would be suitable for 
use with stainless steel. Electronics solder 

has built-in flux to help it flow, but in other 
- industries, a separate flux paste is applied. 

Never should you need to apply acid flux 
when soldering electronic components! 
What I’m not sure about is the longevity 
of the soldering in this application. If it’s 
external then it is likely to be affected by 
pollution (acid rain, caustic cleaners etc.), 
also any mechanical flexing will cause 

The expansion of metal 
in heat might give rise 
to this. I know that dis- 
similar metals in con- 
tact with salts will give 
rise to corrosion, and I 
know that different 
grades of stainless steel 
will be adversely 
affected by _ this. 
Contrary to popular 
belief, stainless steel 


can be attacked by A benchtop fume extractor contains a fan which draws the 

and will blithely work into the night, inhal- 
ing solder fumes, dealing with ferric chlo- 
ride etchant, handling lead-tin solder and 
generally having a great time in the 

One item I always suggest for anyone 
keenly interested in electronics, is a 
bench-top solder extractor to duct irritat- 
ing fumes away from the eyes and nose 
(see photos). They contain an activated 
charcoal filter to neutralise the fumes. 
Without doubt, fumes from melting 
rosin-filled solder can be highly irritat- 
ing, and I know of some engineers who 
are sensitive to this form of irritation, 
perhaps having formed an allergy. One 
correspondent uses an old cylinder 
vacuum cleaner with along hose that 
suck fumes away from the bench. ARW. 

chemicals and there are fumes through a charcoal filter and away from the work area. 

steel available to —«— 
counter this problem. If it is indoors then 
the material is likely to last for decades but 
if your work has to brave the Scottish 
weather then I’m not sure. 

I suggest you start by contacting CIBSE, 

_ the Chartered Institution of Building 

Engineers who may 
be able to point you to a specialist or con- 
sultant or another organisation. ARW. 

Defense de fumer 

I read your online soldering guide and I 
have a question which I really hope you 
can answer. You said that solder contains 
about 60% lead, well I’m_ using 
Radioshack “High-Tech  Rosin-Core 
Solder” and I had an incident with it when 
I was working with it for five hours straight 
and I got REALLY sick, I had to be taken to 
the hospital and was out of commission for 
a week. Now when I solder, I use a 3M res- 
pirator designed for painting, I don’t real- 
ly know it that blocks the fumes though, do 

you know anything about this? GZ by — 


You are totally right to take any sensible 
precautions, though wearing a respirator is 
not something I’ve seen in this application, 
as it would be too unwieldy. There are dif- 
ferent types of filter cartridges available for 
use against e.g. organic vapors or solvents, 
and solvent-proof filters and suitable 
masks are available from larger DIY 

You may be very sensitive to the fumes 
given off by the smoking flux. In the UK 
and the USA there are very strict regula- 
tions on exposure to chemicals and fumes 
in the workplace. A manufacturer’s materi- 
als safety data sheet (MSDS) offers guid- 
ance in relation to the safe use of their 
products. At home though, hobbyist con- 
structors work under no such restrictions 

Everyday Practical Electronics, September 2002 

grades of They have a “range” of about 12 inches or so. 

The best solder wire 

I have visited your web site and found it 
very interesting. There is lot of info 
regarding soldering, a very nice site. I 
want to know which type of solder wire is 
good for professional use. I mean 60/40 
type, eutectic 63/37 or NO CLEAN type. 
Please advise me the best solder wire. Arif 
Deshmukh by email. 

It depends on what you’re trying to sol- 
der. “Best” depends on the criteria — cost? 
reliability? efficiency? A good place for 
advice is who make 
a wide range of solder wire which is sold 
through all the major distributors. 
Personally I use 60/40 tin/lead for all my 
hand soldering. Some engineers use silver 
solder or “Smart Wire” for the best possi- 
ble finish by hand. 

The combination of metals used in the 
alloy also affects the price. You can buy 
60/ 40 or 40/ 60 tin/lead, the latter being 
somewhat cheaper. A quick look on the 
London Metal Exchange at today’s prices 
reveals why: lead costs $454 per tonne but 
tin costs ten times more at $4,425 per 
tonne. Copper costs $1,606 per tonne if 
anyone’s interested (no circuit should be 
without some). 

Coming to an electronics workbench 
near you sooner rather than later, is the 
prospect of lead-free solder, which may 
well become compulsory in due course for 
environmental reasons (it already is, in the 
plumbing industry). It typically contains 
99-7% tin and 0-3% copper and weight for 
weight it is double the price of 60/40 sol- 
der. I have had very mixed reports about 
the use of lead-free solder in electronics, 
and it’s a topic I will be covering in the 
future. Feedback on this from readers 
would be welcomed. ARW 


Constructional Project 



Make the right call with this low-cost, 
easy-to-use, telephone checker | 

EN looking around car boot 
sales, radio rallies etc. you will 
often see telephones for sale. 
They can be second-hand, new or surplus 
stock and since they do not have a guaran- 
tee there is always a risk when buying 
them that they may be faulty. Until now 
there has been no easy way to perform a 
basic test on a telephone where a working 
telephone line is not at hand. 

However, the Portable Telephone Tester 
described here will check the basic func- 
tions of a telephone without using a tele- 
phone line, and it is easily portable . It can, 
if you wish, even be used in the middle of 
a field (car boot sale) or anywhere where 
you are likely to find a telephone for sale. 


The occasion that really prompted the 
design of this tester happened when visit- 
ing a radio rally. One of the stalls at the 

RING = (ON) 



“meet” had about a dozen boxes on it, each 
containing quite an unusual type of tele- 
phone. They were priced at £5 each and 
they appeared to be a real bargain — JF they 
were working! The stallholder said that 
they were all OK, but then they always do! 

The purchase of two or three was con- 
templated, but the author could not justify 
taking a chance on what could turn out to 
be a box of scrap metal. Because of this 

only a single phone was bought. 

It turned out to be an excellent telephone 
which has been in constant use to this day. 
It was this incident that made the author 
realise just how useful a portable telephone 
tester would be. ; 

Considerations to be taken into 
account when designing a telephone 
tester are that telephones usually work at 
higher voltages than are generally avail- 
able with portable equipment. In addi- 
tion, the ringing current required is a low 

frequency (approximately 20Hz) high 
voltage alternating current. 

The Portable Telephone Tester uses just 
one 9V (PP3 type) battery which has been 
found to be sufficient for testing speech 
paths and pulse tones. The a.c. ringing cur- 
rent is derived from a two-transistor multi- 
vibrator driving a “reverse connected” 
mains transformer. The whole tester fits 
into an ordinary electrical pattress mount- 
ing box. 


The full circuit diagram for the Portable 
Telephone Tester is shown in Fig.1.When 
the function switch S1 is set to the Test 
position, power is applied to the telephone 
Line socket SK1, contacts 2 and 5. This 
will initially light the l.e.d. D1 indicating 
that the battery supply is present. The l.e.d. 
is a high brightness type since the tester 
will sometimes be used in daylight. 

Fig.1. Complete circuit diagram for the Portable Telephone Tester. 


_ Everyday Practical Electronics, September 2002 

The battery will also provide power for 
the telephone, when plugged in, and 
enables a number of tests to be carried out. 
These are set out in the separate “Using the 
Tester” panel. 

When switch S1 is held in the biased 
Ring position, the multivibrator circuit, 
made up of transistors TR1, TR2 and asso- 
ciated components, is powered up generat- 
ing a high voltage alternating current (a.c.) 
at the output of the “reverse wired” trans- 
former Tl. This is the ringing current 
which is applied across the Line socket 
contacts 3 and 5 to ring the “test” tele- 
phone bell or sounder depending on the 
type of phone being tested. 

Being the “biased” position, releasing 
the switch actuator toggle/dolly will auto- 
matically cause it to spring back to the 
centre-off position, cutting the supply and 
terminating the ringing. 


When the tester is switched to Test it 
will consume 12mA to light le.d. D1. 
With a telephone plugged in and the 
receiver lifted this rises to 35mA to 45mA 
approximately, depending on telephone 
type. When switched to Ring the current 
drawn is 150mA approx., although this 
will typically be for only 1 or 2 seconds. 

The a.c. voltage measured at contacts 3 
and 5 of the Line socket SK1 (i.e. the out- 
put of the transformer T1) will be about 



rad omMmnganrT-—-ctcAr 

Fig.2. Portable Telephone Tester stripboard topside component layout and details 

switched to the a.c. range. With a tele- 

118V a.c. off load, when using a DVM 

phone plugged in, the measured y 
voltage will be around 78V a.c. this , 
will vary slightly depending on the 
phone used. Take care not to touch 
this high voltage. The frequency 
measured should be about 22Hz. 


Most of the components for the 
Portable Telephone Tester are 
mounted on a small piece of strip- 
board, size 30 holes x 12 strips. The 
topside component layout and details 
of breaks required in the underside 

copper tracks are shown in Fig.2. | 

This board accommodates all of the 
components except the power indica- 
tor l.e.d./resistor (R5) and the battery. 
The l.e.d. and resistor are mounted direct- 
ly on the Line socket panel. 

Commence construction by inserting 
and soldering in position the six link wires; 
these can be made up from discarded resis- 
tor leads. This should be followed by the 
p.c.b. mounting transformer as the pin ter- 
minations are located beneath it. The spec- 
ified transformer has pin spacing of 0-2in. 
which should provide an exact fit on the 

Next, the resistors (except, of course, 
R5) and capacitor should be soldered in 
position on the board. The last components 




5 10 15 20 25 


of breaks required in the underside copper tracks. 

Completed circuit board showing the 
mains transformer mounted directly on 

the board. 



| e®eeetveor 


ryday Practical Electronics, September 2002 

to be soldered in place are the two transis- 
tors and care should be taken to check that _ 
they are the right way round (see Fig.2) | 
before introducing the hot soldering iron 

to their leads. 

Finally, multi-coloured stranded leads 
of about 150mm in length should be 
attached to each end of the circuit board 
as indicated in Fig.2. This should also 
include the battery clip leads. This com- 
pletes the circuit board construction and, 
for the moment, it should be put to one 


Resistors See 
R1, R2 100Q (2 off) 
R3, R4 1k (2 off) SHOP 
R5 5600 

All 0-25W 5% metal film TALK 

C1 _ 470n polyester film, 
100V d.c. 


D1 5mm superbright 
red l.e.d. 
TR1,TR2 2ZTX550 medium power 
pnp transistor 
Miscellaneous . 
$1 d.p.d.t. sub-min toggle 

switch, centre off, 
non-locking one way 
and locking the other | 
(On-Off-On (biased)) 
T1 | 3VA min., p.c.b. 
mounting, mains 
transformer: twin 120V 
a.c. primaries; twin 
3 12V a.c. secondaries 
SK1 flush-fitting, BT type, 
secondary line jack, 
with screw terminals 
B1 9V battery (PP3 type), 
with clips and leads 

Stripboard 0-1in. matrix, size 30 holes 
by 12 strips; plastic surface pattress box 
(84mm x 84mm x 46mm depth), single; 
5mm l.e.d. recessed mounting clip; multi- 
strand connecting wire; solder pins; 


r=) (oe) Ma oF- | 6S 

y.Vo) eo) ge) em rex) | 
Guidance Only 

side on the workbench ready for final 
wiring up later. 


We now need to turn our attention to the 
electrical surface mounting box, which, 
together with the Line socket, forms the 
“case” for the Tester unit. Sometimes called 
a 1-Gang Pattress Box, it must be the deep 
type (46mm approx.); any shallower and 
there will be no room for the transformer. 

To enable the stripboard to fit into the 
box any excess plastic moulding inside, 
which looks as though it will be in the way, 
will have to be removed. Different makes 
have different shapes of internal plastic but 
it is necessary to make each of the sides, 
without the screw mountings, reasonably 
flat on the inside. 

Probably the best tool for cutting out any 
protrusions would be an art knife or sharp 
chisel. However, the author used a small one 
inch diameter grinding wheel on an electric 
drill. The only problem with this method is 
that it does create a dust problem. 

Once space has been made for the circuit 
board we need to drill a 6mm dia. hole for 
the test switch S1. This is located in the top 
side-wall as indicated in Fig.3. 

We also need to drill a 8mm dia. hole 
for the l.e.d. mounting clip in the tele- 
phone line socket. The suggested position 
and drilling details for the l.e.d. is also 
shown in Fig.3. The top half of the p.c.b. 

| 42:-5mm —> | << 42:55mm —> | : 


Fig.3. Suggested positioning and drilling details for the test 
switch (left) and (right) power indicator I.e.d. 



The deep pattress electrical surface mounting wall box after 
the necessary internal plastic obstructions have been 


It is worth testing your own telephone at home first to familiarise yourself with the 
tester before taking it out to a radio rally or car boot sale. 

1. Switch to TEST — no phone 

L.E.D. lights (battery indicator) 

2. Plug in telephone — after checking 
that receiver is on rest 

If l.e.d. goes out or very dim this 
suggests short circuit on telephone 

You should hear your own “blow” in 
the receiver speaker. This simple test 
shows that the microphone and receiver 
are working | 

3. L.E.D. remains bright. 
Lift handset and blow into 

Note: If no “blow” is heard when testing unknown telephones try moving 
the handset and telephone cords while continuing to blow into microphone. 
The cords sometimes have intermittent faults that will show up in this test. 

Various tones should be heard 
in the receiver. This confirms that 
the keypad is working. 

4. Press each of the keys on the keypad 
while listening to the receiver 

Note: If no tones occur or a “clicking noise” is heard, check that switch on the 
base of phone is switched to tone (sometimes marked P and T for Pulse and Tone). 
Old telephones may only produce “pulses” and are not suitable for use with tone only 
systems, although they should be OK on the BT network. 

5. Replace handset and switch to RING 

Bell or sounder should ring 

If not — check switch marked On-Off or Hi-Lo on base of phone and repeat test. 
Try the high and low rings to confirm that they both work. 

If it passes all of the above tests you should have a healthy telephone. 


Layout for components in the two-halves of the case. Note 
that the cable-tie around the transformer secures the circuit 
board to the bottom of the surface box. 

Everyday Practical Electronics, September 2002 


When the preparations of the box and 
line socket have been completed, we can 
now proceed with the final assembly and 
wiring up. At this stage it is a good idea to 
OPTIONAL mount the circuit board and biased func- 
ptieter tion switch S1 into the pattress box. In the 

prototype, the circuit board is held in posi- 
tion by looping a cable tie over the board- 
mounted transformer and passing it 
through two holes in the bottom of the box, 
see photographs. 

Before we take the “loose” ends of the 

leads from the board and wire them to 
switch $1 and the Line socket screw termi- 
nals, the l.e.d. D1 and resistor RS need to 
be connected up. The full wiring details are 
shown in Fig.4. 

When wiring the switch make sure that it 
has the correct orientation; biased action to 
the right when viewed from the top of the 
box (see photographs). The wires to the 
switch can be taken through a length 
(20mm approx.) of sleeving (heatshrink 
will do) to keep wiring tidy. When all the 
wiring has been completed and the 
“power” l.e.d. and battery connected up, 
the line socket and the pattress box can be 
screwed together. 

If the finished unit, together with a known 
working phone, passes all the checks out- 
lined in the accompanying Test Panel, you 
now have a “take-it-anywhere” Portable 
Telephone Tester for your next trip to the 


[est] <—=> Lang] 


Fig.4. Interwiring from the circuit board, line socket and the test switch. The switch 
is viewed from the rear as it appears when mounted in the box. 

(printed circuit board) in the specified make room for the l.e.d. and its leads, 
extension type socket is not used, so a without affecting the functioning of the 

small piece can be cut off one corner to socket. 

local car boot sale or Radio Rally. [] 

Tile) Wad TALK 

with David Barrington 

Freebird Glider Control 

Apart from the model glider, the servo motors are the next most 
expensive item required for the Freebird Glider Control project. The 
author obtained his from Maplin (@ 0870 264 6000 or 

- together with custom servo leads and plugs and 
sockets. We understand that the servo motor is a bit big and heavy and 
it might be a good idea to investigate your local model shop to see if they 
have something smaller and lighter. 

If you wish to use the Maplin servos, you should quote order code 
FS35Q and codes GZ87U (lead), GZ93B (skt) and GZ94C (plug). Good 
gliders can be found at 

The author used mercury tilt switches in his glider, but as mercury is is 

such a dangerous and toxic substance, we recommend that they are. 

replaced with non-mercury types. A suitable alternative, “non-mercury”, 
hermetically sealed tilt switch is listed by the above company and can be 
ordered by quoting code DP50E. 

For those readers unable to program their own PICs, a ready-pro- 

grammed PIC16F84A-20 (20MHz) microcontroller can be purchased 
from Magenta Electronics (@ 01283 565435 or www.magenta2000. for the inclusive price of £5.90 each (overseas add £1 p&p). The 
software is available on a 3-5in. PC-compatible disk (EPE Disk 5) from the 
EPE Editorial Office for the sum of £3 each (UK), to cover admin costs (for 
overseas charges see page 691). It is also available Free from the EPE ftp 
site: uk/pub/PICs/Freebird. 

The Freebird printed circuit board is available from the EPE PCB 
Service, code 367 (see page 691). 

EPE Morse Code Reader 

There should not be any problems finding a suitable two-line 16-char- . 

acter per line alphanumeric |.c.d. module for the EPE Morse Code 
Reader as connection details are included for the two “standard” for- 
mats. The one used in the authors model came from Magenta 
Electronics (@ 01283 565435 or and is 
competitively priced. 

For those readers unable to program their own PICs, a ready-pro- 
grammed PIC16F84-4 (4MHz) microcontroller can be purchased from 
Magenta Electronics (see above) for the inclusive price of £5.90 each 
(overseas add £1 p&p). 

The software is available on a 3-5in. PC-compatible disk (EPE Disk 5) 
from the EPE Editorial Office for the sum of £3 each (UK), to cover 
admin costs (for overseas charges see page 691). It is also available for 

Everyday Practical Electronics, September 2002 

FREE download from the EPE ftp site, which is most easily accessed via 
the click-link option at the top of the home page when you enter the main 
web site at On entry to the ftp site take 
the path pub/PICs/Morse, downloading all files within the latter folder. 

If problems arise trying to find a local source for a suitable sub- 
miniature omni-directional electret microphone, both Rapid 
Electronics (@ 01206 751166 or, 
code 35-019 and Maplin (@ 0870 264 6000 or, 
code FS43W, can supply. Take care, they are tricky to solder leads to 
their pads. 

The Morse printed circuit board is obtainable from the EPE PCB 
Service, code 368 (see page 691). 

Portable Telephone Tester 

The electrical pattress or surface mounting box, which makes up one 
half of the Portable Telephone Tester case, should be available from any 
good electrical store. However, it must be the deep type (46mm deep or 
more) if it is to house the transformer and allow the line socket to close 
on the mounting box. The one in the model came from Maplin (@& 0870 
264 6000 or, code ZB40T. 

They also supplied the BT type, flush-fitting, telephone secondary line . 
socket (with screw terminals). This should be ordered as code FJ34M. 
The two-pole sub-miniature centre-off, biased non-locking one way and 
locking the other, switch used in the prototype also came from the 
above-mentioned source, code FHO6G. 

The 3VA miniature, p.c.b. mounting, mains transformer with twin 120V 
a.c. primaries and twin 12V a.c. at 0-12A secondaries was purchased 
from Rapid Electronics (@ 01206 751166 or www.rapidelectronics., code 88-0160. If any readers experience difficulties sourcing the 
medium power ZTX550 60V pnp transistor, it is also stocked by them, 
code 81-0212, and by ESR Electronic Components (@& 0191 251 4363 

One final comment, take care not to touch the “high voltage” pins of 
the transformer when the circuit board is powered up. 

Vinyl To CD Preamplifier 

_ Only a couple of items may cause concern when purchasing compo- 
nents for the Vinyl To CD Preamplifier project. The interlocking, spring- 
loaded, pushbutton switch which mounts directly on the printed circuit 
board (p.c.b.) came from Farnell (@ 0113 263 6311 or www.farnell. 
com), code 733-155. 

The p.c.b. must be housed in an all-metal case to provide some pro- 
tection against hum pick-up. If you wish to use the same case as the 
author, it appears to be from the Maplin aluminium instrument case 
range and is the Blue 212 version, code XY43W. 

The printed circuit board is available from the EPE PCB Service, code 
368 (see page 691). 


~ New Technology 

OOKING to the future there appears to be 

no less change on the horizon as new 
methods and technologies are required to 
keep pace with the increasing requirements 
being placed upon computing technology. 
Current technologies will be able to meet 
the demands for the near future, but new 
and more revolutionary ideas are being 
investigated for the longer term. 

Not all of the technologies being investi- 
gated will come to fruition, but one excit- 
ing development that shows a lot of 
promise is associated with ion trapping. 
Here the interaction between light 
and matter on an atomic scale is 
used as the basic principle of oper- 
ation. By adopting this approach 
revolutionary new developments 
can be made, providing the possi- 
bility for major advances. 

Over the years a number of insti- 
tutions have carried out work in 
this area. This has now been 
brought together and a proposal 
made for a quantum computer. 
Whilst the computer itself has not 
been built and one will not be avail- 
able for many years, the basic 
building blocks are now being tried 
and tested. Researchers from the 
National Institute of Standards 
(NIST), Massachusetts Institute of 
Technology (MIT) and _ the 
University of Michigan have been 
working together and they have 
recently reported their findings in Nature. 

Current computers operate using binary 
numbers and use two states, namely “on” 
or binary 1 and “off” or binary 0 to repre- 
sent numbers. A quantum computer 
makes use of the properties of quantum 
mechanical systems rather than transis- 
tors. Here the everyday principles we all 
know and accept seem not to hold and 
many new and unusual properties seem to 
be present. Those who have studied quan- 
tum mechanics and know of laws such as 
Heisenburg’s Uncertainty Principle may 

Using Quantum Mechanical principles it 
is found that atomic particles can exist in 
several states simultaneously. This is based 
on what is known as the superposition 
principle that indicates that a quantum 
mechanical system such as an atom can 
exist in several energy states or spin direc- 
tions until it is actually measured. 

Bursts of light can flip the bits in vari- 
ous ways, independently changing vari- 
ous values and creating a logic gate that 
enables calculations to proceed down 
many different paths at the same time. 
When a calculation is complete it can be 


Is this the next quantum /eap in computing 
technology? asks lan Poole 

extracted and measured again using light 

This means that they can be used to 
manipulate many times more information 
than would be possible with a traditional 
computer, leading to a major leap on the pro- 
cessing power of such a machine when com- 
pared to what is possible today. Ideas for 
such computers could include performing 
virtually real simulations on the world’s 
weather or many other applications requir- 
ing huge amounts of processing power. 


® \ TRAP 





Fig.1. A form of ion trap 

lon trap | 

The basic building block of the computer 
would be an ion trap. These traps are places 
where ions can be stored, observed and 
manipulated. Whilst the possibility exists of 
manipulating large numbers of ions in each 
trap, this currently presents immense tech- 
nical difficulties. Nevertheless it is feasible 
to use tens of ions in each trap. 

The Quantum Computer or QC itself 
would be built from a number of traps and 
the research team called the architecture a 
“quantum charge coupled device” 
(QCCD). By changing the voltages on the 
ion traps a few ions can be confined in the 
trap or it is possible to shuttle ions from 
one trap to the next. It is possible to manip- 
ulate ions in any given trap, whilst moving 
them from one trap to the next enables 
communications. In this way it is possible 
to provide both memory and logical func- 
tions required in a computer. 

Trapped ions storing quantum informa- 
tion are held in the memory region. To per- 
form a logical function the relevant ions 
are moved into an interaction region. This 
is achieved by applying the correct volt- 
ages to the appropriate electrodes. 

It is within the interaction region that 
the logical processes are carried out. 

Here the ions are held close together to 
allow coupling. Laser light is then 
focussed on the region to drive the gates 
and once the action is complete the ions 
are moved ready to prepare for the next 

A number of structures have been fabri- 
cated for the QCCD. This is relatively easy 
using current methods. Ion traps have been 
made by machining slits in alumina wafers 
using lasers and then evaporating 
_gold onto alumina to act as the 
electrodes. Although these traps 
are experimental, they have virtu- 
ally the same dimensions that 

_ would be required for the QCCD 
computer. As an alternative tech- 
nique other structures are being 
fabricated from heavily doped 
silicon, using micro-fabrication 

The first ion traps have now been 
interconnected in what is a major 
step forwards in creating the com- 
puter. The traps used were very 
similar to those used when demon- 
Strating the functionality of the 
individual ion traps and their sepa- 
ration is 1-2mm. Using the struc- 
ture, quantum data bits or qubits 
have been successfully transferred 
with transport times as short as 50 

microseconds being observed. 

For successful operation the system has 
to be cooled. It is also found that the ions 
need to be cooled after they have been 
transported between the two traps. This is 
achieved by using what is known as sym- 
pathetic cooling where different types of 
ions to those that are transported are used. 
By confining both types of ion to the inter- 
action region enables the cooling ions to 
act as a heat sink. 

This work is claimed to be the first pre- 
sentation of a realistic architecture for quan- 
tum computation that is scalable to large 
numbers of qubits. Although many other 
organisations are working in similar fields, 
this proposal is built upon work that has 
already been tested experimentally, and it 
now appears that there is a straightforward 
path to increasing the scale of the individual 
items to build a complete computer. 

Whilst the basic building blocks have 
been tested, there is still a major amount of 
work to be undertaken before these comput- 

“ers may be realised on a workable scale. 

This means that it will be many years before 
this new technology becomes established as 
a serious contender to the semiconductor 
based machines we currently use. 

Everyday Practical Electronics, September 2002 

i Pike’ 
Experiments ideas for DrDAQ 

W you ome interested in performing and veiting up ane of these expeeknants, phaee get i touch, follow Yew is fer mare internation.) : 

Y Very low cost 
Y Built in sensors for light, sound (level and f 
waveforms) and temperature 

v Use DrDAQ to capture fast signals (eg 


sound waveforms) 

Outputs for control experiments 
>, inf Pie oeae | : Supplied with both PicoScope : 
— i a (oscilloscope) and PicoLog (data logging) Fy = 
: | if Po software 1 

OV23 45676910 } 

The DrDAQ is a low cost data logger from Pico 
Technology. It is supplied ready to use with all 
cables, software and example science 

DrDAQ represents a breakthrough in data 
logging. Simply plug DrDAQ into any Windows + 
PC, run the supplied software and you areready [| |.See ss, @) Sau . 
to collect and display data. DrDAQ draws its | SD ——  * 
power from the parallel port, so no batteries or ae hace oo a 
power supplies are required. 

As well as the built in sensors, DrDAQ has two 
sockets for external sensors. When a sensor is 
plugged in, the software detects it and 
automatically scales readings. For example, if a 
temperature sensor is plugged in, readings are 
displayed in °C . Details are provided to allow 
users to develop their own sensors. 

To order the DrDAQ please choose one of the following options: 
i) Visit our web site and place an order over the Internet, 
ii) Place an order over the phone by ringing the number below,or, 
iii) Fill out the order form and either fax it, or post it back to Pico Technology. 

DrDAQ Order Form: 
Package Total 

DrDAQ + Software £69.32 
DrDAQ + 2 Temp £92.85 

DrDAQ + 2 Temp, pH £175.08 
Electrode, Hunidity + 

Reed Switch Sensors 

Delivery £4.11 £4.14 

Grand Total | ¢ 



Post code 


Visa / Mastercard / Switch / Amex 

Start Date & or Issue No. 

Pico Technology Ltd, The Mill House, Cambridge Street, St Neots, Cambridgeshire. PE19 1QB (7 : 
Tel: 01480 396395, Fax: 01480 396296, E-mail:, Web: 

Credit Card 

Card Number 

Expiry Date 
Cheque with order 

—. No PC Required 

PEE PREGR ERROR PERE Comes ht Brinn ing Bertie 





ee eee 




Electronics and Microcontrollers 
For Absolute Beginners 

Now with our new beginners system you can learn about microcontrollers without 
needing to own a PC. 26 fascinating experiments teach the fundamentals of 
electronics. In the first 6 experiments we learn how to use resistors, capacitors, diodes, 
transistors and MOSFETs. Then we work through 20 experiments using a PIC 
microcontroller with progressively more complex circuits. The test microcontroller 
needs to be programmed with 21 different routines and all of these are contained 



Unmade System £55.00 

The unmade system (order code P602) is supplied as a 
kit. Before you can begin the experiments you will need 
to assemble and solder the programmer module and 
thermistor lead assembly. To do this you will need good 
soldering and PCB assembly skills (or know someone 
who has). Detailed wiring instructions and circuit 
diagram are included in the book. The unmade system 
also requires the links to be cut to size and stripped. 

Made up System £79.50 

The made up system (order code P6071) is supplied with 
the programmer module assembled and tested, the 
thermistor lead assembled and water proofed, and with 
the links cut to size and stripped. The entire book can be 
worked through without needing a soldering iron. 

Professional Users 

Our low cost programmer uses the PICs in their low 
voltage programming mode which considerably 
simplifies the circuit. But this does mean that one less 
input/output line is available from the microcontroller. 
The Brunning Software universal mid range PIC 
programmer module does not have this limitation. 

If you intend to delve deeply into PIC programming by 
all means begin with our low cost system to get the 
easiest start but we then recommend that you purchase 
our P401 ‘PIC Training and Development System’ which 
includes our universal mid range PIC programmer 

within the microcontroller which is at the heart of the programmer module. The system 

requires no external data so a PC is not required. 

Low cost PIC programmer module 
+ Book Electronics & Microcontrollers for Beginners 
+ Components for 26 experiments 
+ PIC16F627 test PIC 

Tools required 

To build the experimental circuits on the plugboard you 
will need small side cutters, small long nosed pliers and 
a digital multimeter. If you assemble the PCB you will 
also need a suitable soldering iron, wire strippers and a 
small amount of resin glue to waterproof the themistor 

Total price with programmer module supplied unmade (P602) ........ £55.00 connections. 
Total price with programmer module supplied made up (P601) ....... £79.50 ‘ ; 
UK Postage and insurance ..........0. cece cece ee eeeeeeee sees £ 5.00 Ordering Information 

(Europe postage & Insurance 

Electronics & Microcontrollers for Beginners 

This book introduces complete beginners to the world of modern electronics 
using the most natural way of learning. We start by learning about resistors, 
capacitors, diodes, light emitting diodes, transistors and MOSFETs in an 
easy practical way. We then wire the simplest possible microcontroller circuit 
which just switches an LED on and off. We single step through the 
programme to see exactly how the microcontroller uses its output port to 
control the LED. We add a push button to the circuit and experiment with a 
time delay programme. We add two more LEDs and experiment with 
simulated traffic lights control. We use the microcontroller to generate sound. 
First a simple tone then more complex sound patterns. 

The next task is to create a freezer thaw warning device with two different 
failure tones. We start by studying how a microcontroller can be used to 
monitor temperature using its internal comparator. Five experiments lead us 
to a comprehensive system which monitors two temperatures —5 and —14 
degrees C, and uses the microcontroller’s sleep mode to save power. 

Finally we work thought the design cycle to create a realistic dice machine 
which uses 7 LEDs in place of the dots. For this mini project we create a 

_ Circuit which enables the microcontroller to turn itself off after displaying the 
result for 30 seconds. 

Almost no theory is given yet you will learn an amazing amount of 
professional information. Just as a young child learns to speak correctly 
without being given formal grammar lessons. 

Wiring, Writing and Stepping 

Each experiment requires the reader to build and test a simple circuit on the 
plugboard using the supplied components. Building the circuit is a very 
important part of this teaching system. For circuits which use the PIC16F627 
microcontroller the test programme is written into it directly from data that is 
stored in the microcontroller on the programmer module. The test system 
allows the less complicated test programmes to be single stepped so that the 
operation of each stage can be studied. The instruction that is about to be 
processed is displayed on the liquid crystal display. 

Telephone with Visa, Mastercard or Switch, or send 
cheque/PO for immediate despatch. The prices include 
VAT if applicable. Postage as shown must be added to 
all orders. 

Web site:- 


eee ee 


cee ee 

Up Grading © 

The low cost programmer printed circuit board has provision for 
a connector to be added which allows it to be driven by a PC. We 
have several projects in their planning stages which expand this 
starter system. The bottom photograph shows a working 
upgraded system. More information will be available when the 
new projects are nearing completion. 

Mail order address: 

Brunning Software 138 The Street, Little Clacton, Clacton-on-sea, 


Essex, CO16 OLS. Tel 01255 862308 

Everyday Practical Electronics, September 2002 

Learn About Microcontrollers 

PIC Training g & Development § System 

The best place to start learning about microcontrollers is the PIC16F84. This is 
easy to understand and very popular with construction projects. Then continue on 
using the more sophisticated PIC16F877 family. 

The heart of our system is a real book which lies open on your desk while you 
use your computer to type in the programme and control the hardware. Start with 
four very simple programmes. Run the simulator to see how they work. Test them 

with real hardware. Follow on with a little theory..... 

Our complete PIC training and development system consists of our universal 
mid range PIC programmer, a 306 page book covering the PIC16F84, a 262 page 
book introducing the PIC16F877 family, and a suite of programmes to run on a 
PC. The module is an advanced design using a 28 pin PIC16F872 to handle the 
timing, programming and voltage switching requirements. The module has two 
ZIF sockets and an 8 pin socket which between them allow most mid range 8, 18, 
28 and 40 pin PICs to be programmed. The plugboard is wired with a 5 volt supply. 
The software is an integrated system comprising a text editor, assembler 
disassembler, simulator and programming software. The programming is 
performed at normal 5 volts and then verified with plus and minus 10% applied to 
ensure that the device is programmed with a good margin and not poised on the 
edge of failure. Requires two PP3 batteries which are not supplied. 

Universal mid range PIC programmer module 

+ Book Experimenting with PIC Microcontrollers 

+ Book Experimenting with the PIC16F877 (2nd edition) 

+ Universal mid range PIC software suite 
a + PIC16F84 and PIC16F872 test PICs... . . £157.41 
UK Postage and insurance............... . 100 
(Europe postage & Insurance. . £13.00. Rest of world. . £24.00) 

Experimenting with PIC Microcontrollers 

This book introduces the PIC16F84 and PIC16C711, and is the easy way 
to get started for anyone who is new to PIC programming. We begin with 
four simple experiments, the first of which is explained over ten and a half 
pages assuming no starting knowledge except the ability to operate a 
PC. Then having gained some practical experience we study the basic 
principles of PIC programming, learn about the 8 bit timer, how to drive 
the liquid crystal display, create a real time clock, experiment with the 
watchdog timer, sleep mode, beeps and music, including a rendition of 
Beethoven’s Fur Elise. Finally there are two projects to work through, 
using the PIC16F84 to create a sinewave generator and investigating the 
power taken by domestic appliances. In the space of 24 experiments, two 
projects and 56 exercises the book works through from absolute 
beginner to experienced engineer level. 

Ordering Information 

Telephone with Visa, Mastercard or Switch, or send cheque/PO for 
immediate despatch. All prices include VAT if applicable. Postage must be 
added to all orders. UK postage £2.50 per book, £1.00 per kit, maximum 
£7.50. Europe postage £3.50 per book, £1.50 per kit. Rest of World £6.50 per 
book, 2.50 per kit. 

Web site:- 

Mail order address: 

Brunning Software 138 The Street, Little Clacton, Clacton-on-sea, 

NEW 32 bit PC Assembler 

Experimenting with PC Computers with its kit is the 
easiest way ever to learn assembly language 
understand the English language and you can operate 
a PC computer then you have all the necessary 
background knowledge. Flashing LEDs, digital to 
analogue converters, simple oscilloscope, charging 
curves, temperature graphs and audio digitising. 

Kit now supplied with our 32 bit assembler with 84 page 
supplement detailing the new features and including 
7 experiments PC to PIC communication. Flashing 
LEDs, writing to LCD and two way data using 3 wires 
from PC’s parallel port to PIC16F84. 

Book Experimenting with PCs ............... £21.50 
Kit 1a ‘made up’ with software .............. £52.00 

Kit 1u ‘unmade’ with software ............... £45.00 

C & C++ for the PC 

Experimenting with C & C++ Programmes teaches us to 
programme by using C to drive the simple hardware 
circuits built using the materials supplied in the kit. The 
circuits build up to a storage oscilloscope using 
relatively simple C techniques to construct a 
programme that is by no means simple. When 

approached in this way C is only marginally more 

difficult than BASIC and infinitely more powerful. 
C programmers are always in demand. Ideal for 
absolute beginners and experienced programmers. 

Book Experimenting with C & C++ ........ £24.99 

Kit CP2a ‘made up’ with software ......... £32.51 

Kit CP2u ‘unmade’ with software .......... £26.51 

Kit CP2t ‘top up’ with software .............. £12.99 
The Kits 

The assembler and C & C++ kits contain the prototyping 
board, lead assemblies,components and programming 
software to do all the experiments. The ‘made up’ kits 
are supplied ready to start. The ‘top up’ kit is for readers 
who have already purchased kit 1a or 1u. The kits do 
not include the book. 

Hardware required 

All systems: in this advertisement assume you have 
a PC (386 or better) and a printer lead. The experiments 
require no soldering. 

Experimenting with the PIC16F877 

The second PIC book starts with the simplest of experiments to 
give us a basic understanding of the PIC16F877 family. Then we 
look at the 16 bit timer, efficient storage and display of text 
messages, simple frequency counter, use a keypad for numbers, 
letters and security codes, and examine the 10 bit A/D converter. 
The 2nd edition has two new chapters. The PIC16F627 is 
_ introduced as a low cost PIC16F84. We use the PIC16F627 as 
a step up switching regulator, and to control the speed of a DC 
motor with maximum torque still available. Then we study how to 
use a PIC to switch mains power using an optoisolated triac 
driving a high current triac. 

Essex, CO16 9LS. Tel 01255 862308 

| Everyday Practical Electronics, September 2002 

If you have enough intelligence to - 

Constructional Project 



“View” the meaning of Morse-coded tones on the air-waves, 
and enhance your skills at keying your own coded messages. 

ORSE is not dead! With modern 

communications systems abound-~ 

ing, it may seem so to the uniniti- 
ated, but in fact it is “alive and keying”. 

Whilst a cursory scan through the wave- 
bands on a modern “normal” domestic 
radio receiver may reveal little in the way 
of Morse code transmission, this commu- 
nications technique is still very much in 
use. Tuning in via a “communications 
receiver” or an older domestic receiver on 
the short wave (SW) bands will reveal 
Morse activity. 

Furthermore, if you have internet access 
and do a search through 
on such words as “Morse”, “Morse code” 
and “Morse transmission’, you will find 
literally thousands of sites devoted to the 
subject and its continuation in the modern 
world. It is, after all, an historically well- 
proven communications system, depend- 
ing purely on switching electrical, audio or 
visual signals on and off at regular 

Several printed publications which 
encourage the continued use of Morse as 
an “art form” also exist, of which Morsum 
Magnificat is one such in the UK. 



Although the author once could claim 
that he knew Morse code, having been 
taught it (and qualified!) in the Combined 
Cadet Force (CCF) at school, he too had let 
his knowledge decline and become one of 
the “uninitiated”. Until, that is, Editor 
Mike showed him an American radio pub- 
lication, Worldradio, in which there was an 
advert for a small handheld Morse Code 
Reader, undoubtedly microcontrolled. 

“Can you design one?” asked Mike. “Of 
course’, replied the author, keen to sustain 
the myth that he can do anything with PIC 


In fact, he has designed several Morse 
decoders before. The last one being pub- 
lished in Everyday Electronics in Jan ’87 
(long before the merger with Practical 
Electronics to become EPE). 

At that time PICs were probably not 
even a twinkle in the eye of any semicon- 
ductor manufacturer. They were certainly 
not reality. Consequently, the EE design 
was based on a hardware mark-space ratio 
detector which fed separate Morse dots, 
dashes and spaces via individual data lines 

to a pre-PC computer (Commodore PET 
32K). This compiled the incoming logic 
into a binary format, matched it against a 
lookup table and displayed the results on 

The design presented here is physically 
simpler, although the software is consider- 
ably more complex (that’s not your prob- 
lem, though, it was merely the author’s! 
But where’s the fun in designing if it’s not 
a challenge?). 

Details on obtaining the free software, 

and pre-programmed PICs are given at the 



There are three main aspects to this new 
design. It comprises: 

@ A handheld unit that can receive 
Morse code, via audio input (internal 
microphone) or direct signal connec- 
tion, and translate it for display on an 
in-built liquid crystal (1c.d.) alphanu- 
meric screen. The received Morse sig- 
nals are also available as pulses 
(OV/5V logic) for external use via a 
separate connection. Signals re-modu- 
lated at approximately 1kHz can be 
output to high-impedance headphones. 
With a suitably connected Morse key, 
signals can be input manually. 

@ Using a PC computer, Windows-based 
software can input the signal being 
repeated from the handheld unit, con- 
vert and display the code on the PC 
monitor, and store the translation to 
disk for future examination as a text 

@ The PC software can additionally be 
used to output Morse code to the hand- 
held unit, for display on its screen, or 
monitoring as an audio signal. There are 
several modes of code output from the 
PC: translation of a text file to Morse; 
direct keying of alphanumeric charac- 
ters for immediate translation to Morse; 
use of the keyboard as a Morse key with 
the duration of keypresses simulating 
Morse dots and dashes. 

Everyday Practical Electronics, September 2002 

im, EPE Morse Code Facility ¥ 

e hear about advances in electronics all the 
e- smaller circuits, faster chips, new devices 
and technologies. But there's another revolution 
pening. one that in afew years may change 


BD nd Cp wh mad wk OF} anh 

Typical example of the main PC screen for the EPE Morse Code Reader. 

Several other feauates are also included 

in the PC software, as will be described 


The handheld unit can be used on its - 

own. It is not necessary to use it with a 
computer. | 

Various aspects of the PC software can 

be used on their own, too, without the need 

for the handheld unit. In principle, Morse — 

code signals at normal logic levels (OV to 
5V pulses) can be directly input to the 
computer from other sources. 

The system can be used as a learning aid 
by those who wish to expand their under- 
standing of Morse. It will also satisfy the 
curiosity of those who just want to “eaves- 
drop” on what radio operators are saying 
to each other. 


International Morse code uses the dot- 
dash combinations listed in Table 1. 
Conventionally, a dot is known as “DIT”, 
and a dash as “DAH”’. 

Whilst the rate of code transmission is. 

up to the Morse operator, the relative dura- 
tion of the DITs, DAHs and associated 
spaces has been established by inter- 
national agreement: 

@ The DIT is the basic unit of length 

@ The DAH is equal in length to three 

@ The space between the DITs and DAHs | 

within a character (letter) is equal to 
one DIT 

@ The space between characters in a word 
is equal to three DITs 

@ The space between words is equal to 
seven DITs 

These are the basic requirements that 
any human operator or translation software 
must observe. 

The sending of Morse signals can take 
many forms, ranging from audio and radio 
transmission, modulation of light (e.g. 
Aldis lamps and torches), varying electri- 
cal pulse levels (e.g. sending to a comput- 
er), to bashing the water pipe if the sender 
is incarcerated at “Her Majesty’s 

In audio and radio transmission, the tech- 
nique is to turn the modulation of a carrier 
frequency (CW — continuous wave) on and 

off at the required rate. In audio work, the 
received signal is already within the audio 
range of the listener. Radio signals must, of 
course, be demodulated to become an equiv- 
alently pulsed audio signal. 

There are no set rules regarding the 
audio frequency of Morse signals, but they 
must, naturally, lie in the range most like- 
ly to be heard clearly, at about 1kHz, for 

Automatic decoding equipment, there- 
fore, must be able to accept Morse signals 
as a pulse-modulated frequency. It must 
also be able to recognise unmodulated 
pulse levels originating from a voltage 
simply being switched on and off. 

The equipment must be capable of dif- 
ferentiating DITs from DAHs, and letter 

spaces from word spaces, irrespective of 

the rate at which the Morse signals are 
being received. Ideally, it should detect if 
the transmission rate changes and then 
readjust its DIT-DAH criteria. 

The author’s last Morse decoder had to 
be manually tuned so that the software 

correctly recognised DIT-DAH ratios. The 
unit described now makes its own adjust- 
ment, typically within about eight to 16 

’ keypresses (DITs and DAHs) being 


Thus, all you need to do is place the unit 
near the loudspeaker of a radio receiver, or 
directly plug it into the coded signal 
source, and observe the unit displaying the 
received code as an intelligible text 

The term “intelligible” is used loosely, of 
course. The unit won’t translate from 
Swahili into English, for instance! It will 
simply show the letters being received. The 
advert mentioned earlier did actually state 
that its unit “instantly displays CW in 
English!” — a very clever device indeed if it 
really does that for the quoted $79.95 US! 


If you examine Morse codes as though 
DITs are logic 0 and DAHs are logic 1, a 
binary coded pattern will be seen. 
Converting from binary to decimal reveals a 
snag, however. There are some Morse codes 

that have one or more “leading” DITs, 1.e. 

leading zeros. For example, take the letters. 
E, I, S and H, which are Morse coded as 
DIT-DIT (the phrase Elephants In Straw 
Hats Ten Miles Off was that taught to the 
author to remember these four and their 
three DAH counterparts T, M, O — DAH, 

With each DIT as logic 0, the binary 
value of each of the first four letters con- 
verts to zero decimal. Not a helpful fact if 
regarding Morse codes as being true bina- 
ry symbols. 

The answer is to also take note of the 
number of keypresses (DITs or DAHs - 
call them binary bits) in a coded letter. 
Now each code can be allocated two deci- 
mal numbers, its length as well as its bina-_ 
ry value. Separate lookup tables can now 
be used, each dedicated to a particular 
code length, and then to the binary value. 
Table 2 illustrates the idea. 

Table 1. Morse codes and their reference formats used 
in the PC and PIC programs. 

Symbol Code “Binary” Count Number E 0 1 0 
F - 0010 4 2 
fo eee — 001101 6 13 G -— 110 3 6 
Heme 010010 6 18 H 0000 4 0 
f eae 011110 6 30 | 00 2 0 
( meme 10110 5 22 J —---— 0111 4 7 
) eee 101101 6 45 K a 101 3 5 
$e 01010 5 10 L ~ 0100 4 4 
(meee 110011 6 51 M -- 11 2 3 
- —.---— 100001 6 33 N - 10 2 2 
-—-—--— 010101 6 21 O --- 111 3 7 
/ —---- 10010 5 18 P -- 0110 4 6 
Oe ee 11111 5 31 Q —----— 1101 4 13 
1 «=== 01111 5 15 R - 010 3 2 
20 tee 00111 5 7 S 000 3 0 
3 -+»=-—= 00011 5 3 T - 1 1 1. & 
4 -+++=— 00001 5 1 U ~ 001 3 1 
5 --e). 00000 5 0 V - 0001 4 1 
6 —---. 10000 5 16 W — 011 3 3 
7 ----. 11000 5 24 X —--- 1001 A 9 
8 ----: 11100 5 28 Y Siar FON 4 11 
a 11110 5 30 Z ie 1100 4 12 
—-——--- 111000 6 56 A «===: 01110 5 13 
= —++-— 10001 5 sg A ave 0101 4 ‘ 
? —-—-- 001100 6 12 —---- 1111 4 15 
A - 01 2 1 ~ 00100 5 4 
B ~ 1000 4 8 N  -=----- 11011 5 27 
C —-- 1010 4 10 O ---- 1110 4 14 
D - 100 3 4 U —-- 0011 4 3 
Se a di 10101 5 = 1 = “starting” 
tees 01000 5 “wait” ; 
-. 00010 5 2 “understood” ee coe 
cea —- 000101 6 5 “End of work” recognised by the PIC 
beeen es 00000000 8 0 — “error” | 

Everyday Practical Electronics, September 2002 


Table 2 

4-bits 3-bits 2-bits 1-bit 

Bin Dec Char Bin Dec Char Bin Dec Char Bin Dec Char 
0000 O H 000 0 § 00 O | 0 O ECE 
0001 1 V 001 1 U 01 1 A 1 1 ¥ 
0010 2 F 0102 R 10 2 N none such 

Table 1 shows the full range of allocated 
codes and equivalent conversion values 
used in the PIC software and the PC 

It will be seen that some letters appear to 
be repeated but having different Morse 
codes, A, O and U, for example. This is 
because some languages (e.g. German) 
have letters that look similar to our 
“English” ones but have a double-dot 
above them (umlaut), e.g. A, O, U. Some 
letters also have “acute” and “tilde” signs 
as well, e.g. E and N. 

In this unit the codes for accented letters _ 

are recognised, but the translation is to the 
“standard” letter form. | 

Some Morse codes can have meanings 
that are specific phrases. For instance, DIT- 
DAH-DIT-DIT-DIT (01000) means “wait” 
and DAH-DIT-DAH-DAH-DIT (10110) 
means “starting”. This unit’s software 
ignores such expansions, although the 
optional PC interface software recognises 


It will be obvious that the software must 
have a “base-timing” value against which it 
assesses DIT, DAH and space lengths. 
Such lengths depend on the sending opera- 
tor’s keying speed, which can vary consid- 
erably between operators. A novice might 
send at, say, only five words per minute 
(WPM). An experienced operator could 
even be sending at 50 WPM (about 25 
WPM is a more typical rate). 

The software assesses the sending rate by 

looking for the shorter pulses (the DITs). | 

Initially, a temporary reference value is set to 
a high timing number, greater than the 
expected incoming pulse lengths. For a cycle 
covering the next 16 keypress pulses, each 
pulse timing length is compared with this 
reference. If it is less, the reference is set to 
the same value as the pulse. 

The comparison is repeated for all 16 key- 
presses. It is then assumed that the reference 
value is that representing a DIT. The DAH 
and space values referred to earlier are then 
set in respect to this value. Again the refer- 
ence value is set higher than the expected 
incoming pulse lengths and the cycle repeats. 

Simultaneously with the reference value 
comparisons, each incoming keypress is 
compared against the current DIT, DAH 
and space lengths, and each code sequence 
compiled as an equivalent binary value and 
in relation to its bit count. During the letter 
spaces the equivalent character is found 
from the respective lookup table and dis- 
played on screen. If a word space is found, 
a space character is also sent to the screen. 

DIT length comparison, of course, is not 
fool-proof and noise or sporadic changes of 
operator keying rate may cause temporary 
misinterpretation of incoming codes, proba- 
bly signified by a sequence of the letter T 
being seen. Usually, a recovery from such 
instances is made within 16 keypresses. 

It was also found that when feeding the 
unit with computer-generated codes, 
slippage could still occasionally occur. 


This is due to the PC 
aspects of its system 
even though it is also 
running the Morse 

One PC in particu- 
lar was excessively 
prone to this. It peri- 
odically decides that 
it wants to check all 
sorts of things on the 
hard drive and the 
floppies, thoroughly 
disrupting Visual 
Basic (and Quick- 

other . 


Samuel Finley Breese Morse was born in Charleston, 
Massachusetts in 1791. Studying to be a painter in the US and 
Europe, in 1832 he became intrigued by the telegraph, a system 
first built in 1774. At that time, telegraph machines required 26 
separate wires, one for each letter of the alphabet (presumably 
numerals had to be spelt out, and punctuation ignored). 

In 1833 a German 5-wire system was introduced, but Morse 
recognised that a 1-wire signalling system was possible, in 
which a series of long and short electrical pulses could be sent 
in a coded order relating not only to alphabet characters but to 
numerals and other symbols as well. | 

Now known as the “American” Morse Code, the original code 
additionally used embedded spaces as part of the coded char- 
acters. Thus dot-space-dot represented letter “O”. There were 
even codes that used extra-long dashes, e.g. letter “L’ and 
numeral “O”. 

As the code’s popularity spread, it evolved to suit the needs of 
international users. All embedded letter spaces were eliminated 
and the standardised use of dots and dashes became the code 
now in use, the “International” (or “Continental”) Morse Code. 
Letter “O”, for instance, has now become dash-dash-dash. 
Several web sites quote both code formats. 

Basic) timings. The 

reason cannot be found (the machine came 

to the author second-hand). 

Visual Basic does not allow internal 
“interrupts” to be stopped. They can be 
stopped if a machine code program is 
being run, as the author used to do when 
using QB with an m/c sub-routine, but he 
has not yet found a way to integrate m/c 
(8086 assembly dialect) with VB. (Advice 
from anyone who does know would be 

Using a PC as the Morse source, transla- 
tion rates in excess of 50 WPM were 
achieved with the PIC unit. 


The complete circuit diagram for the 
EPE Morse Code Reader is shown in Fig.1. 
Not much to it! Basically, Morse signals 
are input, amplified, translated by a 
PIC16F84 microcontroller and displayed 
on the l.c.d. screen. 

Microphone MIC1 is a miniature elec- 
tret type which receives its power via resis- 
tor R1 and allows the unit to be placed near 
the speaker of a radio receiver to pick up 
Morse signals without any physical con- 
nection to it. | 

Socket SK1 enables direct connection 
to, say, a radio receiver’s audio output 
socket, low level or line-level. The micro- 
phone is automatically disconnected in this 

Signals from the selected source are a.c. 
coupled to level control VR1 and fed to the 
amplification stage around ICla. The gain is 
set at about 100 by resistors R2 and R5. The 
values of capacitors C2 and C4 respectively 
give a bit of bass and treble cut to the audio 

frequency being received, helping to reduce 

(although not totally 
eliminate) false trigger- 
ing by any out-of-band 

The next stage extracts the Morse pulse 
“envelope” from the audio carrier signal. In 
the presence of pulses (DITs and DAHs), 
capacitor C6 is held charged via diode D1. 
When each pulse ceases, C6 discharges 
through preset VR2. 

For as long as the voltage on the wiper 
of VR2 is above about 0-6V, transistor TR1 
is turned on into full saturation, i.e. its col- 
lector voltage is at OV. When each pulse 
ceases, the collector voltage returns high, 
to 5V (the power rail voltage). 

Socket SK2 allows external (unmodulat- 
ed) Morse pulses to be input in place of the 
audio signal (from a Morse key or comput- 
er, for example). Their amplitude should 
swing between OV and greater than about 
0-6V. The software automatically compen- 
sates for the signal inversion by TR1. 


The output from TR1 is coupled to the 
Schmitt trigger input, RA4, of PIC micro- 
controller IC2. The software monitors the 
status of the input, from which information 
Morse pulse lengths are assessed. 

The status of pin RA4 is copied by soft- 
ware (suitably re-inverted) to pin RA3. This 
allows demodulated pulses to be sent, via 
socket SK4, to other equipment, such as a 
PC which itself can decode signals into 
characters and display them on its screen. 
While developing the software, the author 
actually coupled two PCs to the PIC, one 
transmitting to it, the other receiving from it. 

The pulsed signal from RA3 also drives 
an l.e.d., D3, via ballast resistor R13. This 
serves as an additional Morse code moni- 
tor. At lower transmission rates, the relative 
DIT and DAH lengths can be observed, 

noise on the signal. 
From [C1a, the sig- 
nal is a.c. coupled to 
the second amplifica- 
tion stage, around 
IC1b. Here the gain is 
set at around 10 by 
resistors R6 and R7. 
Resistors R3 and R4 
provide a midway 
bias level to both 
stages. : 


The power and sophistication of modern communications sys- 
tems, especially those via satellite, eventually eclipsed the need 
to use Morse code commercially and many radio stations world- 

wide have ceased Morse transmission and reception. 

On January 1st 1999, the UK’s 500kHz Coast Radio Station 
Service, for instance, ceased to maintain a distress watch and 
British Telecom MF Morse radio stations ceased all commercial 
Morse services. Other similar services also closed on the same 
day, some whose history goes back around a hundred years. 

Everyday Practical Electronics, September 2002 

IC2 RA2 

PIC16F84 A3 














Fig.1. Complete circuit diagram for the EPE Morse Code Reader. 

and even used as a visual source of Morse 

Provision has been made for received 
Morse signals to be repeated as re-modu- 
lated audio tones (at roughly 1-3kHz) via 
high impedance headphones, connected 
via socket SK3. This facility is included as 
part of the unit’s “learning” aspect, so that 
code transmissions simulated by the com- 
puter can be listened to and so test the lis- 
tener’s ability to mentally decode them. 

The tones are output from pin RA2, sent 
via level control VR3 to transistor TR2, to 
which the headphones can be connected 
via socket SK3. It is stressed that high- 
impedance headphones (e.g. at least 40 
ohms) must be used. The use of low imped- 
ance ’phones or a loudspeaker will kill the 
transistor (which has a rating of about 

Capacitor Cll smooths some of the 
harshness of the audio square wave — no 
attempt has been made to provide a “musi- 
cal” tone! 

In fact, using the software to generate 
the tone while carrying out other activities 
does not allow a precise audio frequency. 
Whilst the dominant frequency is about 
1-3kHz, other underlying tones are just 

If you would prefer to listen to “cleaner” 
tones and you have an existing audio 

oscillator that can be keyed by voltage 
level changes, it could be driven via the 
pulse output at SK4. 


Visual display of the decoded Morse sig- 
nals is via the 2-line 16-character (per line) 
alphanumeric l.c.d., X2. This is operated in 
standard 4-bit mode, with contrast setting 
performed by preset VR4. 

Switch S2 causes the l.c.d. to show 
either two lines of message, or one line 
plus WPM data on the other. | 

In 2-line mode, the message is compiled 
on the lower line, the characters being 
placed consecutively from left to right 
across 16 “cells”. On each 16th character 
the whole lower line is transferred to the 
top, the lower one cleared and message 
compilation starts again from the left. The 
message is not stored after being lost from 
the display. | 

In WPM mode, the WPM count is 
assessed every 60 seconds and output to 
the left of the upper line. The lower line 
shows the message as it progresses, with it 
being cleared after each 16 characters. 

At the right of the upper line is displayed 
a sub-count of the words received since 
the last one-minute display occurred. It is 
updated after each batch of 16 characters 
has been received. | 

Everyday Practical Electronics, September 2002 

Typical I.c.d. screen in 2-line code dis- 
play mode. 

Typical lI.c.d. screen showing WPM 
count on the top line. 


The PIC is run at 3-2768MHz, as set by 
crystal X1, and powered at +5V from reg- 
ulator IC3. The unit itself may be powered, 
via IC3, at any d.c. voltage between about 
7V and, say, 12V. Current consumption 
depends on the use of the headphones and 
their- loudness. In quiescent mode con- 
sumption is about 7mA. 

As usual with the author’s PIC designs, 
provision for programming the PIC in situ 
has been made via connector TB2, whose 
connections, and those to the l.c.d., are in his 
“standard” order. PIC Toolkit Mk2 or Mk3 
are suited to programming PICs in situ on 
board designs such as that used for this unit. 



R1 4k7 
R2, R6, R8, 
R9, R11, 
R12 10k (6 of) PALK 
R3, R4, R7 100k (3 off) page 
R5 1M 
R10 1k 
R13 47002 
All 0-25W 5% carbon film. 

VR1 10k rotary, log 
VR2, VR4 10k min. preset, round 
(2 off) . 
VR3 2k2 min. preset, round 

C1 1u radial elect. 16V 
C2, C3, C5, 

C8,C11  100n ceramic, 5mm pitch 

(5 off) 

C4 .100p ceramic, 5mm pitch 

C6, C7 22u radial elect. 16V 
(2 off) 

10p ceramic, 5mm pitch 
2 off) 



D1, D2 _1N4148 signal diode 

D3 red l.e.d. 

TR1, TR2 BC549 npn general 
purpose small-signal 

IC1 ~ LM358 dual op.amp 

IC2 PIC16F84-4 
see text | 

IC3 78L05 100mA +5V 
voltage regulator 

MIC1 min. electret microphone 
min. s.p.d.t. (or s.p.s.t.) 
toggle switch (2 off) 
SK1 to SK4 3.5mm plastic jack socket 
(4 off) 
X1 3-2768MHz crystal 
X2 2-line, 16-character (per 
line) alphanumeric 
l.c.d. module 

$1, S2 

Printed circuit board, available from 
the EPE PCB Service, code 368; plastic 
case, 150mm x 80mm x 50mm; 8-pin 
d.i.l. socket; 18-pin d.i.l. socket; panel- 
mounting lI.e.d. clip; knob for VR1; PP3 
battery and clip; pin header strips and 
sockets for TB1 and TB2 (see text); p.c.b. 
mounting supports (4 off); connecting 

wire; solder, etc. 

excluding battery 

VAY eo) eo} ge) Om OreX-) | 
CTU [oF Talo Ol aT 1% 


Printed circuit board layout details for 
the EPE Morse Code Reader are shown in 
Fig.2, This board is available from the EPE 
PCB Service, code 368. 

Use sockets for IC1 and IC2. Assemble 
in order of component size, preferably link 
wires first (noting that one lies under the 
socket for IC2). 

Pin header strips were used in the proto- 
type for connections to the TB1 and TB2 
pins. Alternatively, 1mm terminal pins 
could be used. 



RB6 RB7 

3-7IN (94-0mm) 



1-9IN (48-3mm) 


Fig.2. Component and full-size master track pattern layouts ve the EPE Morse 

Code Reader. 

13 @ D6 
11@ D4 

Fig.3. The two “standard” I.c.d. module 
pinout arrangements. 

Before inserting IC1, IC2 or the l.c.d., 
check the correctness of your assembly and 
that +5V is present where indicated in the 
circuit diagram of Fig.1. 

~The unit was mounted in a plastic case, 
having cut a viewing slot to suit the l.c.d. 
screen,.and holes drilled for switches, con- 
nectors, or direct external input/output 
wiring, etc. 

A hole should also be drilled for the 
lLe.d. D3 (although this was not done with 
the prototype). 

Sockets SK1 to SK4 should be plastic 
types (note that SK3 has its “common” ter- 
minal connected to the principal power line). 

Typical pinout details for the l.c.d. mod- 
ule are shown in Fig. 3. : 



For learning purposes, the use of the PC- 
based Windows software for this design is 
ideal. Written in Visual Basic 6 (VB6) the 
software is completely standalone and does 
not require VB6 to be resident on your PC 
(but see later). 

For output mode, the PC uses parallel 
port pin DO, and for input it uses pin ACK 
(see Fig.4). 

Five Morse code output modes are avail- 
able from the PC software: 

@ send text file in Morse 

@ send “Paris” as test word (reason given 

@ send all characters for which a Morse 
code is known, either in alphanumeric 
or “binary” order 

Everyday Practical Electronics, September 2002 

@ Send characters directly keyed-in via 

@ Send Morse pulses in respect of duration 
of any keypress 

The word Paris is that generally used to 
determine the words per minute rate (WPM) 
at which Morse code is transmitted. It sup- 
posedly represents the average DIT-DAH- 
letterspace-wordspace ratio encountered in a 
typical message transmission. 

Clicking on the Send Paris button caus- 
es the software to repeatedly output this 
single word followed by a wordspace. 
Clicking on Stop TX/RX ends this mode 
(as it does for any transmission or recep- 
tion mode). During any transmission, the 
message being processed is displayed in 
the left hand panel. 


A slider below the message panel sets 
the WPM rate at which any transmission is 
sent. The actual rate for a given setting is 
likely to vary between different PCs (the 
scale values shown below the slider are 
those used by the author). A facility has 
been provided to “tune” the scales to the 
rate actually produced by your PC for a 
given slider setting. Transmission of 
“Paris” is the mode to use for this. 


Fig.4. 25-way male D-type connector. 


or ee ee or Me oF om 

PE Morse C 
ponte mi 



displaying timed counts in the box below 
the scales. The assessment is in relation to 
the number of DITs in the message multi- 
plied by 1-2 (a factor quoted to the author 
by a Morse expert). 


While browsing the web for Morse code 
info, it became apparent that learners of 
Morse can become tired of repeatedly lis- 
tening to pre-recorded Morse test message 
tapes. The option to send any message you 
like has thus been included here. 

It is intended that any Morse output from 
the PC is routed to the EPE Morse Code 
Reader unit. How it is then used is up to you. 
The most obvious use is to output an unfa- 
miliar text file, listen to the Morse tones gen- 
erated by the unit, and practice your decod- 
ing skills. The software is not linked to any 
audio interface installed on the PC. 

To send a text file, click on Text File 
Directory to enter a typical Windows-style 
folder, path and file selector, through 
which any listed text file can be loaded for 
output as Morse code. Double-click on the 
file name chosen to select it and return to 
the main screen. The selected file name is 
confirmed at the bottom left of the screen. 
Only files having a .TXT extension can be 

Then click on Send Test File to start 
transmission. Click Stop TX/RX to end it. 

Above: Example of the main screen showing the Paris transmitted test message in 
the left hand text box and codes in “binary” order in the right hand panel. 

Below: Typical example of the directory screen 

Clicking on the button Edit TX Scales 
allows you to change scale legends via the 
keyboard. A Save TX Scales button is dis- 
played while in this 
facility. Having 
changed the scales to 
your satisfaction, 
click this button to 
save the information 
to disk. It will be 
recalled next time you 
run the program. 

Irrespective of the 
slider setting, the 
software makes a 
separate assessment 
of the WPM sate 
actually occurring, 

Everyday Practical Electronics, September 2002 

The chosen file can also be viewed via the 
PC’s Notepad text editor by clicking on 
View Text File. 

The Directory screen is a cut down ver- 
sion of that used in the author’s Toolkit 
TK3 PIC programming software (Oct-Nov 
01). More details about using this option 
can be viewed via the Directory screen’s 
NOTES button (there are several sub- 
options discussed). 

Clicking Send All Codes outputs 

standard Morse codes in alphanumeric or 

binary order, depending on whether the 
Codes-Alpha or Codes-Binary button has 
been clicked (confirmed by it showing blue 
instead of green). The full code set for each 
selection is displayed in the right hand sub- 
window (it can be scrolled up or down for 

The codes displayed can be hidden 
should you wish to by clicking Hide 


Clicking either Send Text via Keyboard 
or Send Morse via Keyboard, appropriate- 
ly activates one of those two modes. In the 

keyed Text-mode you should not allow 
_ your keying rate to exceed the WPM rate 
set by the slider (although the normal 

Windows keyboard buffer will take up the — 

“slack” for a while). 

Use almost any key you like to send 
Morse highs and lows as DITs and DAHs 
(but Num Lock will probably need to be 
On in order to use the right hand numeric 
keypad). The rate of keying is up to you 
and is not affected by the WPM slider. 

The author is much too way out of 
Morse keying practice (by many decades!) 
to know how successful the keyboard DIT- 
DAHing might be, but it seemed an option 
that was worth adding in case it might be of 
any use. 


When first loaded, the PC software 
detects whether or not the program has 
been run before on the machine in use. If it 
has not, a set of internal routines are initi- 
ated which, among other things (relating to 
clearing any personal directory and other 
records accidentally left in by the author!), 
establishes a nominal base value used dur- 
ing code transmission. 

Such values will vary from PC to PC. 
The value can also be set via the Set 
Timing button should you wish, the result- 
ing value being displayed below. this but- 
ton. Note that it is simply a “looping” value 
used by the software and not a timing value 
in terms of specific units of time. 

The assessment takes a couple of sec- 
onds, and it is normal for the value to dif- 
fer slightly each time the assessment is 
made (due to the PC’s own interrupts as 
mentioned earlier). 


The software does not assess for itself 
the printer port register that your computer 
has been set to use. This is typically regis- 
ter 378h (hex), but could be 278h or 3BCh. 
At the bottom right of the screen is a PORT 
box with radio buttons which select the 
register to be used. 

To check which one is correct, first leave 
the setting at the default of 378h and start 


sending “Paris” to the Morse Reader unit 
and observe its l.c.d. screen. If nothing 
appears on the l.c.d. within a few seconds, 
click on 278h. Again wait a while. If still 
nothing appears, try 3BCh. 

If there is still no success, re-check the 
unit and its connections to the PC. 

The selected port register value is auto- 
matically stored to disk for recall next time 
the program is run. 


It is believed that the PC software is 
totally relocatable in terms of which drive 
or folder it is run from. Normally, it is like- 
ly that you will wish to run it from your C- 
drive. Alternative drive letters (including a 
partition) may be selected via the Drive 

option at the bottom right of the screen. 

This selection is also stored to disk for 
future recall. | 

Do not use a floppy or CD-drive from 
which to run the software. It is preferable 
to remain with the standard C-drive if 


The PC software has been subjected to’ 

extensive “error-mode” checking and 
includes various error-trapping routines. If 
something unexpected occurs in an error- 
trapped routine, you will be advised so via 
a separate Error Message screen. 

However, if something occurs for which 
the author has not provided an answer or 
interception, let him know via the Editorial 
office (not via the Chat Zone as he does not 
necessarily access this on a regular basis 
and your message might be missed). 


Finally, to exit the PC Morse software 
click on the Quit Morse Program button, 
which will fully close it. If you use the top- 

right Windows X button, the program may 

only become “hidden”, remaining active in 
the Desktop screen’s lower toolbar. 

It is worth exploring your Morse screen 
with the mouse cursor. There are various 
notes that appear when it hovers briefly 
over buttons and labels. 


Should you wish to add a new Morse 
code item to those known to the PC soft- 
ware (author!), you can do so by accessing 
file MorseCode.txt held in the main 
Morse folder. Double-click on the file to 

open it through Notepad. It can now be’ 

amended, and resaved as the same name 
and file type. 

Do not edit the file via a wordprocessing 
program since this might add format codes 
which would affect the correct use of the 

file by the Morse software. 


Software for the PIC unit and PC inter- 
face is available on 3-5-inch disk from the 
Editorial office (a small handling charge 
applies) or downloaded free from our ftp 
site. The latter is accessible via the top of 
the title page of the main EPE web site at Click on 
“FTP Site (downloads)’, then in turn on 
PUB and PICS, in which page the files are 
in the folder named MORSE. 

More details of both options are given on 
this month’s Shoptalk page, plus information 
on obtaining pre-programmed PICs. 

The PIC program (ASM) was written in 
TASM, although the run-time assembly is 
supplied both as a TASM OBJ file and an 
MPASM HEX file (the latter has configu- 
ration values embedded in it). Users of the 
TASM OBJ file should configure their PIC 
for crystal XT, WDT off, POR on. 

Regarding the PC interface, if you have 
Visual Basic 6 already installed on your 
machine you only need to use files 
Morse.exe, INPOUT.DLL and Morse 
Code.txt. Copy them into a new folder 
named MORSE (or any other of your 

If you do not have VB6, you need three 
other files, comdlg32.ocx, Mscomctl.ocx 
and Msvbvm60.dll, held on our 3-5-inch 
disk named Interface Disk 1, and in the 
Interface folder on the ftp site (they are 
also included with the Toolkit TK3 soft- 
ware). These files must be copied into the 
same folder as the other three files. 


There are too many web sites devoted to 
Morse code for them to be listed here. 
However, do as the author did (and men- 
tioned earlier), search via 
com (an excellent search engine). 

Those who wish to know more about 
becoming an amateur radio operator in the 
UK should contact the Radio Society of 
Great Britain (RSGB). They will also 
advise details of their Morse test transmis- 
sions, courses and exam requirements. 
RSGB, Lambda House, Cranborne Road, 
Potters Bar, Herts EN6 3JE. Web: 

Books by our New Technology author, 
Ian Poole, also provide information about 
amateur radio. Browse 

Morsum Magnificat is a bi-monthly 
magazine that has been around since 1983 
and “is for all Morse enthusiasts, amateur 
or professional, active or retired. It brings 
together material which would otherwise 
be lost to posterity, providing an invaluable 
source of interest, reference and record 
relating to the traditions and practice of 

Information about MM can be obtained 
through Morsum Magnificat, The Poplars, 
Wistanswick, Market Drayton, Shropshire 
TF9 2BA. Tel: 01630 638306. Fax: 01630 
638051. E-mail: 
Web: (It can also be 
found at [J 

Everyday Practical Electronics, September 2002 



We can supply back issues of EPE by post, most issues from the past three years are available. An EPE index for the last five years is also available — see order form. 
Alternatively, indexes are published in the December issue for that year. Where we are unable to provide a back issue a photocopy of any one article (or one part of a 
series) can be purchased for the same price. Issues from Jan. 2002 onwards are also available to download from : 

MAY ’01 ad a0) (oly €-] (ee) a] 

PROJECTS e Camcorder Mixer @ PIC Graphics 
L.C.D. Scope @ D.C. Motor Controller @ Intruder 
Alarm Control Panel—Part 2. 

FEATURES @ The Schmitt Trigger—Part 7 e 
Interface @ Circuit Surgery @ Ingenuity Unlimited @ 
New Technology Update @ Net Work — The 
Internet Page. 

JUNE ’01 

PROJECTS @ Hosepipe Controller @ In-Circuit 
Ohmmeter @ Dummy PIR Detector @ Magfield 

FEATURES e Controlling Jodrell Bank e 
PIC1687x Extended Memory Use @ Practically 
Speaking @ Ingenuity Unlimited @ New 

Technology Update @ Circuit Surgery @ Net Work | 

— The Internet Page. 

JULY ’01 

PROJECTS e Stereo/Surround Sound Amplifier 
e@ PIC to Printer Interface @ Perpetual Projects 1— 
Solar-Powered Power Supply and Voltage 
Regulator e MSF Signal Repeater and Indicator. 

FEATURES e The World of PLCs @ Ingenuity 

Unlimited @ Circuit Surgery @ New Technology © 

Update @ Net Work — The Internet Page. 

PROJECTS e Digitimer @ Lead-Acid Battery 

Charger @ Compact Shortwave Loop Aerial @ - 

Perpetual Projects 2 — L.E.D. Flasher — Double 

FEATURES e Controlling Power Generation @- 

Ingenuity Unlimited @ Interface e Circuit Surgery 
@ New Technology Update @ Net Work. 

SEPT ’01 

PROJECTS e Water Monitor @ L.E.D. Super 
Torches @ Synchronous Clock Driver @ Perpetual 
Projects 3 — Loop Burglar Alarm — Touch-Switch 
Door-Light — Solar-Powered Rain Alarm. 

FEATURES e Controlling Flight @ Ingenuity — 

Unlimited @ Practically Speaking @ Circuit Surgery 
e@ New Technology Update @ Net Work — The 
Internet Page. 


New Teehnotegy & 
Readout » Metwork 

OCT '01 

PROJECTS e PIC Toolkit Mk3 @ Camcorder Power 
Supply @ 2-Valve SW Receiver @ Perpetual Projects 
4 — Gate Sentinel — Bird Scarer — In-Out Register. 

FEATURES e Traffic Control @ Ingenuity Unlimited 
e@ New paieen Update e@ Circuit Surgery @ 

Photostats onl 

Interface @ Net Work — The Internet Page @ Free 
2 CD-ROMs — Microchip 2001 Tech Library. 

NOV ’01 

PROJECTS e Capacitance Meter e Pitch Switch e 
Lights Needed Alert @ Teach-In 2002 Power Supply. 
FEATURES e@ Teach-In 2002 — Part 1 @ Practically 
Speaking @ Circuit Surgery @ New Technology 
Update @ Ingenuity Unlimited ¢ Net Work — The 
Internet Page @ Free 16-page Supplement — PIC 
Toolkit TK3 For Windows. 

DEC ’01 

PROJECTS e Ghost Buster e PIC Polywhatsit @ 
Twinkling Lights @ Mains Failure Alarm. 
FEATURES @ Teach-In 2002 — Part 2 @ Marconi — 
The Father of Radio e Interface @ Ingenuity 
Unlimited @ Circuit Surgery @ New Technology 
Update @ Net Work — The Internet Page @ 2001 
Annual Index. 



JAN ’02 

PROJECTS e PIC Magick Musick @ Time Delay 
Touch Switch @ Versatile Bench Power Supply @ 
Forever Flasher. 

FEATURES e Teach-In 2002 — Part 3 @ Practically 
Speaking @ Ingenuity Unlimited e New Technology 
Update @ Circuit Surgery @ Net Work — The Internet 


FEB 02 

PROJECTS e PIC Spectrum Analyser @ Guitar 
Practice Amp @ HT Power Supply @ Versatile 
Current Monitor. 
FEATURES e Teach-In 2002 — Part 4 @ Ingenuity 
Unlimited @ Russian Space Shuttle Revisited @ 
Circuit Surgery @ Interface @ New Technology 
Update @ Net Work — The Internet Page. 

PROJECTS @ MK484 Shortwave Radio @ PIC 

Virus Zapper @ RH Meter @ PIC Mini-Enigma. 

FEATURES e Teach-in 2002 — Part 5 @ Ingenuity 

Unlimited @ Programming PIC Interrupts—1 @ 

Circuit Surgery @ Practically Speaking @ New 

a Update @ Net Work — The Internet 

APR ’02 

PROJECTS e Electric Guitar Tuner @ PIC 
Controlled Intruder Alarm @ Solar Charge and Go 
@ Manual Stepper Motor Controller. 

FEATURES @ Teach-In 2002 — Part 6 e Interface 
@ Programming PIC Interrupts—2 @ Circuit Surgery 
@ Ingenuity Unlimited e New Technology Update 
@ Net Work — The Internet Page @ FREE Giant 
Op.Amp Data Chart. 


MAY ’02 

PROJECTS e PIC tog Display @ Simple Audio 

Circuits — 1 @ Freezer Alarm @ Washing Ready 


FEATURES e@ Teach-In 2002 — Part 7 @ Ingenuity 

Unlimited @ Practically Speaking @ New Technology 

oe @ Circuit Surgery @ Net Work — The Internet 

JUNE ’02 

PROJECTS e Biopic Heartbeat Monitor e 
Frequency Standard Generator @ Simple Audio 
Circuits — 2 @ World Lamp. } 

FEATURES e Teach-In 2002 — Part 8 @ Interface @ 
New Technology Update e Circuit Surgery @ 

Ingenuity Unlimited @ Net Work — The Internet 


JULY ’02 

PROJECTS e EPE StyloPIC e Infra-Red 
Autoswitch @ Simple Audio Circuits — 3 @ Rotary 
Combination Lock. ~~ 

FEATURES e Teach-In 2002 — Part 9 @ Practically 
Speaking @ Using The PIC’s PCLATH Command 
e@ Ingenuity Unlimited @ Circuit Surgery e New 
Technology Update @ Net Work—The Internet Page. 

AUG ’02 

PROJECTS e PIC World Clock @ Pickpocket Alarm 
@ Big-Ears Buggy @ Simple Audio Circuits — 4. 
FEATURES e Teach-In 2002 — Part 10 @ Using 
Square Roots with PICs @ Ingenuity Unlimited @ 
Evolutionary Electronics @ Interface @ Circuit 
Surgery @ Net Work — The Internet Page. 

BACK IssuES ONLY £3.30 each inc. UK p&p. 
Overseas prices £3.80 each surface mail, £5.25 each airmail. 

We can also supply issues from earlier years: 1998 (except Jan. to May, July, Nov., Dec.), 1999, 2000 
(except Feb., July), 2001 (except May, Oct.). Where we do not have an issue a photocopy of any one 
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th Your ervirony 


BACK ISSUES — November 1998 to June 1999 (all the projects, 
features, news, |Us etc. from all eight issues). Note: No advertise- 
ments are included. PIC PROJECT CODES - All the available 
codes for the PIC based projects published in these issues. 


BACK ISSUES — July 1999 to December 1999 (all the projects, 
features, news, |Us, etc. from all six issues). Note: No advertisements 
are included. PIC PROJECT CODES - All the available codes for the 
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BACK ISSUES -— January 2000 to June 2000 (all the projects, features, 
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BACK ISSUES -— July 2001 to December 2001 (all the projects, 
features, news, |Us etc. from all six issues). PROJECT CODES - All the 
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those for /nterface. 


BASIC SOLDERING GUIDE -— Alan Winstanley’s internationally 
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NENTS -— Introduction to the basic principles of passive components. 
HOW TO USE INTELLIGENT L.C.Ds, By Julyan Ilett — An utterly practi- 
cal guide to interfacing and programming intelligent liquid crystal display 
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COMPUTER SYSTEMS 3D GRAPHICS - A chapter from Intergraph’s 
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THE LIFE & WORKS OF KONRAD ZUSE - a brilliant pioneer in the 
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A great way to buy EPE Back Issues — our mini CD-ROMs contain 
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Constructional Project 



Clean up those old records, dust down 

that turntable and let's get burning! 

O YOU have a collection of old vinyl 

records? If so, you might wish to | 

transfer them to CDs. By doing this, 
you will preserve their value because you 
will only need to play them once. 

It may even be possible to enhance the 
sound by removing some of the back- 
ground noise and clicks which are found 
on worn recordings. If you have a CD 
player in your car or own a portable unit, 
you will also be able to play your work “on 
the move”. 


To transfer a recording to CD, you need 
a computer with a Compact Disc writer 
installed. Many new machines, of course, 
already have one of these. If yours is not so 

equipped, you will find that fitting a 

CD “burner” module is inexpensive and 

You do not even need a particularly 
modern machine. A Pentium 133MHz PC 
may suffice but a new up-to-date machine 
will be much quicker (that is, produce a 
CD at the higher speeds allowed by the 
writer). Before purchasing any hardware, it 
is important to check compatibility with 
the supplier/manufacturer. 

To record sound files on to the hard 
drive before transferring them to a CD will 
require quite a lot of spare capacity. If your 
drive is almost full, you will need to back 
up files in order to clear sufficient space. 
To record stereo tracks in 16-bit resolution 
at 44-1kHz (CD quality) you will need 
some 600MB for one hour of work and 
you could run into trouble if you do not 
have at least 800MB available. 


It is not a good idea to link the record 
deck to the computer sound card direct by 
plugging it into the microphone input. Some 
people have done this thinking, quite cor- 
rectly, that a magnetic cartridge provides a 
low-level output comparable with that of a 
dynamic microphone. Although this may 
work, the results will be very disappointing. 
This is because no equalisation has been 
applied to the signal. It will be found that the 

copy recording is.deficient in bass (low fre- | 

quencies) but have excessive treble (high 
frequency content). In other words, it will 
sound very “tinny”. More will be said about 
equalisation presently. 

A better method would be to use an 
existing hi-fi amplifier. The record deck 
would be plugged into its “Phono” input 
and a Line (high level) output obtained at 
the back (the one used for tape recording). 

This would be connected to the line input. 

on the sound card using a piece of twin- 
screened wire fitted with the appropriate 
connectors. The phono connection would 
provide the necessary equalisation. 

Unfortunately, many modern amplifiers 
make no provision for playing “old fash- 
ioned” vinyl discs. You may therefore find 
that it has no phono input. Even if you do 
have a suitable amplifier, it may need a 
long connecting lead to reach the comput- 
er Station and this could result in hum pick- 
up and degraded performance. 


. The circuit described here is a small bat- 
tery-operated stereo preamplifier which 
provides equalisation and boosts the output 


Everyday Practical Electronics, September 2002 

of a magnetic cartridge to line-level. There 
are also Scratch and Rumble filter push- 
button switches. These may be used to 
reduce the effects of surface clicks and 
low-frequency motor or turntable noise 

As well as being useful for making CDs, 
the preamplifier will be found handy by 
enthusiasts who simply wish to play their 
vinyl records using a hi-fi amplifier that 
does not have a phono input. Some readers 
may even use it for tape or Mini Disc work 
or for making MP3 files to be sent over the 

In operation, the circuit requires some 
40mA and the four AA size cells housed 
internally will provide up to fifty hours of 
service. A front panel mounted l.e.d. indi- 
cator requires some 15mA so, if the user 
can be trusted to switch the unit off after 
use, the l.e.d. may be omitted. This would 
give a significant increase in battery life. 
For extended periods of use, a larger bat- 
tery could be placed externally. 

This unit must not be powered using a 
mains-derived low-voltage supply (such 
as a plug-in adaptor). 


Returning to the topic. of equalisation, 
this must be applied if analogue recordings 
are to be reproduced with any degree of 

fidelity. To understand why this is neces- 
sary, you need to know something about 
the recording process. 

Imagine the sound has three “bands” 
comprising the low, intermediate and high 
frequency content. When the groove was 
cut in the master disc, the low frequency 
part was reduced in level (volume) while 
the high frequencies were increased. Only 
the intermediate band was left unchanged. 

Leaving the low frequencies as they 
were in the original sound would have 
required more violent movements of the 
groove cutter (that is, heavier modulation). 
This would have produced a wider groove 
and a consequent reduction in available 
playing time. Also, the playing stylus 
might have difficulty following such a 
groove and it may tend to jump out. By 
reducing the level of the low-frequency 
sound, it is possible to obtain a uniform 
groove width and a longer playing time. - 

Equalisation is the process by which the 
high and low frequency content from the 
cartridge are restored to their original state 
and, in theory, should be an exact mirror of 
that used during recording. Note that by 
restoring the high frequencies, the surface 
noise present during playback (which is 
made up chiefly of high frequencies) is 

reduced. It thus provides a simple means — 

of noise reduction. 


Unfortunately, different equalisation 

standards have existed regarding the val-_ 

ues of the cut-off frequencies defining the 
low, intermediate and high bands and also 
the degree of “cut” or “boost”. The same 
circuit will therefore not provide perfect 
results with all records. 

However, most vinyl discs produced 
since the 60s have followed the RIAA 
(Recording Industry 
Association of 
America) standard. 
In practice, an 
equaliser designed 
for this standard 
will also provide 
good results when 
applied to record- 
ings using a differ- 
ent one (American 
Standard Record 
and British Micro- 
groove format). It 
should also be suit- 
able for 78s. 

Practical equali- 
sation circuits can 
range from the sim- 
ple (which provide 
only a coarse cor- 
rection) to the very 
complex. This circuit lies somewhere near 
the middle of the range and provides good 
results without special adjustment. 

The graph shown in Fig.1 illustrates the 
ideal (theoretical) RIAA equalisation com- 
pared with that provided by this circuit. 
Note that this is for illustration only and is 
not drawn to scale. 

The section to the left-hand side labelled 
“A” provides a “roll-off’ of frequencies 
below some 10Hz. This reduces the “rum- 
ble” that is transmitted from the motor or 
turntable bearing to the cartridge through the 
turntable. This is much more pronounced 

666 | 

with a cheap unit and without such a “cut” 

would be accentuated due to the low-fre- 

quency boost made during equalisation. 
Before proceeding to construct this cir- 

cuit, check that you have a good quality 

record deck available. This must be fitted 
with a magnetic cartridge (not a ceramic 
one). If you wish to transfer 78 r.p.m. 
records, make sure your turntable will 
operate at this speed (many are designed 
for 33/45 only) also that it is fitted with the 
correct type of stylus. 


The full circuit diagram for the 
Vinyl To CD Preamplifier is shown in 
Fig.2. This is built around three identical 
dual low-noise operational amplifiers 
(op.amps) — ICla/IC1b, IC2a/IC2b and 

Equalisation of left and right channels is 
centred around IC1 and IC2 respectively, 
while IC3 is a “straight” amplifier which 
boosts both channels to line level. 

It is only necessary to describe the 
action of one channel (the left-hand one) 
since the other is the same. Note that the 
component numbering for the right-hand 

- channel is prefixed with a “one hundred”. 

Thus, R2 (left) corresponds with “R102” 
(right). Components which are common to 
both channels, the i.c.s, switches and 
input/output sockets are numbered as if 
they belonged to the left channel. 


The first section of the circuit is a non- 
inverting amplifier ICla. The signal 
obtained from the input cartridge (left- 
hand channel) at SK1 is applied to the non- 
inverting input, pin 3, via capacitor C2 (or 
Cl and C2 in parallel if Rumble switch 
Sla contacts are closed). 

Fig.1. Equalisation graph (not to scale): a) roll-off; b) fall-off 
and c) high frequency filtering. 

This, in conjunction with fixed resistor 
R3, determine the anti-rumble characteris- 
tics of the circuit (the roll-off below 10Hz 
labelled “A” in Fig. 1). Resistor R3 also 
sets the input impedance making it suit- 
able for a standard magnetic cartridge. 

Anti-rumble processing comes about 
because the impedance of capacitor C2 
rises as the frequency falls. High frequen- 
cy signals will then flow more easily 
through resistor R3 and hence through 
capacitor C3 (which has a relatively high 
value and therefore negligible impedance 
at these frequencies) to OV. 

It is, therefore, the higher-frequency sig- 
nals which develop a greater voltage at | 
ICla pin 3. In other words, the low fre- 
quencies tend to be filtered out. 

With the Rumble switch contacts 
closed, the pair of capacitors C1 and C2 
give the same effect as a single unit having 
a larger value. This decreases the overall 
impedance and the circuit rolls off at a 
lower frequency. 


The output of IC1a at pin 1 is connected 
to its inverting input (pin 2) through the 
parallel arrangement of resistor R5 and 
capacitor C4. This works in conjunction 
with resistor R4 to set the gain. 

The other end of R4 is connected to the 
mid-point of a potential divider consisting 
of equal-value resistors R1 and R2. This 
sets a d.c. voltage nominally equal to one- 
half that of the supply — that is, 3V. This 
provides a “zero” reference so that the a.c. 
input signal will rise and fall with respect 
to it. 

If the reference was a true OV (the volt- 
age of the OV supply line), the negative 
half-cycles of the wave would not be 
amplified. This is because the output volt- 
age cannot fall below OV. As it is, the out- 
put signal will swing above and below the 
3V level. 

Ignoring the effect of capacitor C4 for 
the moment, the gain of this section is 
approximately eight times. However, with 
C4 in place, the impedance of the feedback 
loop will fall as the frequency rises. This 
reduces the gain at higher frequencies and 
provides the “fall-off’ characteristic 
shown by Fig.1 section “B”. 

Section IC1b of the circuit is configured 
as a unity-gain amplifier (buffer). The sig- 
nal from [Cla output, at pin 1, passes 
through resistor R7 (or R6 connected in 
parallel with it when Scratch switch con- 
tacts $2a are closed) to IC1b’s non-invert- 
ing input at pin 5. 

High frequency signals now flow more 
easily through capacitor C5 (due to its 
reduced impedance) and hence to a further 
“false zero” derived from the potential 
divider made up of resistors R8 and R9. The 
voltage appearing at IC1b pin 5 will there- 
fore be less than with higher frequencies. 
The higher frequencies therefore tend to be 
filtered out (shown by section “C” in Fig.1). 


With Scratch switch S2a contacts 

closed, resistors R6 and R7 are placed in 

parallel and provide near-RIAA high-fre- 
quency attenuation. With the switch con- 
tacts open, resistor R7 alone provides a 
more dramatic cut-off and provides the 
“scratch reduction” effect. These values 
may be experimented with or a “tone con- 
trol” could be fitted to give a continuously 
variable effect. More will be said about 
this later. 

The output from IC1b, pin 7, is now 
equalised but still at a low level. The next 
section, centred around [C3a, is an ampli- 
fier used in inverting mode. This boosts the 
signal by a large factor making it suitable 

- to drive the line input of a sound card or 

external power amplifier. 

Capacitor C7 allows the output signal 
from IC1b pin 7 to pass with little loss 
(due to its relatively low impedance at 

Everyday Practical Electronics, September 2002 

R1, R101, 
R2, R102, 
R8, R108, 
R9, R109 2k2 (8 off) 
R3, R103, 
R4, R104 
R10, R110, 
R11, R111 47k (8 off) 

R5, R105, 
R6, R106 330k (4 off) | 
R7,R107 120k (2 off) 
R12, R112 15k (2 off) 
R13, R113  1M65 (2 off) 
R14 270Q 
All resistors 0-6W 1% metal film. 

‘' VR1, VR101 1M min. enclosed carbon 
preset, vert. (2 off). 

C1,C101 470n polyester film (2 off) 
C2,C102 330n polyester film (2 off) 
C3, C103, 
C6, C106 22u min. radial elect. 16V 
C8, C108 (6 off) 
C4,C104 10n polyester film (2 off) 
C5,C105 2n2 polyester film (2 off) 
C7,C107 ~=1p polyester film (2 off) 
C9,C109 10pF ceramic (2 off) | 
Ci0,C110 10y min. radial elect. 16V 
(2 off) 
C11 220p min. radial elect. 

D1 3mm red |.e.d. 
IC1 tolIC3 NE5532AN dual low- 
noise op.amp (3 off) 


$1 to S3 d.p.d.t. interlocking push- 
button switch — see text 
(3 off) 

B1 6V battery pack (4 x AA 
alkaline cells) 

SK1 to SK4 phono socket, single 
hole, panel mounting 
(see text) (4 off) 

Printed circuit board available from the 
EPE PCB Service, code 366; 8-pin d.i.l. 
i.c. socket (3 off); aluminium instrument 
case, size 150mm x 100mm x 75mm; 
battery holder and connector; 3mm l.e.d. 
clip; screened cable; multistrand con- 
necting wire; solder, etc. 

V Ve) o) ge) al Oves [2 rs | 
TUT [e F-Tator-m OJ 011% 

excl. batts. & case 


Everyday Practical Electronics, September 2002 

audio frequencies) through resistor R12 
and hence to IC3a inverting input at pin 2. 
Ignoring ‘capacitor C9 for the moment, 
fixed resistor R13 connected in series with 
preset potentiometer VR1 provides nega- 
tive feedback and, in conjunction with 
R12, sets the gain. 

This will be some 170 times with VR1 
set to its maximum value and 100 times at 
minimum. Preset VR1 will be adjusted at 
the end to provide a suitable output for the 
particular cartridge being used. 

The value of resistor R13 could be 
increased to provide a greater gain if this is 
shown to be necessary at the testing stage. 
By adjusting preset VR1 in conjunction 
with its opposite number in the other chan- 
nel (VR101), the circuit will also be “bal- 
anced” to provide equal outputs for both 


Returning to capacitor C9 which appears 
in IC3a feedback loop, its small value pro- 
vides an extremely high impedance at 
audio frequencies. It therefore normally 
has negligible effect. 

However, if radio-frequency signals hap- 
pen to be picked up by the circuit, the 
impedance of C9 will be low. This will 
lower the impedance of the feedback loop 
and reduce the gain at these frequencies. 
This prevents instability. 

The output signal finally passes from 
IC3a pin 1, via capacitor C10, to Line 
Output socket, SK3 (Left channel). 


Construction of the Vinyl To CD 
Preamplifier is based on a single-sided 
printed circuit board. This board is avail- 
able from the EPE PCB Service, code 366. 
The topside component layout and actual 
size underside copper foil master pattern 
are shown in Fig.3. 

Commence construction by drilling the 
three mounting holes as indicated. Solder 

the spring-loaded, pushbutton switches in © 

position. If the specified type is not 
available, use toggle or slide units and 
hard-wire these to the appropriate points 
on the p.c.b. at the end of construction. 
Next, solder in position the three i.c. 

Follow with all resistors, preset poten- 
tiometers and capacitors — taking particular 
care over the polarity of the electrolytics. 
Solder the battery connector to the +6V. 
and OV points on the p.c.b., again, taking 
care over their polarity. Adjust presets VR1 
and VRIO1 to approximately mid-track 
position to provide a medium degree of 
gain for each channel. 


Note that this circuit must be housed in 
a METAL box to provide adequate screen- 
ing against hum pick-up. 

Decide on a suitable layout for the inter- 
nal components. Measure the positions of 
the switches and l.e.d. on the p.c.b. Mark 
these on the front panel of the box at the 
half-height level and drill them through. 
Mark and drill the p.c.b. mounting holes 
also those for the battery holder and the 
input and output sockets. 

Cut plastic stand-off insulators to the 
correct length so that, when the p.c.b. is in 
position, the switch buttons will pass 
through their holes with a little clearance. 


Secure the p.c.b. and make sure the switch- 
es operate freely. 

Attach the battery holder and the input 

and output sockets. If these are of the spec- 
ified type, you will need to scrape away the 
paint on the inside surface of the box to 
allow the outer (“sleeve”) connections to 
make good metallic contact with the case. 

Attach one of the solder tags supplied 
with the sockets under the fixing nut of one 
of them. This will be used to “earth” the 
“OV” wire leading from the circuit board. 


If you are using sockets of the fully-insu- 
lated type rather than the specified pattern, 
the sleeve connection of each must be con- 
nected to the case (OV) using a separate 
solder tag. | 
Referring to Fig.4 and photographs, 
complete the internal wiring. Take care that 
left and right inputs and outputs maintain 
their identity during the wiring process 
(that is, they do not become interchanged). 
Set all switches to the “out” position, insert 
the batteries and attach the lid of the case. 

Fig.3. Printed circuit board component layout and full-size underside copper track 
master pattern for the Vinyl To CD Preamplifier. 

Everyday Practical Electronics, September 2002 



Unless the stylus on the record deck is 
known to have given very little service, 
renew it. Styli cost very little compared 
with that of your record collection. Also, a 
new stylus will give better results. If you 
are going to transfer 78s you must have the 
correct stylus fitted — do not use one made 
for 33s/45s. | 

It would be useful to have the turntable 
manual available to help make optimum 
stylus pressure and anti-skid adjustments. 
Sometimes a slightly greater pressure than 
normal will give better results. Although 
this wears the record more quickly it may 
be worthwhile since the record need only 
be played once. | 

For initial testing, connect the output of 
the preamplifier to the line input of a hi-fi 
amplifier using twin-screened cable fitted 
with the appropriate connectors. Do not 
connect it to the computer sound card at 
this stage. 

Connect the turntable to the preamplifier 
input sockets. If possible, use a valueless 

~~ record to make initial tests. Turn the > 

Volume. control on the amplifier to mini- 
mum and switch on both units. Check that 
the front panel |.e.d. operates. 

It may be found convenient to use head- 
phones to monitor the sound. Start playing 
the record and gradually: increase the 
amplifier’s volume control. The music 
should be clearly heard. Compare the vol- 
ume with that playing similar music from a 
commercial CD. 

If the levels are not similar, adjust VR1 
and VR101 so that they are. If one channel 
is quieter than the other, adjust presets VR1 
or VR101 as appropriate to bring the weak- 
er channel to the level of the stronger one. 
This procedure ensures that the output is 
at line level and balanced between the 

Check the effects of the Scratch and 
Rumble switches. The rumble effect is very 
subtle and may not be noticed. Note that, as 
described, pressing the switches in pro- 
vides the anti-scratch and anti-rumble 


The frequency balance and anti-scratch 
effects could be altered by changing the 
value of resistors R6/R7 and R106/R107. 
By increasing the appropriate resistor val- 
ues slightly, the high-frequency response 
will be “cut” and vice versa. Beware — 
small changes make a lot of difference! 

An alternative method would be to 
replace resistors R7/R107 with a dual- 
ganged, panel-mounted, potentiometer 
(stereo). This would allow for continuous 
variation and switch S2 could then be 


When setting up the equipment to make 
CDs, the turntable should not be placed on 
the same surface as the computer (other- 
wise you could introduce hum due to 
vibration being transferred to the cartridge 
from the computer). Check that the 
turntable is “true” using a spirit level. 

Connect the preamplifier output to the 
line input of the PC sound card using twin- 
screened wire. Check that Left and Right 
channels are connected correctly. 

Layout of components inside the metal case. 




Cl [Be 
1d) -m sks 




Fig.4. Interwiring details from the printed circuit board to the rear panel mounted 

input and output phono sockets. 

Before making a recording, clean the 
surface of the disc using a proprietary anti- 
static cleaner. If it is very dirty, it will need 
special treatment to remove the debris 
which will have become deeply embedded 
in the groove. You could try playing it once 
or twice in an attempt to allow the stylus 
itself to remove the contamination. 


Check the stylus after every playing for 
any build-up of fluff and dirt. Leaving this 
will spoil the high-frequency response and 
also tend to cause the stylus to jump out of 
the groove. Use a proprietary stylus clean- 
ing kit (a fine brush and cleaning fluid). 
Styluses are easily damaged so follow the 
instructions and work carefully. 

Everyday Practical Electronics, September 2002 


Refer to your CD recording software 
instructions to make optimum sound level 
settings and make some tests using the old 
record. For your final recordings, you will 
probably be able to observe the file oscillo- 
scope-style. It is then possible to remove 
the heaviest clicks by highlighting and 
deleting them. 

However, this must be done with great 
care. Some CD recording software allows 
for sophisticated restoration work to be 
undertaken. Automatic click suppression' 
can be a problem because many sections of, 
the intended waveform are click-like. 

One final point — do not use the scratch fil- 
ter unless the result sounds better. This is 
because it gives a markedly “dull” effect. [_] 



30A 600V BRIDGE RECTIFIER. Order Ref: 

10 HOOK-UP LEADS. Assorted colours terminat- 
ing with insulated crocodile clips each end, each 
lead length 36cm. Order Ref: 2P459. 

PHILIPS STEPPER MOTOR. 12V 7-5 degrees. 
Order: Ref: 2P457. 

32uF 250V A.C. CAPACITOR. Order Ref: 2P452. 
4uF 440V A.C. CAPACITOR. Order Ref: 2P454. 
VERY POWERFUL MOTOR. Operates off 6, 9 or 
12V D.C. 2%in. long, 1¥in. diameter. Order Ref: 

items for 10kV working. Order Ref: 2P388. 
without lid. Order Ref: 2P391. 

4r.p.m. GEARED MAINS MOTOR. 115V but sup- 
plied with mains adaptor. Order Ref: 2P393. 
the veins wide spaced so suitable for transmitting. 
Order Ref: 2P394. 

supplied with mains adaptor. Order Ref: 2P396. 
20uF 375V CAPACITOR. Aluminium cased. Order 
Ref: 2P406. 

9V-0V-9V MAINS TRANSFORMER. 25VA, upright 
mounting with fixings. Order Ref: 2P408. 
COPPER CLAD BOARD. Size 15in. x 10in. x 
TAein. thick for making p.c.b.s etc. Order Ref: 

20W TWEETER. 4in. x 4in. 8 ohm by Goodmans. 
Order Ref: 2P403. 


W-SHAPED 30W FLUORESCENT. Philips, ideal 
name plate illluminator. Order Ref: 2P372. 



DIMMER SWITCH. Standard size flush place, 
state colour — red, yellow, green or blue. Order Ref: 

end, socket ends. Order Ref: 2P338. 

FIGURE-8 FLEX. Mains voltage, 50m. Order Ref: 

INFRA-RED UNIT. As fitted TV receiver. Order 
Ref: 2P304. 

L.C.D. CLOCK MODULE with details of other 
uses. Order Ref: 2P307. 

AM/FM RADIO RECEIVER with speaker but not 
cased. Order Ref: 2P308. 

Order Ref: 2P315. 

45A DP 250V SWITCH on Gin. x 3in. gold plate. 
Order Ref: 2P316. 

SOLAR CELL. 3V 200mA, 5 of these in series 
would make you a 12V battery charger, £2 each. 
Order Ref: 2P374. 

action, core is released when voltage is applied. 
Order Ref: 2P327. . 

HEATER PAD. Not waterproof. Order Ref: 2P329. 
DISK DRIVE. Complete less stepper motor, has all 
the electronics to control stepper motor. Order Ref: 

15V 320mA A.C. POWER SUPPLY. In case with 
13A base, ideal for bell or chime controller. Order 
Ref: 2P281. 

POWERFUL MAINS MOTOR with 4in. spindle. 
Order Ref: 2P262. 

20M 80 OHM TV COAX. Order Ref: 2P270. 
accessories. Order Ref: 2P215. 

6-DIGIT COUNTER. Mains operated. Order Ref: 

13A ADAPTORS. Take two 13A plugs, pack of 5, 
£2. Order Ref: 2P187. 

3-CORE 5A PVC FLEX. 15m. Order Ref: 2P189. 

7-SEGMENT NEON DISPLAYS. Pack of 8. Order 
Ref: 2P126. 

extension. Order Ref: 2P94. 

13A SWITCH SOCKET on satin chrome plate. 
Order Ref: 2P95. 

500 STAPLES. Hardened pin, suit burglar alarm or 
telephone wire. Order Ref: 2P99. 

PAD SWITCH for under carpets, doormats etc. 
Order Ref: 2P119. 

TITESTER, complete 
with backrest to stand it 
and hands-free test 
prod holder. This tester 
measures d.c. volts up 
to 1,000 and a.c. volts 
up to 750; d.c. current 
up to 10A and resist- 
ance up to 2 megs. Also 
tests transistors and 
diodes and has an 
internal buzzer for con- 
tinuity tests. Comes 
complete with test prods, battery and instructions. Price 
£6.99. Order Ref: 7P29. 

ates voltages which enable you to read insulation directly in 
megohms. The multimeter has four ranges: AC/DC volts, 3 
ranges DC milliamps, 3 ranges resistance and 5 amp range. 
These instruments are ex-British Telecom but in very good con- 
dition, tested and guaranteed OK, probably cost at least £50 
each, yours for only £7.50 with leads, carrying case £2 extra. 
Order Ref: 7.5P4. 

REPAIRABLE METERS. We have some of the above testers 
but slightly faulty, not working on all ranges, should be 
repairable, we supply diagram, £3. Order Ref: 3P 176. 

BT TELEPHONE EXTENSION WIRE. This is proper heavy 


_ duty cable for running around the skirting board when you 

want to make a permanent extension. Four cores properly 
colour coded, 25m length only £1. Order Ref: 1067. 

HEAVY DUTY POT. Rated at 25W, this is 20 ohm resistance 
so it could be just right for speed controlling a d.c. motor or 
device or to control the output of a high current. Price £1. 
Order Ref: 1/33L1. . 

1mA PANEL METER. Approximately 80mm x 55mm, front 
engraved 0-100. Price £1.50 each. Order Ref: 1/16R2. 

D.C. MOTOR WITH GEARBOX. Size 60mm long, 30mm 
diameter. Very powerful, operates off any voltage between 6V 
and 24V D.C. Speed at 6V is 200 rpm, speed controller avail- 
able. Special price £3 each. Order Ref: 3P108. 

FLASHING BEACON. Ideal for putting on a van, a tractor or 
any vehicle that should always be seen. Uses a Xenon tube 
and has an amber coloured dome. Separate fixing base is 
included so unit can be put away if desirable. Price £5. Order 
Ref: 5P267. 

plugs into a 13A socket, is really nicely boxed. £2. Order Ref: 
2P733. ; 

MOTOR SPEED CONTROLLER. These are suitable for D.C. 
motors for voltages up to 12V and any power up to 1/6h.p. 
They reduce the speed by intermittent full voltage pulses so 
there should be no loss of power. Made up and tested, £18. 
Order Ref: 20P39. 

BALANCE ASSEMBLY KITS. Japanese made, when 
assembled ideal for chemical experiments, complete with 
tweezers and 6 weights 0-5 to 5 grams. Price £2. Order Ref: 

CYCLE LAMP BARGAIN. You can have 100 6V 0-2A MES 
bulbs for just £2.50 or 1,000 for £20. They are beautifully 
made, slightly larger than the standard 6-3V pilot bulb so 
they would be ideal for making displays for night lights and 
similar applications. 

SOLDERING IRON, super mains powered with long-life 
ceramic element, heavy duty 40W for the extra special job, 
complete with plated wire stand and 245mm lead, £3. Order 
Ref: 3P221. 



We have thousands of relays 
of various sorts in stock, so if 
you need anything special 
give us a ring. A few new 
ones that have just arrived 
are special in that they are 
plug-in and come complete 
with a special base which 
enables you to check volt- 
ages of connections of it 
without having to go under- 
neath. We have 6 different 
types with varying coil volt- 
ages and contact arrangements. 

Coil Voltage Contacts Price Order Ref: 
12V DC 4-pole changeover £2.00 FR10 
24V DC 2-pole changeover £1.50 FR12 
24V DC 4-pole changeover £2.00 FR13 

Prices include base 
MINI POWER RELAYS. For p.c.b. mounting, size 28mm x 
25mm x 12mm, all have 16A changeover contacts for up to 
250V. Four versions available, they all look the same but have 
different coils: 

6V — Order Ref: FR17 24V — Order Ref: FR19 
12V — Order Ref: FR18 48V — Order Ref: FR20 
Price £1 each less 10% if ordered in quantities of 10, same 
or mixed values. 
each, which is a real bargain considering many firms 
charge as much as £2 each. These are in packs of 10, 
coupled together with an output lead so are a 12V unit 
but easily divideable into 2 x 6V or 10 x 1-2V. £2.50 per 
pack, 10 packs for £25 including carriage. Order Ref: 

’ 4 CIRCUIT 12V RELAY. Quite small, clear plastic enclosed 

and with plug-in tags, £1. Order Ref: 205N. 

just arrived is extra small with a 12V coil and 6A changeover 
contacts. It is sealed so it can be mounted in any position or 
on a p.c.b. Price 75p each, 10 for £6 or 100 for £50. Order 
Ref: FR16. 

GEARBOXx. Motor is mounted 
on the gearbox which has 
interchangeable gears giving 
a range of speeds and motor 
torques. Comes. with full 
instructions for changing 
gears and calculating speeds, 
£7. Order Ref: 7P26. 


24V STEREO POWER SUPPLY. Mullard. Order Ref: 

UP TO 90 MIN 25A SWITCH. Clockwork. Order Ref: 

POWERFUL MAINS MOTOR. 1%2in. stack, double 
spindle. Order Ref: 2P55. 

p.s.u., also reverse. Order Ref: 2P3. 

MAINS TIME AND SET SWITCH. 25A, up to 6 hours 
delay. Order Ref: 2P9. 

A.C. Order Ref: 2P19. 

TWIN EXTENSION LEAD. Ideal lead lamp, Black & 
Decker tools, etc., 20m. Order Ref: 2P20. 

MAINS COUNTER. Resettable, 3 digit. Order Ref: 

ILLUMINOUS PANEL, 16 x 16V bulbs to light coal 
effect heater, etc. Order Ref: 2P317. 

TIME AND SET SWITCH. 15A mains. Order Ref: 

D.C. VOLT REDUCER. 12V-6V, fits into car lighter 

_ socket. Order Ref: 2P318. 

CAPACITOR, VARIABLE. For tuning AM/FM with “in. 
spindle. Order Ref: 2P269. 

CAPACITOR, VARIABLE. 0-0005 solid dia. ‘%in. 
spindle. Order Ref: 2P268. 

COPPER CLAD BOARD. 15 x 10 x ‘he for 
Order Ref: 2P409. 

25V-0V-25V MAINS TRANSFORMER. 112A. Order 
Ref: 2P410. 

20V-0V-20V DITTO. Order Ref: 2P411. 

80mm x 46mm x 65mm METAL PROJECT. BOX with 
rubber feet, supplied as flat pack. Order Ref: 2P412. 
24V 1A MAINS TRANSFORMER. Order Ref: 2P413. 
12V 2A MAINS TRANSFORMER. Order Ref: 2P414. 
80 OHM COAX. Extra thin, 15m. Order Ref: 2P417. 




ROTARY SWITCH. 40A with porcelain pointer control 
knob. Order Ref: 2P419. 
AIR-SPACED TUNING CAP with one section 350pF, 
the other 250pF, with %in. spindle and slow motion 
drive. Order Ref: 2P422. 
DITTO but 150pF and 300pF. Order Ref: 2P423. 
TRANSMITTER TUNER. 2-gang, wide spaced. Order 
Ref: 2P425. 
A.C. 250V CAPACITOR. 20uF. Order Ref: 2P427. 
12V P.S.U. 800mA D.C. with pins for shaver socket. 
Order Ref: 2P428. 
MAINS MOTOR WITH GEARBOX giving 6 revs per 
hour. Order Ref: 2P430. | 
CLOCKWORK TIMESWITCH with scale settable up 
to 6 hours. Order Ref: 2P432. 
OLD TIME RADIO CASE for the Good Companion. 
Order Ref: 2P436. 
4 OHM TWEETER. 20W, by Goodmans. Order Ref: 
BT ENGINEER’S PHONE. Unused but missing some 
parts, ideal for stripping. Order Ref: 2P439. 
Ref: 2P440. . 
MIN! MOTOR WITH GEARBOX, giving 16 r.p.m. Order 
Ref: 2P442. 
ICESTAT. Cuts in just above freezing. Order Ref: 
BALANCE KIT with gram weights for chemical exper-: 
iments etc. Order Ref: 2P444. 
Vu METER. 40mm square. Order Ref: 2P445. 
SLYDLOK FUSE. 30A. Order Ref: 2P447. 
KV CAP. 1uF 1500V. Order Ref: 2P448, 
9V P.S.U. 1A D.C., plugs into 13A socket.. Order Ref: 
6-CORE 3A FLEX. 15m. Order Ref: 2P451. 

Send cash, uncrossed PO, cheque or quote credit 
card number. If order is £25 or over deduct 10% but 
add postage, £3.50 if under 2 kilo, £6 if under 4 kilo. 

Sa Beane) 
Pilgrim Works (Dept.E.E.) 
Stairbridge Lane, Boliney 

Sussex RH17 5PA 
Telephone: 01444 881965 


Everyday Practical Electronics, September 2002 



wohn Becker addresses some 

of the general points readers 

have raised. Have you anything 
interesting to say? 

Drop us a line! 


Dear EPE, 

I’ve been building your PIC Controlled 
Intruder Alarm (Apr ’02) — great application! It 
seems, though, that you can only arm the alarm 
when the entry zone is set-up to be normally- 
open, is this so? 

In your article you suggest feedback would be 
welcome on the use of the RB4 interrupt for the 
panic switch. I have linked pins of the S3 con- 
nector but can still trigger the panic event by 
generating mains noise, even pulling the plug out 
and switching to battery power sometimes gen- 
erates the event. I’m planning to add mains sup- 
pression etc. 

Mark Jones, 
via email 

Feedback is always welcome Mark, thanks. 
The entry zone restriction was not intentional, 

but in practice I have never encountered a situa- 
tion where entering the main door zone could 
require a choice between normally-open and 
normally-closed contacts. 


Dear EPE, 

I am currently doing my final year project on 
a home security system which involves a 4 x 3 
matrix keypad, PIR sensor, magnetic switch and 
glass break detector. I’m using a PIC16F84 and 
PICBasic to write the software. Can you please 
give me some advice? 

Brendon, Malaysia, by email 

Sorry to disappoint you Brendon, but we can- 
not give specific advice for reader’s own designs, 
but you might find my PIC Controlled Intruder 
Alarm of April ’02 of interest. That uses a 
matrixed keypad. 

Everyday Practical Electronics, September 2002 


A 3'2 digit pocket-sized |.c.d. multime- 
ter which measures a.c. and d.c. volt- 

age, u.c. current and resistance. It can 

also test diodes and bipolar transistors. 

Every month we will give a Digital 
Multimeter to the author of the best 
Readout letter. 


Dear EPE, 

I know that most of your projects that use 
microcontrollers are based around PIC devices, 
but I just want to let any of your readers who use 
the 8051 microcontroller, or its many derivatives, 
know about a very good freeware open source | 
ANSI compliant optimising C compiler which I 
have been using for a few months, now called 
SDCC. It’s available for download from 

There are several discussion forums for its 
users also on the same site. It can also be target- 
ed at Z80, Gameboy Z80, AVR and PIC14x 
microcontrollers, and comes with a freeware 
8051 software simulator. 

Keep up the good work on your magazine, I 
have been a reader since I was a schoolboy 

Jez Smith, by email 

Thanks Jez, undoubtedly we have some read- 

-ers who are 8051 users as well as PIC addicts. 

And thanks too for your continued interest in 


I have taught myself PICBasic and have a 
great interest in microcontrollers. What I would 
like to. know is what industries use Basic 
Controllers and is it hard to start a career using 
and programming them? Any advice would be 
greatly appreciated. | 

Alex, via email 

I suspect that in general industry does not use 
PICBasic types of program, preferring the more 
universally used assembler codings in various 
forms. Readers — what are your opinions? 


Dear EPE, 

I am from Les Quennevais school in Jersey. 
For my business GCSE project I am going to 
make a photoelectric smoke detector, carbon 
monoxide detector and heat detector for the deaf. 
I am wondering if you could send me some cir- 
cuit diagrams or tell me your suppliers as it 

~ would largely help me in my project. Any infor- 

mation that you could give would be very helpful 
Alan Morris, 
via email 

Our Teach In 2002 series looked at smoke 
detection in the June ’02 issue, back issues can 
be ordered via our Online site, or according to 
the information published in each EPE issue. We 
have not done other smoke detectors in recent 
years. . 

Dear EPE 
I am having problems finding the LM13600 
transconductance op.amp for the StyloPIC of 
July 2002, the RS 304-453 is now listed as “no 
longer stocked”. Do you know what other device ~ 
could be used as an alternative please? 
Mike Mackellow, 
via email 

You can use the LM13700 instead as a direct 
replacement — no mods needed. 



Dear EPE, 

Following on from your StyloPIC in July 
"02, you might be interested in some info on 
the original. There were three variations of the 
pocket model — standard, treble and bass. The 
treble and bass models being respectively an 
octave higher or lower (mine is the standard 
model). Its big brother, the 350S, had many 
extra features such as short or long envelope, 
staccato, two speed vibrato, wah-wah, and 
eight voices. 

An innovative feature is a light sensor (I.d.r.) 
for hand control of vibrato or wah-wah. It also 
has two styluses (for playing “chopsticks”?). An 
external amplifier was also available for either 
instrument, with tone and tremolo controls. On 
the technical side, the circuit diagram for the 
pocket version is in the back of the instruction 

Tone generation is by a programmable uni- 
junction transistor so the waveform would be 
pulsed, however it is modified by what looks like 
a diode pump monostable so the mark-space 
ratio would vary depending on the note frequen- 
cy (and presumably the harmonics generated). 
So the output waveform would be something like 
a square wave with slow rise and fall times. 
Vibrato is generated by a low frequency phase 
shift oscillator to vary the programming voltage 
of the unijunction transistor. 

I know John Becker likes to recycle his soft- 
ware so here is something to consider in a future 
incarnation. It gives greater flexibility of the out- 
put waveform. And, of course, you can have 
multiple waveform tables. This is only an exam- 
ple, other changes may be needed for it to work 

movwf PORTA 
goto MAIN 
WAVEFORM: andlw $7F _; Sinewave + 2nd harmonic 
movwf PCL; 128 entries, amplitude 
0 to 63 


DT 00,00,00,00,00,01,02,04,06,08,11,13,16,19,22,26 
DT 29,32,35,39,42,44,47,49,52,54,55,57,58,59,59,59 
DT 60,60,60,60,60,59,59,59,58,59,59,57,57,57,57,57 
DT 58,58,59,59,60,60,61,61,62,62,63,63,63,63,63,63 
DT 62,61,60,59,58,56,55,53,51,49,47,45,43,41,39,37 
— DT 35,33,32,31,30,29,29,28,28,29,29,30,31,32,33,34 
DT 35,36,38,39,40,41,42,43,43,43,43,42,42,41 39,38 
DT 36,34,32,29,27,24,21,19,16,13,11,08,06,04,03,01 
; (DT is “Define Table of retlw’s” in MPASM) 

Peter Hemsley, 
via email 

Thanks Peter. The technical stuff I did not find 
on the web. The table concept looks interesting. I 
don’t know that I’ll ever upgrade StyloPIC — but 
who knows?! 


Dear EPE, 

PICs are not my strong point! However, I’ve 
started to look at the code for your PIC 
Controlled Intruder Alarm (Apr ’02) with a view 
to modifying it to suit my own purposes. Do you 
have a flow chart that you could send me? 

Trevor Brearley, 
- Via email 

No, sorry Trevor, I don’t do flow charts for my 
software — I keep concepts in my head and work 
to those! 

Readers who do like to work with flow 
charts will probably be interested in the Flow 
Code for PICmicro CD-ROM that’s available 
via our CD-ROM pages in this issue, and in 

Terry de Vaux Balbirnie’s review of it, also in| 

this issue. 


Dear EPE, 

I am building the BioPIC Heartbeat Monitor 
(Jun ’02) and need to know the order code for 
Boots’ lead pack, together with the information 


where to order from abroad. The TENS replace- 
ment electrode pads you specify are easy to find 
at almost any Boots shop, but the staff there 
know nothing about leads, nor how to order. I’ve 
tried at several Boots shops on my last trip to 

Cristian, via email 

Mine came from Boots in Wimborne. I don’t 
know the order code, they were being supplied as 
normal stock items. If you can’t get any, use flex- 
ible wire with crocodile clips to clip onto the 
chest pads. They don’t need screening. You could 
try asking Boots HQ via email ( 
will provide a web address). 

Dear EPE, 

Readers might be interested in my PIC pro- 

gram for use with the TLC548/9 8-bit serial ana- 
logue-to-digital converter. I use file registers 
COUNT and TEMP as sort of “standard” regis- 
ters, COUNT for timing etc and TEMP as a sort 
of second W. It helps me get a mental view of my 

In the program this routine comes from, 
COUNT has previously been reset through 
DECFSZ, so I can get away with BSF 
COUNT,3. I have run this at 6MHz without 

problem, and it should go faster. The A-D. value 

is stored in file UNIT. 

hold value to 

; set count to shift 
8 bits (make 
sure that 
COUNT cleared 
before this sec- 
tion or use 

~ MOVLW etc) © 

; move bits one 
place left & 
store new value — 
in UNIT 

; set 0 value 
before Portb,0 
bit test 

; set A2D clock 
pin high, release 
bit for transfer 

; is bit 0 (DOUT) 
set ? 

; no, then leave 
UNIT bit 0 value 
as 1S 

; yes, set bit 0 of 







NEXT1: BCF PORTB,6 ; clear clock pin 
GOTO FETCH ; no, get another 
; yes, 8 bits 
~ clocked out & 
held in UNIT, 
set CS line to 
get new value 


Graham Card, 
via email 

Useful, Graham, thank you — I’ve put it in the 
PIC Tricks folder on our ftp site. 

Dear EPE, . 

I’ve been reading Humphrey Berridge’s 

Freezer Alarm in the May ’02 issue, and I’m 
extremely impressed with the low component 
count for the functionality achieved, but I’d like 
to make a suggestion: 

The piezo sounder needs to be as loud as pos- 
sible, but it’s only being fed with 5V pk-pk from 
pin GP4 to ground. If you connect the sounder 
between GP4 and GP5, and feed GP5 with an 
inverted signal, you will get 10V p-p drive in a 
bridge configuration — twice the voltage, at no 
extra cost! 

; clear CS line to — 

The only changes required are to the sweep2 
and sweep3 routines: 

; Output high 
; output2 low — added 

sweep2 _ bsf output 
bcf output2 
decfsz freq,f 
goto sweep2 
movfw nfreq 
movwf freq 

sweep3 bcf output 
bsf output2 
decfsz freq,f 
goto sweep3 

; output low 
5 Output2 high — added 

Plus an extra define line: 
#define output2 gpio,5 ; inverted 0/p to piezo 
Nigel Goodwin, via email 

| Thanks Nigel! 


Dear EPE, 

I am studying GCSE Electronics. My father 
has been purchasing EPE since 1994 and is still 
enjoying each new edition. In the April 95 issue 
I came across the National Lottery Predictor 
project and am wondering if you could please | 
send me as much information on that topic as 
possible to further my knowledge and passion. 

| Gopyr, via email 

_ So sorry, but we cannot provide additional 
material for any published design. Regarding 
building a circuit from 1995, we normally advise 
against attempting to build a design that is over 
five years old since parts could well have 
become obsolete during that time. 

In this particular case, the p.c.b. is no longer 
available, nor will you be able to obtain the pro- 
grammed PIC as we are no longer in touch with 
the authors, and they did not sell us the copyright 
to their software (that was before we began to 
insist that all project software must be made 
freely available to readers). 


I am designing an “Earth Resistivity Logger” 
for archeological use, inspired by Robert Beck’s 
Earth Resistivity Meter of Jan/Feb ’97. Mine is 
PIC controlled and will have its own non-volatile 
memory (data stays held even after switch off); 
possibly a graphics l.c.d. may show rough details 
of reading values as grey scale; serial interface 
for connection to PC for deeper analysis. 

I am not an archeologist and am approaching 
the design purely as an electronic problem to be 
solved — send an output signal, retrieve it from a 
distance and store the value. I am in communi- 
cation with a local archeological society, but I 
would be pleased to hear from any EPE readers 
involved in this field, with special regard to the 

@ How many reading samples do you normally 
take on a site in one main session? 

@ How many samples would you like the logger 
to store before download to PC? 

@ Is powering it from a 12V car battery ade- 
quate, or do I need +18V as Robert had? 

@ What probing techniques do you use? [’'m 
assuming the twin-probe technique is best, as 
described by Robert. 

@ What maximum probe separation distance do 
you use? 

@ How deep do you insert the probes? 

@ Is a signal frequency of 137Hz as used by 
Robert the best to use? 

@ In your experience, how likely is it that 5OHz 
mains frequency is likely to occur on a site 
being surveyed, and would thus need to be fil- 
tered out in some way? 

@ Do you always plot the site squares in the 
same regular order, or would you prefer to 
sample in random order, telling the logger the 
square number being sampled? 

Any answers would be appreciated, my email 

Everyday Practical Electronics, September 2002 

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Everyday Practical Electronics, September 2002 673 


Robert Penfold looks at the Techniques of Actually Doing It! 

ONCERNS about finished projects 

failing to work are probably the 
main reason for would-be constructors 
failing to “take the plunge”. It is not a 
major concern for those with years of 
project building experience because 
they have the technical knowledge, 
equipment, and know-how to deal with 
practically any problem. The opposite is 
true for beginners who, on the face of it, 
have little chance of dealing with pro- 
jects that refuse to work. 

Keep it Simple 

In reality the situation for beginners i is 
better than it might seem. Provided you 
start with something reasonably simple 
and follow the instructions carefully 
there is a good chance of success. Pre- 
publication checking for both books and 
articles containing electronic projects 
has increased over the years, and this 
has greatly reduced the chances of 
being led astray by printing errors. On 
the rare occasions that an error does 
creep in to an EPE article it is usually 

spotted quite early and corrected one > 

or two issues later. 

In general, the complexity of modern 
projects is greater, but your chances of 
failure if the instructions are followed “to 
the letter’ are much less than they 

were. Like any creative skill, electronic 

project construction would not be a 
worthwhile hobby if perfect results were 
guaranteed every time with no skills 
required. You have to be prepared to 
put in some effort and try to go about 
things the right way. 

It is worth repeating the importance 
of choosing a project that is within your 
Capabilities. It is tempting to dive 
straight in with a project that will 
impress your friends, but the more 
complex the project the greater the risk 
that you will make a mistake. In the past 
it was not unusual to receive letters 
from readers having problems with 
projects that they clearly did not under- 
stand at all. 

You do not need to know how a 
project works in order to build it suc- 
cessfully, but you: do need to have a 
proper understanding of what it is sup- 
posed to do and how it is used. 
Something like a household gadget is a 
more appropriate starting point than an 
advanced piece of test equipment 
where you need a degree in physics in 
order to switch it on! 

Fortunately, letters from readers who 
have “bitten off more than they can 
chew” are relatively rare these days, 
but it is still a problem to take seriously. 

Mains Point 
The mains supply is potentially 

lethal, as are projects that connect to | 

it. Mains power projects are only suit- 
able for those with a reasonable 
amount of experience at project con- 
struction. Even if a project is very 


simple, if it connects to the mains sup- 
ply it is certainly not suitable for a 

Start with projects that are battery 
powered. If you should make a serious 
blunder it is possible that one or two of 
the components will be damaged, but 
you should be perfectly safe. In most 
cases all the components will survive 
the experience as well. 

The two main construction methods 
used in modern projects are stripboard 
and custom printed circuit boards 
(p.c.b.s). While both types of board are 
pretty straightforward to use, custom 
printed circuit boards represent the 
more foolproof option. Stripboard is a 
multi-purpose circuit board that has a 
regular matrix of holes, and in most 
projects only a few percent of these are 
actually used. 

As its name suggests, a custom 
printed circuit board is specifically 
designed for a particular circuit and 
normally has just one hole per leadout 
wire or pin. With a custom board there 
is relatively little risk of making a mis- 
take in the first place, and any errors 
that should creep in are likely to be 
spotted almost immediately. With strip- 
board there are hundreds of unused 
holes that are good at disguising mis- 
takes, and some very careful erent 

_ is needed to detect them. 

Bridging the Gap 

Having chosen a suitable project and 
put it together with due diligence, what 
do you do if the finished unit fails to 
work? When a newly constructed pro- 
ject is clearly failing to work properly it 
is not a good idea to leave it switched 

Leaving a faulty project switched on 
could result in damage to some of the 
components, and the semiconductors 
are particularly vulnerable. Always 
switch off faulty projects immediately 
and then recheck the component lay- 
out, wiring, etc. 

The prudent project builder checks 
all this sort of thing very carefully dur- 
ing construction, and spotting errors 
early can save a lot of hassle latter. In 
order to properly check the unit you 
may have to partially dismantle it in 
order to get proper access to the circuit 

Years of practical experience sug- 
gest that the vast majority of problems 
are due to “short-circuits” between cop- 
per tracks on the underside of the cir- 
cuit board. This is not exactly a new 
problem, but the intricacies of modern 
boards make it even more problematic 
than in the past. 

Unless the board is coated with a 

solder resist that is designed to dis- | 

courage solder bridges, it is likely that 
several will be produced per circuit 
board. Most of these bridges will be 

spotted while you are constructing the’ 

board, and in most cases they are eas- 
ily removed using the bit of the solder- 
ing iron. If there is a lot of excess solder 
it is better to use a desoldering tool, 
and an inexpensive desoldering pump 
is ideal for this application. It is advis- 
able to remove as much solder as pos- 
sible and then redo any joints that have 
been desoldered. 

Hidden from View 

The more difficult problem is minute — 
trails of solder that are often difficult or 
impossible to see with the naked eye. 

~ The situation can be made more diffi- 

cult by the trails being hidden under 
excess flux from the solder. This tends — 
to get liberally splattered across the 
underside of circuit boards during con- 
struction. There are various products 
that can be used to thoroughly clean 
the flux from boards, but vigorous 
brushing with a small brush such as an 
old toothbrush seems to do the job well 
enough. | 

A good joint, 
Solder failed to nice and shiny. 


A “dry” 

Photos courtesy Alan Winstanley’s Basic Soldering Guide 

Good eyesight is not sufficient to 
guarantee that any solder bridges will 
be spotted. Some form of magnifier 
now has to be considered part of the 
standard toolkit for electronic project 
construction, and even a small magni- 
fying glass will greatly increase the 
chances of detection. 

An 8x or 10x loupe (also sold as 
lupes) is better though. The inexpen- 
sive types sold as photographic acces- 
sories for viewing slides and negatives 
are perfectly adequate for the present 

Provided the board is thoroughly 
cleaned first, a careful visual check 
using a magnifier should reveal any sol- 
der bridges. As solder bridges occur so 
often it is a good idea to clean and visu- 
ally inspect all completed circuit boards 
prior to installing them in the case. 

Hot Spots 
Dubious soldering is a common 
cause of problems, particularly 

amongst beginners. Soldering is like 
any skill, and it is a case of “practice 
makes perfect”. The more projects you 
build the more proficient you will 
become at completing soldered con- 
nections. There is insufficient space 
here for a “soldering tutorial’, but a 

Everyday Practical Electronics, September 2002 


good one is available at the EPE web 
site. Some soldering irons and solder- 
ing kits are supplied with detailed 
instructions, and it is well worthwhile 
studying these. 

Probably the most common cause of 
so-called “dry” joints is the soldering 
iron being left unused for a few minutes 
before starting a new batch of connec- 
tions. If there is a substantial amount of 
solder left on the bit, any flux in it will 
burn away and it will probably start to 
oxidise. If you produce the next joint 
without cleaning the end of the bit first, 
the joint will contain a significant pro- 
portion of old solder, which may not 
flow over the joint properly. | 

The resultant joint might look plausi- 
ble and could seem to have good 
mechanical strength as well. However, 
joints of this type usually provide only 
intermittent electrical contact or no con- 
tact at all, and are relatively weak 

_ Shining Example 7 

Always make sure that the bit is tinned 

with fresh solder prior to making joints. 
Practice soldering with some bits of wire, 
a few resistors, and a scrap of stripboard 
before you start building projects. This 
will cost very little and will greatly 
enhance your chances of success. 

Checks with a continuity tester or the 
continuity function of a multimeter 
should locate dry joints, but thoroughly 
checking even a small circuit board can 
be quite time consuming. Large 
amounts of excess flux are sometimes 
indicative of a bad joint, but this is of no 
help once the board has been cleaned. 

Good joints normally have a char- 
acteristic mountain shape and the 
surface of the solder is very shiny. 
“Dry” joints are often more spherical 
in shape and the solder tends to have 
a relatively dull surface, possibly with 
some crazing. 

Clean Break 

If any joints look suspicious it is prob- 
ably worthwhile desoldering them and 
then re-soldering them. Before trying 
again it is a good idea to have a close 
look at the two surfaces. These days it 
is unusual for dirt or corrosion on one of 
the surfaces to cause problems. 
Modern components are less vulnera- 
ble to corrosion on the leadout wires 
and tags, and the flux in electrical sol- 
ders is very efficient at dealing with 

However, there can still be occasion- 
al problems though, and if there is any 
sign of contamination it is a good idea 
to clean both surfaces before redoing 
the joint. The best way to clean the sur- 
faces is to gently scrape them with the 
small blade or a penknife, a miniature 
file, or something of this type. 

The driest joint of all is the one you 
forget to do! Missing joints are usually 
fairly obvious with custom printed cir- 
cuit boards, but can be difficult to see 
with stripboard where there are numer- 
ous unused holes and no pads as 
such. Firmly pulling on resistors, capac- 
itors, diodes, etc., will reveal any miss- 
ing joints, or ineffective joints that look 

Fig.1. The wide band indicates the 
cathode (k) leadout of multi-band 

Heat of the Moment 

Apart from semiconductors, modern 
components are reasonably tolerant of 
heat. However, it is still possible that 
damage will occur if you take too long 
to complete joints. Heat damaged com- 
ponents usually show some obvious 
signs of damage, such as a darkening 
in colour or being slightly misshapen. 
Always replace any “off colour” or 
deformed components, or any compo- 
nents that show significant signs of 
physical damage. 

Integrated circuits (i.c.s) are mostly 
fitted in holders, but transistors and 
diodes are often connected directly to 
the circuit board. Always take extra 
care when fitting these in place. As 
pointed out previously, it is a matter of 
“practice makes perfect’, and you can 
avoid a lot of problems by learning to 
solder quickly and neatly before dealing 
with transistors and diodes. 

Try and Try Again — 

Having thoroughly checked both 
sides of the board and made any nec- 
essary repairs it is time to reassemble 
the project and test it again. Thoroughly 
check the hard wiring against the wiring 
diagram, as it is relatively easy to make 
mistakes here. If the project still does 

not work, the most likely explanation is 

that you have missed an error in the 
wiring or on the circuit board. 

With this type of thing there is a ten- 
dency to blame others and not accept 
that you could have made a mistake. In 
reality it is easy to make the odd mis- 
take here and there, and even “old 
hands” make the occasional error. 

Start by checking that every compo- 
nent on the circuit board is in the right 
place and has the correct value. Work 
through the components methodically 
making sure that none of them are 
overlooked. If you have managed to 
miss out a component, this error should 
then come to light. With stripboard con- 

_ Struction make sure that any link wires 

are present and correct. 

Ideally you should get someone else 
to check the unit against the construc- 
tion diagrams. A fresh pair of eyes 
might spot something that you have 
consistently overlooked. 

Wrong Connection 

The components that must be fitted 
the right way round are the most likely 
to give problems. Layout diagrams and 

Everyday Practical Electronics, September 2002 

the markings on components such as 
diodes and electrolytic capacitors are 
usually quite explicit, so any errors 
should be easily spotted. 

One exception is the type of diode 
that has several bands rather than one 
at the cathode (“k” or “+”) end of the 
component. These have had something 
of a renaissance in recent times, so you 
may well encounter them. The bands 
indicate the type number using a varia- 
tion on the resistor colour code. A wider: 
band at that end of the body (Fig.1) 
indicates the cathode (k) lead. 

Light emitting diodes (l.e.d.s) can 
also be problematic. If a project works 
apart from a l.e.d. indicator, it is odds- 
on that the l.e.d. is simply connected 
the wrong way round. 

A Pressing Connection 

Before too long practically everyone 
makes the classic mistake of forgetting 
to switch on the project or omitting that 
all-important component — the battery. 
Battery connectors have always been 
notoriously unreliable. Try pressing the 
connector firmly onto the battery to see 
if it makes the project burst into action. 
Slightly compressing the female con- 
nectors with pliers usually gets a loose 
clip to work reliably. 

Battery holders for 1-5V cells are 
also something less than totally reli- 
able. Ensure that the terminals of the 
batteries and the holder are clean by 
gently removing any contamination with 
fine sandpaper. 

Multi-checks - 

A cheap multimeter is useful for 
checking that the battery voltage is 
actually getting through to the circuit 
board. It can also be used to check that 
the battery is in a usable state. 

Even if you do not have much techni- 
cal knowledge, a multimeter can still be 
useful for numerous basic checks. For 
example, it can be used for making 
continuity checks on switches, which 
may not operate in quite the way you 
think they do? 

Have you confused the “on” and “off” 
settings? Often when a project seems 
to be working irrationally it is just that 
one of the switches does not function 
as expected. The high and low ranges 
are transposed, or something of this 
A multimeter is also useful for check- 
ing cables for short-circuits or broken 
leads, checking that that plugs and 
sockets connect together properly, etc. 
Even some of the cheaper digital types 
now have the ability to check resistors, 
transistors, diodes, and capacitors, 
which is clearly more than a little use- 
ful. A multimeter is a piece of equip- 
ment that no project builder should be 

Because modern components are 
very reliable you are unlikely to have 
a failure caused by a dud component. 
If you get. everything connected 
together properly your projects will 
work, and it helps to keep this in 
mind. Of course, the projects will 
never work if you do not pluck up the 
courage to “take the plunge” and 
actually build them. 







Logic Probe testing 

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expanded in almost every area following a review of major syllabuses (GCSE, GNVQ, 
A level and HNC). It also contains both European and American circuit symbols. 
Sections include: Fundamentals: units & multiples, electricity, electric circuits, 
alternating circuits. Passive Components: resistors, capacitors, inductors, 
transformers. Semiconductors: diodes, transistors, op.amps, logic gates. Passive 
Circuits. Active Circuits. The Parts Gallery will help students to recognise common 
electronic components and their corresponding symbols in circuit diagrams. 

Included in the Institutional Versions are multiple choice questions, exam style 
questions, fault finding virtual laboratories and investigations/worksheets. 


Complimentary output stage 


Virtual laboratory — Traffic Lights 

Filter synthesis 

Analogue Electronics is a complete learning resource for this most difficult 

branch of electronics. The CD-ROM includes a host of virtual laboratories, 

animations, diagrams, photographs and text as well as a SPICE electronic 

circuit simulator with over 50 pre-designed circuits. 

Sections on the CD-ROM include: Fundamentals — Analogue Signals (5 
sections), Transistors (4 sections), Waveshaping Circuits (6 sections). Op.Amps 
— 17 sections covering everything from Symbols and Signal Connections to 
Differentiators. Amplifiers — Single Stage Amplifiers (8 sections), Multi-stage 
Amplifiers (3 sections). Filters — Passive Filters (10 sections), Phase Shifting 
Networks (4 sections), Active Filters (6 sections). Oscillators — 6 sections from 
Positive Feedback to Crystal Oscillators. Systems — 12 sections from Audio 
Pre-Amplifiers to 8-Bit ADC plus a gallery showing representative p.c.b. photos. 

Digital Electronics builds on the knowledge of logic gates covered in Electronic 
Circuits & Components (opposite), and takes users through the subject of digital 
electronics up to the operation and architecture of microprocessors. The virtual 
laboratories allow users to operate many circuits on screen. 

Covers binary and hexadecimal numbering systems, ASCIl, basic logic gates, 
monostable action and circuits, and bistables — including JK and D-type flip-flops. 
Multiple gate circuits, equivalent logic functions and specialised logic functions. 
Introduces sequential logic including clocks and clock circuitry, counters, binary 
coded decimal and shift registers. A/D and D/A converters, traffic light controllers, 
memories and microprocessors — architecture, bus systems and their arithmetic logic 
units. Sections on Boolean Logic and Venn diagrams, displays and chip types have 
been expanded in Version 2 and new sections include shift registers, digital fault 
finding, programmable logic controllers, and microcontrollers and microprocessors. 
The Institutional versions now also include several types of assessment for 
supervisors, including worksheets, multiple choice tests, fault finding exercises and 
examination questions. 

Filters is a complete course in designing active and passive filters that makes 
use of highly interactive virtual laboratories and simulations to explain how filters 
are designed. It is split into five chapters: Revision which provides underpinning 
knowledge required for those who need to design filters. Filter Basics which is a . 
course in terminology and filter characterization, important classes of filter, filter 
order, filter impedance and impedance matching, and effects of different filter 
types. Advanced Theory which covers the use of filter tables, mathematics 
behind filter design, and an explanation of the design of active filters. Passive 
Filter Design which includes an expert system and filter synthesis tool for the 
design of low-pass, high-pass, band-pass, and band-stop Bessel, Butterworth 
and Chebyshev ladder filters. Active Filter Design which includes an expert 
system and filter synthesis tool for the design of low-pass, high-pass, band-pass, 
and band-stop Bessel, Butterworth and Chebyshev op.amp filters. | 


PCB Layout 

Electronics CADPACK allows users to 
design complex circuit schematics, to view 
circuit animations using a unique SPICE- 
based simulation tool, and to design 
printed circuit boards. CADPACK is made 
up of three separate software modules. 
(These are restricted versions of the full 
Labcenter software.) ISIS Lite which 
provides full schematic drawing features 
including full control of drawing 
appearance, automatic wire routing, and 
over 6,000 parts. PROSPICE Lite 
(integrated into ISIS Lite) which uses 
unique animation to show the operation of 
any circuit with mouse-operated switches, 
pots. etc. The animation is compiled using 
a full mixed mode SPICE simulator. ARES 
Lite PCB layout software allows 
professional quality PCBs to be designed 
and includes advanced features such as 
16-layer boards, SMT components, and 
an autorouter operating on user generated . 
Net Lists. 


Case study of the Milford 
Instruments Spider 

Robotics and Mechatronics is designed to 
enable hobbyists/students with little 
previous experience of electronics to 
design and build electromechanical 
systems. The CD-ROM deals with all 
aspects of robotics from the control 
systems used, the transducers available, 

-motors/actuators and the circuits to drive 

them. Full case study material (including 
the NASA Mars Rover, the Milford Spider 
and the Furby) is used to show how 
practical robotic systems are designed. 
The result is a highly stimulating resource 
that will make learning, and building 
robotics and mechatronic systems easier. 
The Institutional versions have additional 
worksheets and multiple choice questions. 
@ Interactive Virtual Laboratories 
@ Little previous knowledge required 
@ Mathematics is kept to a minimum and 
all calculations are explained 
@ Clear circuit simulations 

Hobbyist/Student ..........ssssssssscseeessesssssssesseeee e400 INC VAT 

: _ _ Institutional (Schools/HE/FE/Industry)..............£99 plus VAT 
Prices for each of the CD-ROMs above are: Institutional 10 user (Network Licence)..........£199 plus VAT 

(Order form on third page) BITS LICCNICE ve csscsscssivscrscssnsassernssnssaesssansasssssctaneeeckt Oe PIUS VAT 
(UK and EU customers add VAT at 17.5% to “plus VAT” prices) 



VERSION 2 PiCmicroMCU | ‘pi 

Suitable for use with the three software packages 

listed below. 

This flexible development board allows students to learn 
both how to program PiCmicro microcontrollers as well as 
program a range of 8, 18, 28 and 40-pin devices. For 
experienced programmers all programming software is 
included in the PPP utility that comes with the development 
board. For those who want to learn, choose one or all of the 
packages below to use with the Development Board. 

@ Makes it easier to develop PiCmicro projects 

@ Supports low cost Flash-programmable PlICmicro 


@ Fully featured integrated displays — 13 individual I.e.d.s, fee 
quad 7-segment display and alphanumeric I.c.d. display a 

@ Supports PiCmicro microcontrollers with A/D converters 

@ Fully protected expansion bus for project work 

@ All inputs and outputs available on screw terminal 

connectors for easy connection 


—— SOFTWARE - = 

£145 including VAT and postage 
12V 500mA plug-top PSU (UK plug) £7 
25-way ‘D’ type connecting cable £5 


Suitable for use with the Development Board shown above. 

(Formerly PiCtutor) 

Assembly for PICmicro microcontrollers V2.0 
(previously known as PiCtutor) by John 
Becker contains a complete course in 
programming the PIC16F84 PlCmicro 
microcontroller from Arizona Microchip. It 
starts with fundamental concepts and 
extends up to complex programs including 
watchdog timers, interrupts and sleep modes. 
The CD makes use of the latest simulation 
techniques which provide a superb tool for 
learning: the Virtual PlCmicro micro- 
controller. This is a simulation tool that 
allows users to write and execute MPASM 
assembler code for the PIC16F84 
microcontroller on-screen. Using this you 
can actually see what happens inside the 
PiCmicro MCU as each instruction is 
executed which enhances understanding. 
@ Comprehensive instruction through 39 
tutorial sections @ Includes Vlab, a Virtual 
PiCmicro microcontroller: a fully functioning 
simulator @ Tests, exercises and projects 
covering a wide range of PiCmicro MCU 
applications @ Includes MPLAB assembler 
@ Visual representation of a PliCmicro 
showing architecture and functions @ 
Expert system for code entry helps first time 
users @ Shows data flow and fetch execute 
cycle and has _ challenges (washing 
machine, lift, crossroads etc.) @ Imports 
MPASM files. 

Virtual PiCmicro 

‘C’ FOR PiCmicro 

The C for PlCmicro microcontrollers CD- 
ROM is designed for students and 
professionals who need to learn how to 
program embedded microcontrollers in C. 
The CD contains a course as well as all the 
software tools needed to create Hex code 
for a wide range of PlCmicro devices — 
including a full C compiler for a wide range 
of PiCmicro devices. 

Although the course focuses on the use of 
the PlCmicro microcontrollers, this CD- 
ROM will provide a good grounding in C 
programming for any microcontroller. 

@ Complete course in C as well as C 
programming for PICmicro microcontrollers 
@ Highly interactive course @ Virtual C 
PiCmicro improves understanding @ 

Includes a C compiler for a wide range of 
PiCmicro devices @ Includes full Integrated 
Development Environment @ Includes 
MPLAB software @ Compatible with most 
PiCmicro programmers @ Includes a 
compiler for all the PlCmicro devices. 

7 ee 

Minimum system requirements for these 
items: Pentium PC running Windows 98, 

NT, 2000, ME, XP; CD-ROM drive; 
64MB RAM; 10MB hard disk space. 


Flowcode is a very high level language 
programming system for PlCmicro 
microcontrollers based on_ flowcharts. 
Flowcode allows you to design and simulate 
complex robotics and control systems in a 

matter of minutes. 

Flowcode is a powerful language that uses 
macros to facilitate the control of complex 
devices like 7-segment displays, motor 
controllers and l|.c.d. displays. The use of 
macros .allows you to control these 
electronic devices without getting bogged 
down in understanding the programming 
Flowcode produces MPASM code which is 
compatible with virtually all PlCmicro 
programmers. When used in conjunction 
with the Version 2 development board this 
provides a seamless solution that allows 
you to program chips in minutes. 

@ Requires no programming experience @ 
Allows complex PICmicro applications to be 
designed quickly @ Uses international 
standard flow chart symbols (1SO5807) @ 
Full on-screen simulation allows debugging 
and speeds up the development process 
@ Facilitates learning via a full suite of 
demonstration tutorials @ Produces ASM 
code for a range of 8, 18, 28 and 40-pin 
devices @ Institutional versions include 
virtual systems (burglar alarms, car parks 
etc.). - 

Burglar Alarm Simulation 


Prices for each of the CD-ROMs above are: 
(Order form on next page) 


Institutional (Schools/HE/FE/Industry) 

Flowcode Institutional 

Institutional 10 user (Network Licence) 

Site Licence 

£45 inc VAT 
£99 plus VAT 
£70 plus VAT 
£249 plus VAT 
£599 plus VAT 

(UK and EU customers add VAT at 17.5% to “plus VAT” prices) 


EPE’s own Teach-in CD-ROM, contains 

he fll 12-partTeach-In series by John - “~ | FREE BOOK 
Becker in orm plus the Teach-In RP ie en 
interactive software covering all aspects Ne WITH TEACH-IN Counter 

of the series. We have also added Alan GRE CAT BU cle . ; 
Winstanley’s highly acclaimed Basic : 2000 CD-ROM pron 
Soldering Guide which is fully illustrated 
and which also includes Desoldering. 
The Teach-In series covers: Colour 
Codes and Resistors, Capacitors, 
Potentiometers, Sensor Resistors, Ohm’s 
Law, Diodes and L.E.D.s, Waveforms, 
Frequency and Time, Logic Gates, 
Binary and Hex Logic, Op.amps, 
Comparators, Mixers, Audio and Sensor 

Digital Works Version 3.0 is a graphical 
design tool that enables you to construct 
digital logic circuits and analyze their 
ae - behaviour. It is so simple to use that it will 
Sine wave relationship values Toole agg Soldering : take you less than 10 minutes to make your 

Amplifiers, Transistors, Transformers and . first digital design. It is so powerful that you 
Rectifiers, Voltage Regulation, Integration, Differentiation, 7-segment Displays, L.C.D.s, |e agus oo sues will never outgrow its capability ¢ Software 
Digital-to- -Analogue. GStiloscope Basics for simulating digital logic circuits ¢ Create 

Each part has an associated practical section and the series includes a simple PC 
interface so you can use your PC as a basic oscilloscope with the various circuits. 
A hands-on approach to electronics with numerous breadboard circuits to try out. 

£1 2.45 including VAT and postage. Requires Adobe Acrobat (available free from 
the Internet - 

FREE WITH EACH TEACH-IN CD-ROM — Electronics Hobbyist Compendium 80-page 
book by Robert Penfold. Covers Tools For The Job; Component Testing; Oscilloscope 

your own macros — highly scalable e Create 
your own circuits, components, and i.c.s @ 
Easy-to-use digital interface e Animation 
brings circuits to life @ Vast library of logic 
macros and 74 series i.c.s with data sheets 
@ Powerful tool for designing and learning. 
Hobbyist/Student £45 inc. VAT. 

Basics. Institutional £99 p/us VAT. 
Institutional 10 user £199 plus VAT. 
Site Licence £499 plus VAT. 
Two colourful animated courses for students on one CD-ROM. These cover Key Stage 3 and GCSE syllabuses. Key 
Stage 3: A pictorial look at the Electronics section featuring animations and video clips. Provides an ideal introduction COMPONENTS PHOTOS 

or revision guide, including multi-choice questions with feedback. GCSE: Aimed at the Electronics in many Design & 
Technology courses, it covers many sections of GCSE Electronics. Provides an ideal revision guide with Homework 
Questions on each chapter. Worked answers with an access code are provided on a special website. 

A high quality selection of over 200 JPG 
images of electronic 
components. This 

Single User £29 inc. VAT. Multiple User £39 plus VAT | selection of high 
Student copies (available only with a multiple user copy) £6 plus VAT resolution photos can be 
(UK and EU customers add VAT at 17.5% to “plus VAT” prices) used to enhance 

projects and 
presentations or to help 

MODULAR CIRCUIT DESIGN with training and 
educational material. 
Contains a range of tried and tested analogue and digital circuit modules, together with the They are royalty free for 
knowledge to use and interface them. Thus allowing anyone with a basic understanding of circuit symbols to use in commercial or 
design and build their own projects. Version 3 includes data and circuit modules for a range of popular PICs; includes personal printed projects, and can also be 
PICAXE circuits, the system which enables a PIC to be programmed without a programmer, and without removing it used royalty free in books, catalogues 
from the circuit. Shows where to obtain free software downloads to enable BASIC ies op lll magazine articles as well as worldwide web 
Essential information for anyone undertaking GCSE or “A” level electronics or technology and for hobbyists who want pages (subject to restrictions — see licence for 
to get to grips with project design. Over seventy different Input, Processor and Output modules are illustrated and fully full details) 
described, together with detailed information on construction, fault finding and components, including circuit symbols, Also contains a FREE 30-day evaluation of 
pinouts, power supplies, decoupling etc. Paint Shop Pro 6 — Paint Shop Pro image 
Single User £19.95 inc. VAT. Multiple User £34 plus VAT editing tips and on-line help included! 
(UK and EU customers add VAT at 17.5% to “plus VAT” prices) Price £19.95 inc. VAT 

Minimum system requirements for these CD-ROMs: Pentium PC, CD-ROM drive, 32MB RAM, 10MB hard disk space. Windows 95/98/NT/2000/ME/XP, mouse, sound card, web browser. 

“Please sendme: = CD-ROMORDERFORM ~~ ORDERING 

Electronic Projects 

Electronic Circuits & Components V2.0 

Analogue Electronics Version required: POSTAGE 
Filters Institutional 
Electronics CAD Pack Institutional 10 user 
Robotics & Mechatronics [_] Site licence 
Assembler for PiCmicro 

‘C’ for PICmicro 

Flowcode for PiCmicro 

Digital Works 3.0 








Digital Electronics V2.0 : Hobbyist/Student 

Student/Single User/Standard Version 
price includes postage to most 
countries in the world 
EU residents outside the UK add £5 for 
airmail postage per order 

PiCmicro Development Board (hardware) 
Development Board UK plugtop power supply 
Development Board 25-way connecting lead 

Teach-In 2000 + FREE BOOK 

Electronic Components Photos 

Electronics In Control — Single User | 

Electronics In Control — Multiple User Note: The software on each version is 
[] Modular Circuit Design — Single User the same, only the licence for use varies. 
[_] Modular Circuit Design — Multiple User 

PU IE ok sk oo es hh 9 eh A be wed bad OAS vO oe A 

Landaa pence pase oe ce ee es Post code: ................1@L NO: ... 2.2... eee ee eee 

NMI 6 ois ceenhe donde ee eso e es MeAwaeahieiyo5 seed ne ae co oead oy ee a ee eed os 
[-] | enclose cheque/PO in £ sterling payable to WIMBORNE PUBLISHING LTD for£ .............. 
[1] Please charge my Visa/Mastercard/Amex/Diners Club/Switch:£ ....... Card expiry date: ....... 

CG cae os he dela aa hare en awed entaes eed Gein fa cases Switch Issue No. ....... 


A 4 A A 


Our regular round-up of readers' own circuits. We pay between 
£10 and £50 for all material published, depending on length 
and technical merit. We're looking for novel applications and 

circuit designs, not simply mechanical, electrical or software . 
‘a, ideas. Ideas must be the reader's own work and must not WIN A PICO PC BASED 
sj) have been submitted for publication elsewhere. The OSCILLOSCOPE WORTH £586 

@ 100MS/s Dual Channel Storage Oscilloscope 
@ 50MHz Spectrum Analyser 

@ Multimeter @ Frequency Meter 

@ Signal Generator 

If you have a novel circuit idea which would be 
of use to other readers then a Pico Technology 
PC based oscilloscope could be yours. 

Every 12 months, Pico Technology will be 
awarding an ADC200-100 digital storage 
oscilloscope for the best IU submission. In 
addition, a DrDAQ Data Logger/Scope worth 

~ £69 will be presented to the runner aa 

circuits shown have NOT been proven by us. /ngenuity 
Unlimited is open to ALL abilities, but items for consideration in 
this column should be typed or word-processed, with a brief 
circuit description (between 100 and 500 words maximum) and 
full circuit diagram showing all relevant component values. 
Please draw all circuit schematics as clearly as possible. 
Send your circuit ideas to: Alan Winstanley, Ingenuity 
Unlimited, Wimborne Publishing Ltd., 408 Wimborne Road 
East, Ferndown Dorset BH22 9ND. (We do not accept sub- 
missions for /U via E-mail.) 

Your ideas could earn you some cash anda prize! — 

Switched Mode Fan 
Regulator — 4 Cooll Turm 

be circuit diagram shown in Fig.l was 
developed as a controller for a 12V 1A 
d.c. fan. It is a switched-type regulator which 
is more efficient than a linear type. A saw- 
tooth generator is derived from IC1, via the 
timing components resistor R1, capacitor C4 
and diodes D1 and D2. 

The waveform is fed to non-inverting input 
(pin 3) of IC2. This compares the difference 
between the sawtooth and a reference voltage 
produced by potentiometer VR1, and creates 
an output pulse that drives a MOSFET power 
transistor TR1. 

The remaining components including induc- 
tor L1 and diode D3 are used to create a 
smoothed d.c. voltage which powers the d.c. 
fan. Resistor R4 is a dummy load and by 
adjusting VR1, the duty cycle can be adjusted. 

555 Astable - Simpler Solution 

+5V TO +15V 


Fig.2. Circuit diagram for an alternative 555 Astable. 

Capacitors Cl to C3 decouple the supply, 
and note that electrolytic capacitors C6 to C8 
were placed in parallel to reduce their overall 
effective series resistance (ESR) together 
with any associated heating effects. 

Myo Min, 
Yangon, Myanmar. 

gustip of using the usual circuit set-up, if 
the charge/discharge current for the timing 
capacitor is taken from the output (pin 3) of 
the 555 timer i.c. then an astable multivibra- 
tor can be made using just three external 
components as shown in Fig.2. An alternative 
output can be taken from pin 7, the 
“discharge” pin, using it as an open collector 


output port, thus isolating the load from the 
RC timing network. Select the load R2 to suit. 
The mark: space ratio appears to be around 
3:2 but gets worse below 5V or so. With the 
values shown, the frequency range is around 
500Hz to 8kHz. 
P. Tomlinson, 
Hull, East Yorkshire. 

Fig.1. Circuit diagram for the Switched Mode Fan Regulator. 

Everyday Practical Electronics, September 2002 




LCOME to Net Work, our column written for Internet users. 
Regular users of our Internet site www.epemag.wimborne. can view the outline contents of each issue by visiting the 
Recent Issues page (/issues.htm) which features a photo or two of 
all our latest projects, with hyperlinks to pages describing the last 
four years or more of EPE projects as well. 

You can view or download indexes of previous volumes of EPE 
by visiting /idxpage.htm — the latest indexes are in PDF format. On 
the same index pages, any “Please Take Note” updates are also 
available on line. 

Frantic about FTP? 

It is worth reminding readers and newcomers that our FTP site hosts our free source codes 
for almost all our PICmicro projects and more besides. You can 
download source code using FTP software such as the freeware ver- 
sion of WS_FTP from, and all popular web 
browsers recognise FTP files as well. You may need a Zip utility 
such as WinZip (from to unzip some files; check for a huge range of programs, freeware and 
shareware. ‘ : 

Some readers do seem to struggle when trying to access the FTP 
site, resulting in a (sometimes hostile) email being delivered to the 
writer. There is more to the Internet than web pages! File Transfer 
Protocol is a universal way of managing the transfer of an array of 
files. The best online resource for help with FTP is www.ftp, which you should bookmark. 

From experience, the main reasons why problems arise are because: 

1. A commercial firewall is preventing FTP access. This often 
happens when trying to access the FTP site from a workplace. 
Readers report success when they try to access the site from home 

2. Folder View has been disabled in your web browser. In 
Microsoft Internet Explorer, go Tools/Internet Options/Advanced/ 
Browsing/Enable Folder view for FTP sites (tick yes). 

As a service for those with an aversion to FTP, Thomas Stratford 
maintains a web-style mirror site for our PICmicro source code at 

Broadband Thermometer 

The haphazardous rollout of broadband services across the UK 
continues in its usual lottery-like manner. British Telecom is 
focussing on ADSL (Asymmetric Digital Subscriber Line) for the 
masses, which provides a download speed over a phone line of up 
to ten times the speed of an ordinary 56kbps modem, with the added 
advantage that it can be “always on”. 

British Telecom states that ADSL now covers 66% of all house- 
holds. Cable or costly satellite or wireless access could be the only 
options for the remaining 34%. To help BT gauge the demand they 
have recently introduced a “pre-registration” facility on their web 
site ( I decided to head over there 
to take a look. 

I found a broadband availability checker, a pre-registration 
check, and a list of participating ISPs. The availability checker is a 
thermometer display indicating the level of interest in ADSL in 
your area. Unfortunately, for my own telephone exchange the ther- 
mometer is a worrying shade of ice blue. | 

A number of BT exchanges have been assigned a “trigger level” 
and in theory you can “pre-register” your interest in ADSL for that 
exchange. Then over time you can sit back and watch the virtual 
thermometer warm up and hit the roof, signifying that the exchange 
will finally be upgraded because the trigger level has been achieved 
(or not). | 


| alan @ 

“The size of your exchange indicates that ADSL may not be 
viable,” said the online form in my case. Unfortunately my 
exchange does not even have a trigger level allocated to it. Anyway, 
choosing a compatible ISP (let’s try BT Openworld for starters, I 
thought) to handle my registration had no effect on the “tempera- 
ture’; two weeks later there has been no contact from BT 
Openworld and the thermometer is still stuck firmly in the deep 
freezer department showing zero. 

The problem with the pre-registration scheme is that you can only 
register your interest through a participating ISP, who then passes it on 
to BT Wholesale. Evidently some ISP’s are not forwarding pre-regis- 
tration enquiries, which means that the registration figures and there- 
fore the levels of interest are going to be understated. 

LeechGet Your Files 

Seasoned web surfers know that right-clicking an image or file- 
name opens a pop-up menu allowing you to Save Target As... 
Internet Explorer 6 offers provides icons for saving, when your 
mouse pointer hovers over an image. Recently I came across a free 
utility program for Windows that enhances the file download 
process. LeechGet (fetch the English version from offers further right-click options in the pop-up 
menu, and the program allows you to split the download in any 
number of sections and download them in parallel. 

The main attraction is that by using the wizard you can see 
whether the server allows you to resume downloads following an 
interruption (e.g. your connection times out). There is no need to re- 
fetch the portions already downloaded. The download progress is 
also shown in the task bar area. This is an attractive and worthwhile 
program that has quickly become my standard means of fetching 
any files over a hundred kilobytes or so — download it now and see. 

Next month I'll take a look at ways you can grab entire web 
sites to save onto your hard disk. You can email me at 

| Broadband Availability Checker joxerediy 

: "Se We A eRe eS eA Re Ne SS i RY NM NR Sr A SPN RN Ee a ee WR eee 

| ( See ee ee ene 
Camigeckt Where can ! buy ic? : What to do next 5 

The pre-registration database shows that no trigger 
level has been calculated for your exchange. 

We are looking at allemative technologies and 
funding, to develop a way of bringing Broadband to 

Please register your interest in Broadband, so we 
define the most appropriate technology for your 

The barometer opposite shows the total number of 
registrations on your exchange. 

To register your interest in Broadband ADSL please 
contact your Service Provider or alternatively click 
Newt for a list of ISPs who may offer this pre- 
registration facility. 

Thank you for your interest. 

BT’s online Broadband Availability Checker is decidedly 
lukewarm at times. Stone cold in fact. 

Everyday Practical Electronics, September 2002 

Special Review 




Terry casts an appraising eye over two new products 


OR READERS who are not yet familiar with PIC devices, these 
are programmable integrated circuits. and comprise a family 
of microcontrollers from Arizona Microchip. 

A PIC is manufactured in an “empty” condition. Unlike con- 
ventional i.c.s which have some dedicated purpose, a PIC will 
only perform the task you have in mind if you program it within 
the limits set by the manufacturer’s parameters. It can then per- 
form a wide variety of jobs, replacing all manner of conventional 
i.c.s, and may be cost effective even when the circuit is fairly sim- 
ple. In more complex applications, a single PIC may replace a 
number of “ordinary” i.c.s. 

Many projects published in EPE are PIC-based. To construct 
these, readers may wish to program their own PIC or buy the ready- 
programmed device. However, for those wishing to develop their 
own PIC circuits, some means of programming them is clearly nec- 
essary. This work is done in two stages. First, the program is 
worked out (“written”) and any faults (“bugs”) removed from it. 
Second, it is “assembled” and transferred to the PIC. . 


If you are itching to see what a PIC can do for you, and have pos- 
sibly been put off by reading textbooks, then Flowcode could be a 
very good choice. This is a piece of computer software that teach- 
es you about PIC microcontrollers and shows how to program a 
“virtual” (make believe) device. 
Its great strength is that you need 
to know nothing about PIC pro- 
gramming theory! 

When you are ready to write 
your own programs, all you need 
is a Clear idea of what you want > 
the PIC to do. This is then 
entered on the screen in the form 
of a flow chart using standard 
flow chart symbols. It will then 
simulate the action of the PIC. 
You may play around to your 
heart’s content without touching 
a real PIC! This is as good as 
hand-on experience, but is faster 
and costs nothing (apart from the 
initial outlay). 


To use Flowcode, you will 
need (as a minimum require- 
ment) a PC with a Pentium 
processor and having a CD- 
ROM drive, 32MB of RAM and 
20MB of hard disk space. It 
is designed to be run under 

Everyday Practical Electronics, September 2002 

The Help Topics in Flowcode. 

Windows 98/ME/XP/NT/2000. It cannot be guaranteed to run 
using Windows 95. 

The software serves the purpose of developing the program 
while the associated PIC Development Board hardware may be 
used to transfer the program to a real PIC. Note that the 
Development Board may be used to program PICs from files not 
necessarily derived from Flowcode. 

For those who simply wish to learn about PICs and work on their 
own programs, the software may be used on its own. Users who 
would like to get their hands on a real PIC and make it work in a 
circuit will need both the hardware and software products. 


Users of these products will range from those having a fairly limit- 

_ ed knowledge to experts in conventional (pre-PIC) electronics. Some 

will only wish to gain an idea of what a PIC can do while others will 
want to write complex programs. Flowcode assumes that the user has 
sufficient existing electronics knowledge to use it effectively. 

Although not meant for the complete beginner, the necessary 
knowledge is easily gained from other sources. There are some 
inexpensive textbooks and useful pieces of software available. 

You will also néed some background knowledge regarding what 
PICs are and what they can do. You need to be reasonably com- 
puter-literate (if you can use the usual Windows operations such as 
cut, paste, print, save, etc. that will probably be sufficient). 

You should know the difference 
between analogue and digital sig- 
nals, be familiar with logic states 
and have some understanding of 
simple electronic components 
such as lL.e.d.s, switches, seven- 
segment displays, etc. 

It will probably be found easier 
working in a school or college 
environment where there is access 
to a teacher or lecturer. It may be 
harder for those working on their 
own. Even so, Flowcode’s interac- 
tive nature makes it ideal for home 
study and, after all, such users can 
work as slowly or as quickly as 
they need to. 


There are two elements to 
Flowcode — the program itself 
and the help topics. The latter 
may be opened separately or 
from within Flowcode. Here, 
there is an explanation of the 
subject matter (the “contents’’), 



also an alphabetical index and search facilities. These will be found 
useful at a later stage to locate a particular section. 

The subject matter begins with an introduction and “getting 
started” and ends with a list of some 28 practical tutorials. These 
are worked examples of flow charts that may be run on a “virtual” 
PIC to see how they behave. 

For someone having only a minimum amount of knowledge, it 
seems best to read through the first few topics briefly before doing 
anything else. This will check whether anything needs to be 
brushed up on before proceeding. 

The foundation work might seem daunting and it must be read 
slowly or the user might become discouraged. It would be best not to 
take too much notice of special terms initially because they might not 
be necessary to follow the first few tutorials. They may be 
looked at in more detail as they are needed. 

When the first few topics have been read, it would then 
be a good idea to look at the first tutorial or two and see 
how things work from a practical perspective. Back and 
forth reading from the help topics and from elsewhere goes 
in parallel with the tutorials. 

Lighting an LED (AQ) 

Clear Port A nea 

Light an LED (AQ} 
1-> PORT A 

2 eo nN @ hh BN a 


To use the tutorials from within the program you need to “open 
an existing Flowcode flowchart” whereupon a list of tutorials 
appears. Double-clicking on the first one (TUT_01) brings up the 
working screen with the first example on it (see Fig.1). At the top, 
there is a statement about what the PIC is going to do (in this case, 
Lighting an L.E.D.) and a flow chart complete with Begin, End and 
Output boxes appears. | 

The output boxes are defined in terms of what they do. There is 
(optionally) a pin diagram of the PIC (labelled with its type) and a 
row of four light-emitting diodes (1.e.d.s). 


Nothing happens until you click Run then Go/Continue (or press 
the “>” arrow on the toolbar). The program then runs and the 
appropriate l.e.d. “lights up” (goes red). The PIC diagram (if dis- 
played) also shows the pins that go high and low by turning from 
blank to red and blue respectively. 

By pressing “>” in the LED box, the connections between the 
l.e.d.s and the PIC may be displayed and edited and in properties, 
the l.e.d. colour may be changed to green, yellow or blue and the 
number of l.e.d.s in the group altered from one to eight. A complex 
program may be run step-by-step. The clock speed may also be var- 
ied and can be made as low as 1Hz to watch the effect at each stage. 

It is very rewarding to modify a tutorial by editing it, perhaps 
very gently to begin with and note the effect when the program is 
run. Double-clicking a flow chart box will bring up the properties 
which may then be changed (see Fig.2). Sorting out the reason if it 
fails to work as expected is highly instructive. 


When you feel confident, you will be able to create your own 
flow charts. When opening up a new window to do this, Begin and 
End boxes appear automatically because these are always needed. 
The flowchart is then built up by dragging icons from toolbars on 
to the diagram. 


There are icons for the various flow chart boxes and for input and 
output devices (such as switches and l.e.d.s). By dragging a box on 
to the flow chart, an arrow appears at the insertion point and the 
flow chart expands to include the new elements. 

A very powerful technique is to call macros into a flow chart. 
These are blocks of flow chart programming obtained from anoth- 
er flow chart and saved as a single icon. 

Flowcode operates by first translating the information from 
the flow chart into C language. It is then compiled and 
assembled using Arizona Microchip’s MPASM assembler 
(which is supplied on the CD-ROM) into an ASM file. However, 
all this goes on in the background without the user being aware 
of it. 

Lighting an LED (AO) 


f Clear Port A 
0-> PORT A 

f to nc o d TE 2 Sasaaeanuascononamade SS 


Fig.2. The editing prope 

| Fig.1 (left). The first Flowcode Tutorial, “Lighting an 
- i a 


The PIC Development Board is a piece of hardware that plugs 
into your computer parallel port (see photograph). To use it, you 
will need (as a minimum requirement) a PC having a 100MHz 
Pentium processor running Windows 98/ME/NT/2000/XP 
(again, it cannot be guaranteed to run in Windows 95). It should 
have a parallel printer port, 1MB of hard drive space and 16MB 
of RAM. 

The board is supplied in a case identical to a VHS cassette box 
together with software and documentation on a 3-5 in. floppy disk. 
The documentation is comprehensive and it might be best to print 
this out so that it is available for quick reference. 

The board receives the assembled file from the computer and 
programs the PIC which is plugged into it. This may be done sim- 
ply by clicking “compile to PIC” from the RUN menu in Flowcode. 
After that, the PIC may be run on the board. It may then be 
removed if need be and transferred to a custom-made p.c.b. 

Having designed electronic circuits for many years, the PIC 
Development Board certainly seems very nicely made and suffi- 
ciently robust for all normal purposes. The underside has a foam 
backing lightly stuck in place. This will protect the work surface 
from scratching, insulate it from any conducting objects and pre- 
vent fine copper tracks from becoming broken if it is placed on 
something sharp. 

This board is also compatible with the associated CD-ROMs 
Assembly for PICmicro V2 (formerly PICtutor), and “C” for 
PICmicro V2. 


Fitted with a 25-way D-type plug, the board connects via a stan- 
dard parallel lead to the computer parallel port. On top of the 
board, there are turned pin sockets for 8, 18, 28 and 40-pin PICs 
(most types are supported). A PIC16F84 is already fitted when sup- 
plied. This is electrically re-programmable and should provide up 
to 1,000 programming cycles. Replacements are widely available if 

Everyday Practical Electronics, September 2002 

The PIC Development Board and “VHS type” storage box. 

The board has a row of 13 1.e.d.s (to indicate the logic states when 
Port A/B pins are used as outputs) and pushbutton switches (to apply 
a logic state of 1 when they are used as inputs); a bank of four seven- 
segment l.e.d. indicators and a two-line 16-character liquid crystal dis- 
play (see photograph), with an associated contrast potentiometer. 
Also, there is a choice available between a crystal and on-board RC 
circuit (as set by a switch) to control the clock speed. 

Students often like to run things very slowly (say, at 1Hz) to see 
the effect of each step in the program (which was available in 
Flowcode during simulation). For this, the RC mode of operation is 
used. An on-board potentiometer may be used to alter the time 
period of the RC circuit and hence the clock speed, in conjunction 
with a “fast/slow” selector switch. | 

In addition, the board has a 40-way expansion bus suitable for an 
IDC cable link. There are also connectors for an audio output (for 
tone generation), for digital and analogue external sensors and port 
inputs/outputs. A manual Reset switch is also present. | 


While learning Flowcode, many users will rarely remove the exist- 
ing PIC from its socket. However, when programming PICs for use in 
your own circuits, if devices are inserted and removed too many times, 
this could cause excessive wear and tear to the socket. If you need to 
repeatedly remove and replace the PIC, you could use zero-insertion 
force (ZIF) sockets “piggy-back”’ style in the existing holders. 

For home use, the on-board sockets will probably be satisfacto- 
ry or you could use further standard turned-pin units inserted in the 
PIC sockets that are most used. This would be a cheaper alternative 
to using ZIF sockets. The new ones would then receive the wear 
and would be easily replaced. 

input from switches 



infinite Loop 
While 1 i 


Gat input from switches 0... 

Send switch data to the L... 

infinite Loop 

Using switches and the infinite loop. 

Everyday Practical Electronics, September 2002 

The board is said to be short-circuit proof on all 
inputs and outputs although this was not tested. A 
plug-in power supply unit is available although a suit- 
able 12V d.c. 500mA (minimum) unregulated unit 
may already be to hand. This is connected via a stan- 
dard “power-in” type socket. 

Although the supplied PIC16F84 has no analogue- 
to-digital converter, such devices are fully supported 
_and there is an on-board I.d.r. type light sensor and an 
“analogue sensor simulator” (potentiometer). Various 
external sensors such as for light, sound (micro- 
phone), temperature, pH, dissolved oxygen, gas pres- 
sure and heart rate are available as optional extras. 
These enable the programmed PIC to be used in “real 
life” situations. ; 
The capabilities of the PIC Development Board were 
tested by programming the as-supplied PIC using some 
of the Flowcode Tutorials. It performed the job perfect- 
ly. When “compile to PIC” is clicked on from within 
Flowcode, a box appears telling the user the stage that 
has been reached and whether or not the process has 
been successful. There is also a “program indicator” 
l.e.d. which operates during the time the PIC is being 
programmed. Programming is under full computer con- 
trol without manual intervention. 


As supplied, the PIC is ready-loaded with a test program. This 
checks for correct operation on delivery and takes the form of a sim- 
ple “Knight Rider” effect (flashing the l.e.d.s from left to right then 
back again). If this is successful, the board is working correctly. 

Some users will wish to study PICs for the needs of further 
education or industry. Others will want to work at home for self- 
interest and to develop their own programs. The materials are 
therefore made available in a student/home version; a single user 
institution version, a 10-user licence and a site licence. The 
student/home version does not have the burglar alarm and buggy 
simulations and this is reflected in the lower price. For many 
users, this will not matter. 

Flowcode is an excellent concept. Those using it can concentrate 
on simulating a practical task without having to learn complex pro- 
gramming techniques. This and the PIC Development Board will 
be of great interest to the independent hobbyist as well as those 
involved with education and industrial training. 

You can purchase Flowcode for PICmicro and the PIC 
Development Board from the EPE Electronics CD-ROMs pages in 
this issue — see page 677 for prices and ordering information. 


Technical support may be found at www.matrixmultimedia. The web site will contain Frequently Asked Questions, and 
any updates for Flowcode that may be available from time to time. 
Support is also available via email at: support@matrixmulti It is also available by phone (but not for the 
student/home version). | [ | 


Setup counter OSC4/OLKIN 
COUNT = 6 : OsezcLKoUT 

Cail Macro ; R67 
ShowDigit( COUNT, 0) RBS 


Tutorial operating a 7-segment display by using a macro. 


Special Feature 



A compendium of practical oscillator 
circuits for the creative experimenter, 
all based on inverting logic gates. 


MOS inverters can be usefully con- 
figured as oscillators. For sinewave 
generation it is usual to specify 
unbuffered inverters, whilst for other 
waveforms it may be more convenient to 
use the buffered kind. Many CMOS 
NAND and NOR gates can be connected 
so as to also behave as inverters, and thus 
as oscillators. 

The aim of this article is to explain how 
inverter oscillators work and to give some 
simple design pointers. 


_The essentials of a typical single-stage 
CMOS inverter are shown in Fig.1. The 
heart of the circuit is formed around the 
two series-connected enhancement mode 
MOSFETs, TR1 and TR2, p-channel and 
n-channel respectively. 

Fig.1. The essentials of a typical 
CMOS inverter, internal circuitry. 

The source (s) of TR1 is connected to 
the positive supply line (V_,). TR2’s 
source is connected to the earthy (OV) side 
of the supply. The two drains (d) are con- 
nected together, as are the two gates (g). 
The whole configuration forms a comple- 
mentary push-pull amplifier. 

When used with digital signals, a suffi- 
ciently large positive input voltage turns 
TR2 on and TR1 off. The output is then 
low. An input voltage close to OV takes the 


Part One 

output high. It is unsafe to take the input 
more negative than about —0-5V as this can 
lead to damage of the chip. 

At the input of this circuit is a protec- 
tive resistance, Rp (typically about 200 
ohms), and (usually) two gate protection 
diodes, D1 and D2. An excessive input 
voltage turns on one of the diodes and Rp 
then limits the current. There may also 
be two more protection diodes (D3 and 
D4) at the output. This stage, when used 
on its own, is known as an unbuffered 

~ inverter. 


In a buffered inverter, two more stages 
like this are added. The three-fold inver- 
sion gives the effect of a single inverter of 
much higher gain. The slope of the central 
portion of the input/output curve (Fig.2) is 
much steeper than a single inversion stage 
would produce. A digital input signal of 
high level makes the working point switch 
from P1 to P3, with a transition from P3 to 
P1 for a low level signal. 

There is a price to pay for this steeper 
operation. If a slowly changing input is 

Fig.2. Input/output voltage curve for 
the circuit in Fig.1. For oscillators, P2 
represents a typical working point. 
Ideally, output pulses should be as 
shown in waveform A, but when 
buffered inverters are used they can 
have jitter, as illustrated in waveform B. 

applied, a point may be reached where all 
three inversion stages are biased to work- 
ing points such as that at P2. The overall 
gain is then very high and stray feedback 
can make the circuit jitter or oscillate. 

Also, random voltage variations (noise) 
mixed up with the input can make the cir- 
cuit turn on and off rapidly, giving an out- 
put like that at waveform B instead of the 
wanted one at waveform A. 

This is why single-stage (unbuffered) 
inverters are preferred for sine wave oscil- 
lators, where the input is not a repetitive 
series of high/low pulses, but a smoothly 
changing waveform and where, in order to 
set up the inverter, it is biased to a working 
point in the region of P2. 


Diodes D1 and D2 are not meant to con- 
duct during normal operation. However, 
they may do so in oscillator circuits, with 
undesirable effects on the frequency. Fig.3 
shows a common square wave oscillator 
circuit configuration known by various 
names, such as astable, relaxation oscilla- 
tor and multivibrator. 

Fig.3. A two-inverter oscillator, show- 
ing the effect of Voc on f,, with and 
without swamping resistance Rp. Note 
that the frequency with Rp present is 
lower than the 50Hz obtained from the 
formula (see text). 

Everyday Practical Electronics, June 2002 

Graph curve A shows the effect on fre- 
quency of changing the supply voltage 
Vcc: Part of the change in frequency is the 
result of protection diode conduction. The 
effect can be reduced by connecting a large 
extra protection resistance R, in series 
with the input at Al. Curve B shows the 
change produced by increasing R, to 10 

The extent to which a swamping resis- 
tance like R, improves stability, or fre- 
quency accuracy, depends on how much 
bigger it is than the normal timing resis- 
tance, R,;. Note, however, that diode 
conduction is not the only influence on 
frequency stability. The output resis- 
tances of Al and A2, which are effective- 
ly in series with R, and C, respectively 
also affect timing, and they change with 

It is also necessary to be aware that 
increasing the value of R._ will reduce the 
oscillation frequency. This is due to the CR 
constant of this resistor in conjunction 
with the inverter’s input capacitance 
affecting the circuit’s principal time con- 
stant, determined by R, and C,. 

Frequency can be adjusted by changing 
C, or R,. This resistance also sets up the 
d.c. conditions; with C, disconnected (no 
oscillation) negative feedback from Al 
output to input via R, sets the working 
point to about that at P2 in Fig.2. 


A capacitor C charging from a d.c. volt- 
age source through a resistance R acquires 
a charge voltage which builds up, at first 
rapidly, and then ever more slowly as the 
charge accumulates. Theoretically, C takes 
for ever to charge right up to the source 
voltage. | 

However, the charge reaches 63 per cent 
of the source voltage after a time of Cx R 
seconds, known as the time constant CR, 
where C is in farads and R is in ohms. 
More conveniently, C can be in micro- 
farads and R in megohms. Thus a capaci- 
tor of 1“F charged through 1MQ becomes 
charged to 63 per cent of the applied volt- 
age after one second. 

In relaxation oscillators, such as that 
shown in Fig.3, the circuit changes state 
abruptly when the charge on C reaches the 
Al inverter’s critical threshold level, at 
about point P2 in Fig.2. At this point, the 
inverter whose output has been high 
switches to give a low output, and vice 

Capacitor C then discharges and when 
its voltage has decreased below the critical 
level, the circuit resets to its original state, 
and so on. If the charging and discharging 
threshold voltages are equal and the resis- 
tance is constant, the circuit generates rec- 
tangular waves with half cycles of equal 
duration, i.e. square waves. 

In Fig.3, the time constant CR is 0-01 
second (0-1MQ x 0-1uF). Consequently, 
the charge and discharge periods each take 
0-01 seconds, therefore one complete cycle 
takes 0-02 seconds. Using the period to 
frequency conversion formula f, = 1/2CR, 
the frequency is thus 1/(2 x 0-01) = 50Hz. 

It should be noted, though, that CR may 
also be affected by other stray R and C val- 
ues within the circuit. As stated earlier, it 
can also be affected by differences in sup- 
ply voltage, and by the value of Rp. 

However, as an approximation the formula 
can be used to determine the likely frequency 
to be produced. It can also be re-arranged so 
that for a given frequency, the required values 
for C and R can be calculated. 

Thus if R is known, to find the value of 
C required for frequency f,, the formula is 
rearranged to become: 

C= 1X2 x f, x R) 
To find R when C is known, it becomes: 
R= 1X2 xf, x C) . 

If the product RxC is megohms times 
microfarads the frequency is in Hertz. You 
can increase the units of R to 10M and cor- 
respondingly reduce those of C to 0-luF 
(100nF) and still get f, in Hz. In other words, 
if the units of R increase then those of C 
decrease by the same factor to get the same 
units of f,. You can get f, in kilohertz by hav- 
ing R in kilohms and C in microfarads or 
with R in megohms and C in nanofards. 

You should also be aware that the actual 
values for the components used as C and R 
are subject to manufacturing tolerances. To 
adjust the oscillator frequency to that actu- 
ally required, a variable resistor (i.e. poten- 
tiometer) can be inserted as in Fig.4. 

Fig.4. Frequency adjustment is provid- 
ed by VR1. The ratio of maximum to 
minimum frequency can exceed 10 in 
low-frequency oscillators where C and 
VA1 are large. Frequency adjustment 
has little effect on the mark-space 


We have assumed in the foregoing dis- 
cussion that the oscillator output is a 
Square wave whose peak-to-peak voltage 
is close to V.,. Because of differences 
between the MOSFETs manufactured into 
the CMOS inverter, the positive-going 
half-cycles may have slightly different 
durations to those of the negative-going 
half-cycles. They are said to have a differ- 
ent mark-space ratio. 

If necessary, the mark-space ratio can be 
equalised with the aid of an adjustment cir- 
cuit, such as that in Fig.5. In this case CR is 
calculated as C x (RI + (VRI/2)), although 
the presence of D1 and D2 will modify the 
ratio, typically reducing the frequency due 
to the charge/discharge voltage having been 
reduced by about 0-7V. 

A reasonable rule of thumb formula is 
shown in Fig.5. 

To provide a wide spread for the mark- 
space ratio, the value of R1 should be kept 
small in relation to the value of VR1. 

Standard CMOS inverters, such as the 
4069 hex inverter, can be used with Vac 

Everyday Practical Electronics, September 2002 

Fig.5. Mark-space adjustment is pro- 
vided by VR1. When D1 conducts the 
effective resistance is R1 plus section 
a of VR1. When D2 conducts it is R1 
plus VR1 section b. Thus the charge 
and discharge of C can be adjusted 
differentially. If a wide range of control 
is needed R1 can approach zero 
ohms. . : 

up to 15V (18V for some manufacturers). 
Modern high speed “equivalents”, such — 
as the 74HC04, are restricted to a maxi- 
mum V,, of 6V. They may also draw 
more current when biased for oscillator 


As illustrated in Fig.2, jitter can occur. 
when a “normal” inverter’s input voltage is 
at around the P2 level. To inhibit the jitter 
possible with slowly-changing inputs, 
CMOS inverters having a “snap” action, 
and known as Schmitt trigger inverters, 
can be used. 

With these a slowly rising input voltage 
has no effect until an upper critical (thresh- 
old) value is reached. Then the high output 
flips abruptly to the low condition. If the 
input is then reduced slightly the output 
remains low. 

Not until the input is lowered by a fair- 
ly substantial amount, to below the lower 
threshold level, does the output flip back to 
the high state. This backlash (hysteresis) 
prevents the output from jittering when 
there is noise mixed up with the input 
signal. - 

Schmitt trigger inverters can cope with 
signals arriving via long cables whose 
capacitance slows the rate of rise or fall of 

Fig.6. A Schmitt trigger inverter square 
wave oscillator which uses the mini- 
mum of components. 


a pulse and which may pick up noise or 

Buffered Schmitt devices such as the 
74HC14 hex inverter make good oscilla- 
tors whose output waveform is very close 
to a square wave (Fig.6). The slight differ- 
ence in the mark-space ratio which may be 
obtained is dependent upon the Schmitt 
trigger’s precise upper and lower threshold 

The only external components needed 
are a resistor and a capacitor. These act as 
a kind of integrator which turns the square 
wave at the output into a triangular wave at 
the input. This has a lower amplitude (typ- 
ically about 1V peak-to-peak for a 5V sup- 
_ ply) than the square wave and is too small 
to turn on the protection diodes, conse- 
quently no swamping resistance is needed. 

In a typical Schmitt inverter with V., = 
5V the circuit changes state when the input 
voltage rises to about +3V or falls to about 
+2V. Since the d.c. average voltage on C is 
2:5V (V¢,/2) changes in input voltage of 
0-5V are all that is needed to flip the circuit 
from one state to the other. 

The difference between the two critical 
threshold voltages is called the hysteresis 
voltage. For the 74HC14 inverter this is 
eae quoted on data sheets as 0-5V for 

= 2V, 0-8V for Vig = 4-:5V and 0-95V 
fee = 6). 

Oscillation frequency is determined by 
how long it takes for these changes of input 
voltage to occur after a switch of output 
from high to low, or low to high. Since the 
required changes are only around one fifth 
of Vic the time to produce them is rela- 
tively smaller than with the oscillators dis- 
cussed so far. 

The result is that the frequency is much 
higher than might be expected from the 
basic RC time constant. It is roughly 2/RC, 
but this is only an approximation since it 1s 
also affected by the supply voltage and the 
resulting hysteresis thresholds. 

The triangle waveform at the junction of 
C and R can be tapped by using an op.amp 
buffer, as shown in the dotted box of Fig.6. 

It is also possible to vary the mark-space 
ratio of the oscillator by using the diode 
and potentiometer configuration shown in 
Fig.5. This also has the effect of changing 

the triangle waveform to a rising or falling — 

ramp (sawtooth). 


Another method of yielding sawtooth 
and pulse waveforms is shown in Fig.7, in 
which C is discharged via transistor TR1 as 
soon as the output of A2 goes high. The 

Fig.7. Sawtooth oscillator created by 
rapidly discharging C via TR1. 


discharge of C causes the output of A2 to_ 

go low again, turning off TR1, whereupon 
C starts to charge up again and the process 
is repeated. 

The discharge of C is very rapid and, 
almost immediate, but during the discharge 
of C there is a very short negative-going 
pulse at Al output and a corresponding 
positive-going pulse at A2 output. The 
waveform at C is effectively a rising ramp. 


The sawtooth amplitude is about V,,/2 
and the rising of its slope is not linear. 
Linearity can be improved by substituting a 
constant current source for R. This can be 
made easier by taking advantage of the fact 
that the circuit still works if the top end of 
R is connected to +V(, instead of Al out- 
put, as shown in Fig.8. 

Fig.8. Linearising a sawtooth waveform. 

There is, however, another problem. The 
frequency of the sawtooth is only about 
half that of the original triangular wave. 
The frequency can be increased by pre- 
venting C from discharging completely 
through TRI. With less recharging to be 
done the cycle speeds up. 

In Fig.8 the speeding up is done by con- 
necting two diodes in the emitter (e) of 
TR1. These make TR1 turn off before C is 
fully discharged. The inclusion of resistor 
Rx (of 1kQ, say) prevents damaging cur- 
rent flow from A2 output through the base- 
emitter path of TR1. 

With V.¢ at +5V the sawtooth frequen- 
cy will typically be about the same as the 
original triangle wave frequency and the 
two amplitudes will also be similar. 
Linearity is improved, too. 


Oscillators can usually be considered as 
amplifiers with positive feedback. The 
feedback increases gain and if there is 
enough of it, the gain becomes infinite. 
Then any noise at the input is amplified by 
as much as the circuit will allow. In prac- 
tice this means that the amplitude builds up 
until the system overloads. This reduces 
gain and stops any further increase. 

In a sine wave oscillator, the positive 
feedback is channeled from output to 
input through some sort of filter which 
permits the greatest feedback at one par- 
ticular frequency. This is the oscillation 


Since, in an inverter, a positive input 
voltage results in a negative output volt- 
age an inverter should not oscillate if 
feedback is taken directly from output to 
input. Such feedback is negative and 
reduces gain. 

Most CMOS sine wave oscillators do 
incorporate feedback from output to input, 
but only at d.c. The feedback’s job is to set 
the working point on the linear part of the 
input/output curve and so establish the 
right starting conditions. 

To permit a.c. oscillation, some arrange- 
ment must be incorporated to create a 
second phase reversal at the oscillation fre- 
quency. The two successive inversions 
(positive to negative, negative to positive) 
make feedback positive at the oscillation 

One way of providing a second phase 
inversion is to pass signals through a sec- 
ond inverter (but note that this will not 
work with Schmitt inverters). This entails a 
risk, though: if feedback occurs at d.c. the 
working point may be de-stabilised. The 
result (latchup) leaves all the inverters 
either hard on or hard off (high or low), 
preventing a.c. oscillation. Also, if the 
overall feedback is over a wide band of fre- 
quencies, the circuit may oscillate at an 
unintended frequency. 

Ways of avoiding these dangers will be 
covered later. For the present, let’s look at 
other methods of obtaining a second phase 

One method is to use a transformer. If 
the inverter output is applied’ to a primary 
winding, the secondary winding yields a 
copy, scaled up or down in voltage accord- 
ing to the turns ratio. The secondary 
winding is electrically isolated from the 

To make an oscillator, we choose the end 
of the transformer secondary winding 
which provides a voltage having the 
opposite polarity to the inverter’s output 
voltage. This gives the required second 


A practical version, shown in Fig.9, 
incorporates a feedback adjuster, VR1, 
which can be set to control the strength of 
oscillation. In general, a setting which is 
just sufficient to ensure reliable oscillation 
gives the best waveform. — 

Fig.9 Using a transformer to produce 
phase inversion. 

Everyday Practical Electronics, September 2002 

The frequency is determined by capaci- 
tor Cl and winding L,. Capacitor C2 
merely provides a bypass (decoupling) 
capacitance, and its presence ensures that 
there is d.c. negative feedback to stabilize 
the operating conditions. 

A pure sine wave appears across L/C1. 
A distorted (peaks flattened) waveform 
appears at the inverter output but it can be 
made almost sinusoidal by careful setting 
of VR1. 

The turns ratio depends on both the 
transconductance (g) of the inverter and 
the dynamic resistance (R,) of the LC 
combination. The effect of the trans- 
former is to reduce the impedance seen 
looking into the coupling winding from 
the inverter output to R,/N’, where N is 
the ratio of the turns on L. to the turns on 
the coupling winding. 

To design an oscillator, first assume 
VRI1 = O then calculate the turns ratio 
which will just allow oscillation. For this 
N = (g x R,). In this type of oscillator, 
the working point will be on the linear 
part of the characteristic, i.e. P2. Both 
f.e.t.s are on and g is the sum of their 

To take an example, if g = 3ms and R, = 
100k, N is 3/1000 x 100,000 = 300. To 
allow for adjustment and device spreads a 
lower turns ratio is chosen. The best value 
of VR1 is best found by experiment but is 
usually a few times the output resistance of 
the inverter; try a 100k preset. 

The correct setting of VR1 should give 
reliable oscillation in the face of any likely 
supply-voltage variations. When set up 
correctly the level of signal at the input is 
low enough to ensure that the protection 
diodes never conduct. Hence R, is not 
needed. This is important when frequency 
stability must be maximised because both 
R. and input capacitance are temperature- 


In any oscillator the amplitude in- 
creases until something stops it. In CMOS 

oscillators the limiting mechanism is peak 
flattening as the signals become large 
enough to be affected by the nonlinearity 
of the transfer characteristic. If VR1 is low 
enough to allow strong oscillation the out- 
put approaches a square wave. 

Fig.10 Colpitts oscillator. Phase inver- 
sion at the oscillating frequency is 
created by the pi-network C1, L, C2. 

If VR1 is set for “just oscillating” the 
output is a sine wave except for slight peak 
crushing. The waveform across the LC 
itself can still be a good sinewave even 
when the output is crushed because the 
harmonics produced by crushing are atten- 
uated by the LC circuit. With symmetrical 
crushing the main harmonic is the third and 
this is well away from the peak of the LC 
resonance curve. 

When VR1 is set for strong oscillation 
the peak-to-peak output approaches V_<. 
The level across the LC is normally much 
lower. The signal across the coupling 
winding is a good sine wave but only one 
Nth of the amplitude at the LC. To extract 
the full LC signal without upsetting circuit 
operation calls for a buffer, such as the 
f.e.t. follower in Fig.9. 


Transformers are often inconvenient. 
Designers may prefer to use a simple 
inductor without a secondary winding or 

tappings. In this case the required second 
inversion can be performed by the tuning 
components themselves. 

In the usual arrangement shown in 
Fig.10, the two capacitances C1 and C2, 
together with inductance L, form a pi-net- 
work. This inverts the voltage at one spe- 
cific frequency, that at which the reactance 
of L is the same as the reactance of Cl and 
C2 in series. 

Oscillation may well be violent and the 
waveform poorly shaped. Adding a feed- 
back-control resistance, VR1, provides a 
“throttle” control to adjust the oscillation 
level. Then the waveform at the inverter 
output is peak-clipped but good sine waves 
are obtainable across the capacitors. 
Because of the network phase inversion, 
waveform voltages V1 and V2 are in 
antiphase. If C1 = C2 (the usual case), the 
amplitudes of V1 and V2 are equal, but 

This oscillator is a version of a classical 
one, the Colpitts oscillator. It is easy to get: 
it oscillating. The requirement is that the 
inverter should produce a gain of over one 
when driving the impedance looking into 
the pi-network. 

With Cl = C2, this impedance is a quar- 
ter of the dynamic resistance of the tuning 
circuit at the oscillation frequency. In most 
practical cases, this impedance is more 
than high enough and VRI1 is needed to 
limit amplitude and ensure good wave- 
forms. The value of VR1 is not critical. 
Even if the resistance is considerably less 
than the maximum possible, the wave- 
forms can still be good. 

At radio frequencies, the Colpitts circuit 
can be tuned by a two-gang variable capac- 
itor in place of Cl and C2, with the rotor 
earthed. A tuning range (ratio of maximum 
to minimum frequency) in excess of three 
is usually obtainable. The range is limited 
by the practical ve ie available, 
where f/f; = about V10 
in a circuit with pict stray capacitance. 

To be concluded next month. 


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Everyday Practical Electronics, September 2002 



ist Compendium 
000 CD-ROM 

2000 CD-ROM 

The whole of the 12-part Teach-/n 2000 series by John 
Becker (published in EPE Nov ’99 to Oct 2000) is now 
available on CD-ROM. Plus the Teach-/n 2000 interac- 
tive software covering all aspects of the series and 
Alan Winstanley’s Basic Soldering Guide (including 
illustrations and Desoldering). 

Teach-In 2000 covers all the basic principles of elec- 
tronics from Ohm’s Law to Displays, including Op.Amps, 
Logic Gates etc. Each part has its own section on the inter- 
active software where you can also change component 
values in the various on-screen demonstration circuits. 

The series gives a hands-on approach to electronics 
with numerous breadboard circuits to try out, plus a sim- 
ple computer interface which allows a PC to be used as 
a basic oscilloscope. 

ONLY £12.45 including VAT and p&p 
'O]cel=)meorele(- mi t-t-[e1gt) (am e1Bl51@)\), | 


Circuits and Design 


Owen Bishop 

Provides a wealth of circuits and circuit modules for use in 
remote control systems of all kinds; ultrasonic, infra-red, 
optical fibre, cable and radio. There are instructions for 
building fourteen novel and practical remote control pro- 
jects. But this is not all, as each of these projects provides 
a model for building dozens of other related circuits by sim- 
ply modifying parts of the design slightly to suit your own 
requirements. This book tells you how. 

Also included are techniques for connecting a PC toa 
remote control system, the use of a microcontroller in 
remote control, as exemplified by the BASIC Stamp, and 
the application of ready-made type-approved 418MHz 
radio transmitter and receiver modules to remote control 

160 pages "6.49 
systems. . 

M. P. Horsey 

This book offers a wide range of tested circuit modules which 
can be used as electronics projects, part of an electronics 
course, or as a hands-on way of getting better acquainted with 
Electronics Workbench. With circuits ranging from ‘bulbs and 
batteries’ to complex systems using integrated circuits, the 
projects will appeal to novices, students and practitioners 

Electronics Workbench is a highly versatile computer simu- 
lation package which enables the user to design, test and 
modify their circuits before building them, and to plan PCB lay- 
outs on-screen. All the circuits in the book are provided as 
runnable Electronic Workbench files on the enclosed CD- 
ROM, and a selection of 15 representative circuits can be 

_ explored using the free demo version of the application. 

Computing & Robotics 


N. Kantaris and P. R. M. Oliver 

If you want to know what to do next when confronted with 
Microsoft's Windows XP screen, then this book is for you. It 
applies to both the Professional and Home editions. 

The book was written with the non-expert, busy person in 
mind. It explains what hardware requirements you need in 
order to run Windows XP successfully, and gives an 
overview of the Windows XP environment. ° 

The book explains: How to manipulate Windows, and how to 
use the Control Panel to add or change your printer, and con- 
trol your display; How to control information using WordPad, 
Notepad and Paint, and how to use the Clipboard facility to 
transfer information between Windows applications; How to 
be in control of your filing system using Windows Explorer 
and My Computer; How to control printers, fonts, characters, 
multimedia and images, and how to add hardware and soft- 
ware to your system; How to configure your system to com- 
municate with the outside world, and use Outlook Express 
for all your email requirements; How to use the Windows 
Media Player 8 to play your CDs, burn CDs with your 
favourite tracks, use the Radio Tuner, transfer your videos to 
your PC, and how to use the Sound Recorder and Movie 
Maker; How to use the System Tools to restore your system 
to a previously working state, using Microsoft's Website to 
update your Windows set-up, how to clean up, defragment 
and scan your hard disk, and how to backup and restore your 
data; How to successfully transfer text from those old but 
cherished MS-DOS programs. 

Order code BP514 £7.99 

Robert Penfold 
Shows the reader how to build a variety of increasingly 
sophisticated computer controlled robots using the bril- 
liant Lego Mindstorms Robotic Invention System (RIS). 
Initially covers fundamental building techniques and 
mechanics needed to construct strong and efficient 
robots using the various “click-together” components 
supplied in the basic RIS kit. Explains in simple terms 
~ how the “brain” of the robot may be programmed on 
screen using a PC and “zapped” to the robot over an 
infra-red link. Also, shows how a more sophisticated 
Windows programming language such as Visual BASIC 
may be used to control the robots. 

Detailed building and programming instructions pro- 
vided, including numerous step-by-step photographs. 

268 pages 

288 pages — large format ielxelimerelel-M=lsclthie £14.99 

MINDSTORMS -— Robert Penfold 

Covers the Vision Command System 

Shows the reader how to extend the capabilities of the 
brilliant Lego Mindstorms Robotic Invention System 

(RIS) by using Lego’s own accessories and some simple . 

home constructed units. You will be able to build robots 
that can provide you with ‘waiter service’ when you clap 
your hands, perform tricks, ‘see’ and avoid objects by 
using ‘bats radar’, or accurately follow a line marked on 


the floor. Learn to use additional types of sensors includ- 
ing rotation, light, temperature, sound and ultrasonic and 
also explore the possibilities provided by using an addi- 
tional (third) motor. For the less experienced, RCX code 
programs accompany most of the featured robots. 
However, the more adventurous reader is also shown 
how to write programs using Microsoft’s VisualBASIC 
running with the ActiveX control (Spirit-OCX) that is pro- 
vided with the RIS kit. 

Detailed building instructions are provided for the fea- 
tured robots, including numerous step-by-step pho- 
tographs. The designs include rover vehicles, a virtual 
pet, a robot arm, an ‘intelligent’ sweet dispenser and a 
colour conscious robot that will try to grab objects of a 

specific colour. 
(OT fol-) merele(-M =] atc] 074 £14.99 


Discover the’ potential of the PIC’ micro- 
controller through graded projects — this book could 
revolutionise your electronics construction work! 

A uniquely concise and practical guide to getting up 
and running with the PIC Microcontroller. The PIC is 
one of the most popular of the microcontrollers that are 
transforming electronic project work and product 

Assuming no prior knowledge of microcontrollers and 
introducing the PICs capabilities through simple projects, 
this book is ideal for use in schools and colleges. It is the 
ideal introduction for students, teachers, technicians and 
electronics enthusiasts. The step-by-step explanations 
make it ideal for self-study too: this is not a reference book 
— you start work with the PIC straight away. 

The revised second edition covers the popular repro- 
grammable EEPROM PICs: P16C84/16F84 as well as 
the P54 and P71 families. 

Oy ce (=)arerele(=m\\| atic) £13.99 


John Crisp 

lf you are, or soon will be, involved in the use of 
microprocessors, this practical introduction is essential 
reading. This book provides a thoroughly readable intro- 
duction to microprocessors. assuming no previous 
knowledge of the subject, nor a technical or mathemat- 
ical background. It is suitable for students, technicians, 
engineers and hobbyists, and covers the full range of 
modern microprocessors. 

After a thorough introduction to the subject, ideas are 
developed progressively in a well-structured format. All 
technical terms are carefully introduced and subjects 
which have proved difficult, for example 2’s comple- 
ment, are clearly explained. John Crisp covers the com- 
plete range of microprocessors from the popular 4-bit 
and 8-bit designs to today’s super-fast 32-bit and 64-bit 
versions that power PCs and engine management 

systems etc. : 
Ol ce[(=\mrecele(- | =e ; £18.99 

298 pages 

270 pages 

222 pages 

_240 pages 

Contents: Some basic concepts; Projects with switches, 
LEDs, relays and diodes; Transistors; Power supplies; Op.amp 
projects; Further op.amp circuits; Logic gates; Real logic cir- 
cuits; Logic gate multivibrators; The 555 timer; Flip-flops, 
counters and shift registers; Adders, comparators and multi- 
plexers; Field effect transistors; Thyristors, triacs and diacs; 
Constructing your circuit; Index. 

227 pages Temporarily out of print 


W. D. Phillips 

This is a whole book about designing and making elec- 
tronic clocks. You start by connecting HIGH and LOW logic 
signals to logic gates. You find out about and then build and 
test bistables, crystal-controlled astables, counters, 
decoders and displays. All of these subsystems are 
carefully explained, with practical work supported 
by easy to follow prototype board layouts. 

Full constructional details, including circuit diagrams and 
a printed circuit board pattern, are given for a digital 
electronic clock. The circuit for the First Clock is modified 
and developed to produce additional designs which include 
a Big Digit Clock, Binary Clock, Linear Clock, Andrew’s 
Clock (with a semi-analogue display), and a Circles Clock. 
All of these designs are unusual and distinctive. 

This is an ideal resource for project work in GCSE 
Design and Technology: Electronics Product, and for 
project work in AS-Level and A-Level Electronics and 

194 pages, A4 spiral bound [elgel-jgiereye(-me) eam £17.50 

A. L. Brown 
This book shows you how, with common sense and 
basic do-it-yourself skills, you can protect your home. It 
also gives tips and ideas which will help you to maintain 
and improve your home security, even if you already 
have an alarm. Every circuit in this book is clearly 
described and illustrated, and contains components that 
are easy to source. Advice and guidance are based on 
the real experience of the author who is an alarm 
installer, and the designs themselves have been rigor- 
ously put to use on some of the most crime-ridden 
streets in the world. 

The designs include all elements, including sensors, 
-detectors, alarms, controls, lights, video and door entry 
systems. Chapters cover installation, testing, maintenance 

and upgrading. 


Mike James 

The practical solutions to real problems shown in this cook- 
book provide the basis to make PIC and 8051 devices real- 
ly work. Capabilities of the variants are examined, and ways 
to enhance these are shown. A survey of common interface 
devices, and a description of programming models, lead on 
to a section on development techniques. The cookbook 
offers an introduction that will allow any user, novice or expe- 
rienced, to make the most of microcontrollers. 

Order code NE26 £21.99 


R. A. Penfold 

This book first covers the basics of simple logic circuits in 
general, and then progresses to specific TTL logic inte- 
grated circuits. The devices covered include gates, oscilla- 
tors, timers, flip/flops, dividers, and decoder circuits. Some 
practical circuits are used to illustrate the use of TTL 
devices in the “real world”. 

O}ce(=\areiele(- =] ey £5.45 

F. A. Wilson, C.G.1.A., C.Eng., F.1.E.E., F.1.E.R.E., F.B.1.M. 
Bridges the gap between complicated technical theory, 
and “cut-and-tried” methods which may bring success in 
design but leave the experimenter unfulfilled. A strong 
practical bias — tedious and higher mathematics have been 
avoided where possible and many tables have been 

The book is divided into six basic sections: Units and 
Constants, Direct-Current Circuits, Passive Components, 
Alternating-Current Circuits, Networks and Theorems, 

Ol ce(-]aerele (= =] da}; £5.49 

192 pages 

142 pages 

256 pages 

yN | ie nd gd (ot 


Everyday Practical Electronics, September 2002 

Bebop To The Boolean Boogie 

By Clive (call me Max) Maxfield 
Specially imported by EPE — 
Excellent value 

An Unconventional Guide to Electronics 
Fundamentals, Components and Processes 



This book gives the “big picture” of digital 
electronics. This indepth, highly readable, up- 
to-the-minute guide shows you how electronic 
devices work and how they’re made. You'll dis- 
cover how transistors operate, how printed cir- 
cuit boards are fabricated, and what the 
innards of memory ICs look like. You'll also 
gain a working knowledge of Boolean Algebra : _ 
and Karnaugh Maps, and understand what Reed- tutler logic is and how 
it’s used. And there’s much, MUCH more vncmaing a recipe for a truly 
great seafood gumbo!). 

Hundreds of carefully drawn illustrations clearly show the important points 
of each topic. The author’s tongue-in-cheek British humor makes it a delight 
to read, but this is a REAL technical book, extremely detailed and accurate. A 
great reference for your own shelf, and also an ideal gift for a friend or family 
~ member who wants to understand what it is you do all day. .. . 

470 pages — large format 

Beboputer Computer Simulator) 

Clive (Max) Maxfield and Alvin Brown 

This follow-on to Bebop to the Boolean Boogie 
is a multimedia extravaganza of information 
about how computers work. It picks up 
where “Bebop |” left off, guiding you through 

the fascinating world of computer design . . 

.and you'll have a few chuckles, if not belly 

laughs, along the way. In addition to over 

200 megabytes of mega-cool multimedia, 

the CD-ROM contains a virtual microcom- 
puter, simulating the motherboard and stan- 
dard computer peripherals in an extremely real- 
istic manner. In addition to a wealth of technical 
information, myriad nuggets of trivia, and hundreds of 

carefully drawn illustrations, the CD-ROM contains a set of lab experiments 
for the virtual microcomputer that let you recreate the experiences of early 
computer pioneers. If you're the slightest bit interested in the inner workings 
of computers, then don’t dare to miss this! 

Over 800 pages in Adobe Acrobat format £21.95 


With FREE Software: Number One Systems — EASY-PC 
Professional XM and Pulsar (Limited Functionality) 
Richard Monk 

Covers binary arithmetic, Boolean algebra and logic gates, combination logic, 
sequential logic including the design and construction of asynchronous and 
synchronous circuits and register circuits. Together with a considerable prac- 
tical content plus the additional attraction of its close association with 
computer-aided design including the FREE software. 

There is a ‘blow-by-blow’ guide to the use of EASY-PC Professional XM (a 
schematic drawing and printed circuit board design computer package). The 
guide also conducts the reader through logic circuit simulation using Pulsar 
software. Chapters on p.c.b. physics and p.c.b. production techniques make 
the book unique, and with its host of project ideas make it an ideal companion 
for the integrative assignment and common skills components required by 
BTEC and the key skills demanded by GNVQ. The principal aim of the book 
is to provide a straightforward approach to the understanding of digital 

Those who prefer the ‘Teach-In’ approach or would rather experiment with 
some simple circuits should find the book’s final chapters on printed circuit 
board production and project ideas especially useful. 

ici i ae 

Testing, Theory ame! Reiieremce 



lan R. Sinclair 

This book, intended for enthusiasts, students and technicians, seeks to estab- 
lish a firm foundation in digital electronics by treating the topics of gates and 
flip-flops thoroughly and from the beginning. 

Topics such as Boolean algebra and Karnaugh mapping are explainend, 
demonstrated and used extensively, and more attention is paid to the subject 
of synchronous counters than to the simple but less important ripple counters. 

No background other than a basic knowledge of electronics is assumed, 
and the more theoretical topics are explained from the beginning, as also are 
many working practices. The book concludes with an explanation of micro- 
processor techniques as applied to digital logic. 

200 pages ta 

By Clive “Max” Maxfield and Kuhoo Goyal Edson 

EDA; which stands for electronic design automation, refers to the software 
tools (computer programs) used to design electronic products. EDA actually 
encompasses a tremendous variety of tools and concepts. The aim of this 
book is to take a 30,000-foot view of the EDA world. To paint a “big picture” 
that introduces some of the most important EDA tools and describes how they 
are used to create integrated circuits, circuit boards and electronic systems. 
To show you how everything fits together without making you want to bang 
your head against the nearest wall. 

“Did you ever wonder how the circuit boards and silicon chips inside your 
personal computer or cell phone were designed? This book walks you 
through the process of designing a city on an alien planet and compares it to 
designing an electronic system. The result is a fun, light-hearted and enter- 
taining way to learn about one of the most important — and least understood 
— industries on this planet.” 

John Barr, Managing Director, Robertson Stephens 

98 pages — Large format £29.95 

Owen Bishop 
Owen Bishop has produced a concise, readable text to introduce a wide range 
of students, technicians and professionals to an important area of electronics. 
Control is a highly mathematical subject, but here maths is kept to a minimum, 
with flow charts to illustrate principles and techniques instead of equations. 
Cutting edge topics such as microcontrollers, neural networks and fuzzy 
control are all here, making this an ideal refresher course for those working in 
Industry. Basic principles, control algorithms and hardwired control systems 
are also fully covered so the resulting book is a comprehensive text and well 
suited to college courses or background reading for university students. 
The text is supported by questions under the headings Keeping Up and Test 
Your Knowledge so that the reader can develop a sound understanding and 
the ability to apply the techniques they are learning. 

228 pages £17.99 

Robert Goodman 

You never again have to be flummoxed, flustered or taken for a ride by a 
piece of electronics equipment. With this fully illustrated, simple-to-use guide, 
you will get a grasp on the workings of the electronic world that surrounds you 
— and even learn to make your own repairs. 

You don’t need any technical experience. This book gives you: Clear expla- 
nations of how things work, written in everyday language. Easy-to-follow, illus- 
trated instructions on using test equipment to diagnose problems. Guidelines 
to help you decide for or against professional repair. Tips on protecting your 
expensive equipment from lightning and other electrical damage. Lubrication 
and maintenance suggestions. 

Covers: colour TVs, VCRs, radios, PCs, CD players, printers, telephones, 
monitors, camcorders, satellite dishes, and much more! 

394 pages £21.99 

The books listed have been selected by Everyday Practical 
Electonics editorial staff as being of special interest to every- 
one involved in electronics and computing. They are supplied 
by mail order direct to your door. Full ordering details are 
given on the last book page. 


All prices include UK postage 

Audio ama Music 

R. A. Penfold 
This book provides circuits and background information for a 
range of preamplifiers, plus tone controls, filters, mixers, etc. 
The use of modern low noise operational amplifiers and a spe- 
cialist high performance audio preamplifier i.c. results in cir- 
cuits that have excellent performance, but which are still quite 
simple. All the circuits featured can be built at quite low cost 
(just a few pounds in most cases). The preamplifier circuits 
featured include: Microphone preamplifiers (low impedance, 
high impedance, and crystal). Magnetic cartridge pick-up pre- 
amplifiers with R.1.A.A. equalisation. Crystal/ceramic pick-up 
preamplifier. Guitar pick-up preamplifier. Tape head preamplifi- 
er (for use with compact cassette systems). 

Other circuits include: Audio limiter to prevent overload- 
ing of power amplifiers. Passive tone controls. Active tone 
controls. PA filters (highpass and lowpass). Scratch and 

rumble filters. Loudness filter. Mixers. Volume and balance 

@] ce(-)morele(-M =] oni 0)s) £4.49 

92 pages 



R. A. Penfold 

Whether you wish to save money, boldly go where no 
musician has gone before, rekindle the pioneering spirit, or 
simply have fun building some electronic music gadgets, the 
designs featured in this book should suit your needs. The 
projects are all easy to build, and some are so simple that 
even complete beginners at electronic project construction 
can tackle them with ease. Stripboard layouts are provided 
for every project, together with a wiring diagram. The 

Everyday Practical Electronics, September 2002 

mechanical side of construction has largely been left to the 
individual constructors to sort out, simply because the vast 
majority of project builders prefer to do their own thing. 

None of the designs requires the use of any test 
equipment in order to get them set up properly. Where 
any setting up is required, the procedures are very 
straightforward, and they are described in detail. 

Projects covered: Simple MIIDI tester, Message grab- 
ber, Byte grabber, THRU box, MIDI auto switcher, 
Auto/manual switcher, Manual switcher, MIDI patchbay, 
MIDI controlled switcher, MIDI lead tester, Program 
change pedal, Improved program change pedal, Basic 
mixer, Stereo mixer, Electronic swell pedal, Metronome, 
Analogue echo unit. 


138 pages 

Data and 



Owen Bishop 

This book deals with the subject in a non-mathematical 
way. It reviews the main types of filter, explaining in sim- 
ple terms how each type works and how it is used. 

The book also presents a dozen filter-based projects 
with applications in and around the home or in the 
constructor’s workshop. These include a number of audio 
projects such as a rythm sequencer and a multi-voiced 
electronic organ. 

Concluding the book is a practical step-by-step guide to 
designing simple filters for a wide range of purposes, with 
circuit diagrams and worked examples. 

'@] vo (=) mrevele(-M =] 4e)5) £5.49 


With FREE Software: Number One efelmali7 iis 
Systems — EASY-PC 

Professional XM and Pulsar (Limited Functionality) 
Richard Monk 

Covers binary arithmetic, Boolean algebra and logic 
gates, combination logic, sequential logic including the 
design and construction of asynchronous and synchro- 
nous circuits and register circuits. Together with a consid- 
erable practical content plus the additional attraction of its 
close association with computer aided design including 
the FREE software. 

There is a ‘blow-by-blow’ guide to the use of EASY-PC 
Professional XM (a schematic drawing and printed circuit 
board design computer package). The guide also con- 
ducts the reader through logic circuit simulation using 
Pulsar software. Chapters on p.c.b. physics and p.c.b. 
production techniques make the book unique, and with its 
host of project ideas make it an ideal companion for the 
integrative assignment and common skills components 
required by BTEC and the key skills demanded by GNVQ. 
The principal aim of the book is to provide a straightfor- 
ward approach to the understanding of digital electronics. 

Those who prefer the ‘Teach-In’ approach or would 
rather experiment with some simple circuits should find 
the book’s final chapters on printed circuit board produc- 
tion and project ideas especially useful. 

250 pages (large format) MA@}tel=tmletele[-A | =: £19.99 


R. A. Penfold 

This book first covers the basics of simple logic circuits in 
general, and then progresses to specific TTL logic 
integrated circuits. The devices covered include gates, 
oscillators, timers, flip/flops, dividers, and decoder cir- 
cuits. Some practical circuits are used to illustrate the use 
of TTL devices in the “real world”. 

88 pages 

142 pages £5.45 
E. A. Parr 

This book has been written as a designer's guide 
covering many operational amplifiers, serving both as a 
source book of circuits and a reference book for design 
calculations. The approach has been made as non-math- 
ematical as possible. 

[@]co[=)arorele(-M =} atofs} £4.49 


R. A. Penfold 

This book will help you to create and experiment with your 
own electronic designs by combining and using the vari- 
ous standard “building blocks” circuits provided. Where 
applicable, advice on how to alter the circuit parameters 
is provided. 

The circuits covered are mainly concerned with signal 
generation, power supplies, and digital electronics. 

The topics covered in this book include: 555 oscillators; 
sinewave oscillators; function generators; CMOS oscilla- 
tors; voltage controlled oscillators; radio frequency 
oscillators; 555 monostables; CMOS monostables; TTL 
monostables; precision long timers; power supply and 
regulator circuits; negative supply generators and voltage 
boosters; digital dividers; decoders, etc; counters and dis- 
play drivers; D/A and A/D converters; opto-isolators, 
flip/flops, noise generators, tone decoders, etc. 

Over 170 circuits are provided, which it is hoped will be 
useful to all those involved in circuit design and applica- 
tion, be they professionals, students or hobbyists. 

@]ge(-1 metele(-m =] Pad £5.45 

160 pages 

192 pages 

For a further selection 
ro) im olele) Coy -\- dels al:) 4 
two issues of EPE 

R. A. Penfold 
Many electronic hobbyists who have been pursuing their 
hobby for a number of years seem to suffer from the 
dreaded “seen it all before” syndrome. This book is fairly 
and squarely aimed at sufferers of this complaint, plus 
any other electronics enthusiasts who yearn to try some- 
thing a bit different. No doubt many of the projects fea- 
tured here have practical applications, but they are all 
worth a try for their interest value alone. . 
The subjects covered include:- Magnetic field detector, 
Basic Hall effect compass, Hall effect audio isolator, Voice 
scrambler/descrambler, Bat detector, Bat style echo loca- 
tion, Noise cancelling, LED stroboscope, Infra-red “torch”, 
Electronic breeze detector, Class D power amplifier, 
Strain gauge amplifier, Super hearing aid. 

@} vo [=) @rerele (=m =] oe Tal £5.45 


R. A. Penfold 

This book is for complete beginners to electronic project 
building. It provides a complete introduction to the practi- 
cal side of this fascinating hobby, including the following 

Component identification, and buying the right parts; 
resistor colour codes, capacitor value markings, etc; 
advice on buying the right tools for the job; soldering; 
making easy work of the hard wiring; construction meth- 
ods, including stripboard, custom printed circuit boards, 
plain matrix boards, surface mount boards and wire-wrap- 
ping; finishing off, and adding panel labels; getting “prob- 
lem” projects to work, including simple methods of fault- 

In fact everything you need to know in order to get start- 
ed in this absorbing and creative hobby. 

'@) vo (=) arotele (= =] aa is £5.49 


R. A. Penfold 

While fibre-optic cables may have potential advantages 
over ordinary electric cables, for the electronics 
enthusiast it is probably their novelty value that makes 
them worthy of exploration. Fibre-optic cables provide an 
innovative interesting alternative to electric cables, but in 

138 pages 

135 pages 

Project Building & Testing 

most cases they also represent a practical approach to 
the problem. This book provides a number of tried and 
tested circuits for projects that utilize fibre-optic cables. 

The projects include:- Simple audio links, F.M. audio 
link, P-\W.M. audio links, Simple d.c. links, P-\W.M. d.c. link, 
P.W.M. motor speed control, RS232C data links, MIDI 
link, Loop alarms, R.P.M. meter. 

All the components used in these designs are readily 
available, none of them require the constructor to take out 
a second mortgage. 

Order code BP374 £5.45 

132 pages 


We also carry a selection of books 
aimed at readers of EPE’s sister maga- 
zine on vintage radio Radio Bygones. 
These books include the Comprehensive 
Radio Valve Guides (five books with a. 
Free copy of the Master Index) for just 
£15. Also Jonathan Hill’s excellent Radio 
Radio, a comprehensive book with hun- 
dreds of photos depicting the develop- 
ment of the British wireless set up to the 
late 1960s. 

The three volumes of our own Wireless 
For the Warrior by Louis Meulstee are 
also available. These are a technical his- 
tory of radio communication equipment in 
the British Army from pre-war through to 
the 1960s. 

For details see the shop on our UK web 
site at or 
contact us for a list of Radio Bygones 


All prices include UK postage. For postage to Europe (air) and the rest of the world (surface) 
please add £2 per book. For the rest of the world airmail add £3 per book. CD-ROM prices 
include VAT and/or postage to anywhere in the world. Send a PO, cheque, international money 
order (£ sterling only) made payable to Direct Book Service or card details, Visa, Mastercard, 
Amex, Diners Club or Switch — minimum card order is £5 — to: 

Books are normally sent within seven days of receipt of order, but please allow 28 days for 
delivery — more for overseas orders. Please check price and availability (see latest issue of 
Everyday Practical Electronics) before ordering from old lists. 

For a further selection of books see the next two issues of EPE. 
Tel 01202 873872 Fax 01202 874562. Email: dbs 

Order from our online shop at: 


PU TINO. sods tess ccna oo sees ckcoe vcseccdanunianiccaouns 

WGOSS? occ ivsvesincesinsevecsarcoscaesensniacdsesanysdsoctndeesasavecs 

ecaaraudidicaeuaseessacesticsiavent so dastaa POSE COUG! ycacaxestcrviecsnccstneivere TOIODMONG NOS sasescicencuesiuisssivansvivectsaansevadans®s 

MSs rte carerin tytn apcnte es buceqn scree esse) ckarce tea uiceonécgonterteqealanscive eusesayiessycvoueasshet wlsuicusesedeestnevesiaivasteceornesaeedode 
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If you do not wish to cut your magazine, send a letter or copy of this form 

eee eee eee eee eee eee eee eee ee eee eee eee eee eee eee reer 

Everyday Practical Electronics, September 2002 

4-Channel Twinkling Lights DEC ’01 
; Ghost Buster — Mic  _ 
— Main ; 

* PIC Polywhatsit — Digital 

— Analogue 
Printed circuit boards for most recent EPE constructional projects are available from Forever Flasher JAN 02 
the PCB Service, see list. These are fabricated in glass fibre, and are fully drilled and Time Delay Touch Switch 
roller tinned. All prices include VAT and postage and packing. Add £1 per board for *& PIC Magick Musick 
airmail outside of Europe. Remittances should be sent to The PCB Service, Versatile Bench Power Suppl 
Everyday Practical Electronics, Wimborne Publishing Ltd., 408 Wimborne Road % PIC Spectrum Analyser FEB ’02 
East, Ferndown, Dorset BH22 9ND. Tel: 01202 873872; Fax 01202 874562; Versatile Current Monitor , 
E-mail: On-line Shop: www.epemag. Guitar Practice Amp Cheques should be crossed and made payable to * PIC Virus Zapper MAR ’02 

Everyday Practical Electronics (Payment in £ sterling only). 

NOTE: While 95% of our boards are held in stock and are dispatched within 

seven days of receipt of order, please allow a maximum of 28 days for delivery 

| — overseas readers allow extra if ordered by surface mail. 

Back numbers or photostats of articles are available if required — see the Back ontroned 
Issues page for details. * PIC Big Digit Display 

Please check price and availability in the latest issue. Washing Ready Indicator 
Boards can only be supplied on a payment with order basis. Audio Circuits-1 — LM386N-1 

— TDA7052 

— TBA820M 
% Multi-Channel Transmission System 

— LM380N 
— TDA2 
— Transmitter a 

— Twin TDA2003 

World Lamp JUNE ’02 
% Canute Tide Predictor 

RH Meter 
* PIC Mini-Enigma — Software only 
% Programming PIC Interrupts — Software onl 

Simple Audio Circuits—2 — Low, Med and High 
Input Impedance Preamplifiers (Single Trans.) 

JUNE ’00 | 267 £3.05 

% PIC-Gen Frequency Generator/Counter JULY ’00 | 268 £5.07 Low-Noise Preamplifier (Dual Trans.) 
g-Meter 269 £4.36 Tone Control | 
EPE Moodloop Neem 271 5.47 Bandpass Filter 
| Quiz Game Indicator ; 272 £4.52 § § Frequency Standard Generator — Receiver 
Handy-Amp 273 £4.52 — Digital 
Active Ferrite Loop Aerial Taam 74 £4.67 * Biopic Heartbeat Monitor 
% Remote Control |R Decoder § Software only -- Simple Audio Circuits — 3 JULY ’02 
%& PIC Dual-Channel Virtual Scope Ce = 275 — Dual Output Power Supply 

— Crossover/Audio Filter 
Infra-Red Autoswitch 
% EPE StyloPIC 
Rotary Combination Lock — Main Board 
— Interface Board > 

% Using the PIC’s PCLATH Command — Software onl 
Big-Ears Buggy Olen 
% PIC World Clock 
Simple Audio Circuits—4 

Low Freq. Oscillator 

Resonance Detector 
Vinyl-To-CD Preamplifier SEPT ’02 
% Freebird Glider Control 
% Morse Code Reader 


Software programs for EPE projects marked with a single asterisk * are available on 3-5 inch 
PC-compatible disks or free from our Internet site. The following disks are available: PIC 

Handclap Switch NOV ’00 | 270 
% PIC Pulsometer Software only 
Twinkling Star 
Festive Fader 
Motorists’ Buzz-Box 
% PiCtogram 
% PIC-Monitored Dual PSU-1 PSU 
Monitor Unit 
Static Field Detector (Multi-project PCB) 
Two-Way Intercom 
UFO Detector and Event Recorder 
Magnetic Anomaly Detector 
Event Recorder 
Audio Alarm 
% Using PICs and Keypads 

Ice Alarm 
% Graphics L.C.D. Display with PICs (Supp) 
Using the LM3914-6 L.E.D. Bargraph Drivers 
Multi-purpose Main p.c.b. 

Relay Control 

Software only 

L.E.D. Display Tutorial (Mar-May ’98); PIC Toolkit Mk2 V2-4d (May-Jun ’99); EPE Disk 1 (Apr ’95-Dec ’98); 

% PC Audio Power Meter Software only EPE Disk 2 (1999); EPE Disk 3 (2000); EPE a 4 (2001); EPE Disk 5 (Jan 2002 issue to 
Doorbell Extender. Transmitter MAR ’01 current cover date); EPETeach-In 2000; EPE Spectrum; EPE Interface Disk 1 (October '00 
‘Receiver issue to current cover date). * * PIC Toolkit TK3 software (Nov ’01) is on CD-ROM. The 3-5 

Trans/Remote inch disks are £3.00 each (UK), the CD-ROM is £6.95 (UK). Add 50p each for overseas sur- 

Rec./Relay face mail, and £1 each for airmail. All are available from the EPE PCB Service. All files can 

be downloaded free from our Internet FTP site: 
EPE Snug-bug Heat Control for Pets : 
Intruder Alarm Control Panel 

Main Board 
External Bell Unit 

Order Code Project Quantity Price 

Hosepipe Controller JUNE ’01 301 
Magfield Monitor (Sensor Board) 302 
Dummy PIR Detector 303 

% PIC16F87x Extended Memory Software only 
Stereo/Surround Sound Amplifier JULY ’01 
Perpetual Projects Uniboard—1 
Solar-Powered Power Supply & Voltage Reg. 
MSF Signal Repeater and Indicator 
Repeater Board 
Meter Board 
* PIC to Printer Interface 
Lead/Acid Battery Charger 
Shortwave Loop Aerial 
* Digitimer — Main Board 
— R.F. Board 
Perpetual Projects Uniboard—2 
L.E.D. Flasher — Double Door-Buzzer 
Perpetual Projects Uniboard—3 
Loop Burglar Alarm, Touch-Switch Door-Light 
and Solar-Powered Rain Alarm 
L.E.D. Super Torches — Red Main 
— Display Red 
— White L.E.D. 

Practical Electronics 

MasterCard, Amex, Diners 
Club, Visa or Switch 

Diners Chib 

%& Sync Clock Driver 

%& Water Monitor 

Camcorder Power Supply 

PIC Toolkit Mk3 

Perpetual Projects Uniboard—4. Gate Sentinel, Solar- 

powered Bird Scarer and Solar-Powered Register 

Teach-In 2002 Power Supply 

Lights Needed Alert 

Pitch Switch 

Capacitance Meter — Main Board (double-sided) 
— Display Board (double-sided) 

* *& PIC Toolkit TK3 — Software only 

Care EXO. Dali scissravideccavereusucincsvaics Switch Issue No............ 

SINAC yaa cds seas cts set-aevic a cannaega nia snbedesrsetavaceteraedeneest 

NOTE: You can also order p.c.b.s by phone, Fax, Email or via our 
Internet site on a secure server: 


Everyday Practical Electronics, September 2002 | 691 


Over 800 pages 

In-depth theory 

Projects to build 

Detailed assembly instructions 
Full components checklists 
Extensive data tables 
Manufacturers’ web links 
Easy-to-use Adobe Acrobat 

Clear and simple layout 
Comprehensive subject range 
Professionally written 

Regular Supplements 


The revised CD-ROM edition of the Modern Electronics Base 
Manual (MEM) contains practical, easy-to-follow information on the 
following subjects: 

Electronic Components and their 
Characteristics (16 sections from Resistors and Potentiometers to 
Crystals, Crystal Modules and Resonators); Circuits Using Passive 
Components (10 sections); Power Supplies; The Amateur 
Electronics Workshop; The Uses of Semiconductors; Digital 
Electronics (6 sections); Operational Amplifiers; Introduction to 
Physics, including practical experiments; Semiconductors 
(5 sections) and Digital Instruments (3 sections). 

There's nothing to beat the satisfaction of 
creating your own projects. From basic principles, like soldering 
and making printed circuit boards, to the tools needed for 
circuit-building, the Modern Electronics Manual and its 
Supplements describe clearly, with appropriate diagrams, how to 
assemble a radio, loudspeaker circuits, amplifiers, car projects, 

a computer interface, measuring instruments, workshop 
equipment, security systems, medical and musical circuits, etc. 
The Base Manual describes 12 projects including a Theremin 
and a Simple TENS Unit. 

Extensive tables on diodes, transistors, 
thyristors and triacs, digital and linear i.c.s. 

Should you come across a technical 
word, phrase or abbreviation you're not familiar with, simply look 
up the glossary included in the Manual and you'll find a 
comprehensive definition in plain English. 

The Manual also covers 
component and equipment 
The most comprehensive reference work ever produced at a price 
you can afford, the CD-ROM edition of THE MODERN 
ELECTRONICS MANUAL provides you with all the essential 
information you need. 

and provides web links to 

Revised CD-ROM Edition of Basic Work: Contains over 800 pages of information in Adobe Acrobat format. Edited by John Becker. 
Regular Supplements: Additional CD-ROMs each containing approximately 500 pages of additional information on specific areas of 
electronics will be available for £19.95 each. Information on the availability and content of each Supplement CD-ROM will be sent to you as they 

become available. 

Presentation: CD-ROM suitable for any modern PC. Requires Adobe Acrobat Reader which is included on the MEM CD-ROM. 

Price of the Basic Work: £29.95 POST FREE. 



SAFETY: Be knowledgeable about Safety Regulations, Electrical Safety and First Aid. 

UNDERPINNING KNOWLEDGE: Specific sections enable you to Understand Electrical 
and Electronic Principles, Active and Passive Components, Circuit Diagrams, Circuit 
Measurements, Radio, Computers, Valves and Manufacturers' Data, etc. 

PRACTICAL SKILLS: Learn how to identify Electronic Components, Avoid Static 
Hazards, Carry Out Soldering and Wiring, Remove and Replace Components. 

TEST EQUIPMENT: How to Choose and Use Test Equipment, Assemble a Toolkit, Set 
Up a Workshop, and Get the Most from Your Multimeter and Oscilloscope, etc. 

SERVICING TECHNIQUES: The regular Supplements include vital guidelines on how to 
Service Audio Amplifiers, Radio Receivers, TV Receivers, Cassette Recorders, Video 
Recorders, Personal Computers, etc. 

TECHNICAL NOTES: Commencing with the IBM PC, this section and the regular 
Supplements deal with a very wide range of specific types of equipment — radios, TVs, 
cassette recorders, amplifiers, video recorders etc.. 

REFERENCE DATA: Detailing vital parameters for Diodes, Small-Signal Transistors, 
Power Transistors, Thyristors, Triacs and Field Effect Transistors. Supplements include 
Operational Amplifiers, Logic Circuits, Optoelectronic Devices, etc. 

(ESM - Printed version only) : 

Basic Work: Contains around 900 pages of information. Edited by Mike Tooley BA 
Regular Supplements: Unlike a book or encyclopedia, this Manual is a living work — 
continuously extended with new material. If requested, Supplements are sent to you on 
approval approximately every three months. Each Supplement contains around 160 pages 
— all for only £23.50+£2.50 p&p. You can, of course, return any Supplement (within ten 
days) which you feel is superfluous to your needs. You can also purchase a range of past 
Supplements to extend your Base Manual on subjects of particular interest to you. 
Presentation: Durable looseleaf system in large A4 format 

Price of the Basic Work: £29.95 
(to include a recent Supplement FREE). 

The essential work for 
servicing and repairing 
electronic equipment 

@ Around 900 pages 

@ Fundamental principles 

@ Troubleshooting techniques 
@ Servicing techniques 

@ Choosing and using test 

Reference data 

Easy-to-use format 

Clear and simple layout 

Vital safety precautions 
Professionally written 

@ Regular Supplements 

@ Sturdy gold blocked ring-binder 

Eel & waran t P P seen 

Our 30 day money back guarantee gives you complete peace of mind. If you are not entirely happy with the Electronics Service 
Manual, for whatever reason, simply return it to us in good condition within 30 days and we will make a full refund of your 
payment — no small print and no questions asked. All we ask is that you pay the return postage. (Overseas buyers also have to 

pay our overseas postage charge). Sorry, but we can only make exchanges on the Modern Electronics Manual (CD-ROM 
version) if the CD-ROM is faulty, we cannot offer a money back guarantee on this product as the content can be printed out. 


eelelelelelelelelfelrelelrelelpelelfelrelelpelfelfelrelfelrelelelrelelelelalrelelelelelelelelelelelealelealel eels eee eee alee eee eee eee eee eae 

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i i Sm titular i ei il i et 


Everyday Practical Electronics reaches twice as 
many UK readers as any other UK monthly hobby 
electronics magazine, our sales figures prove it. 
We have been the leading monthly magazine in 
this market for the last seventeen years. 

If you want your advertisements to be seen by the largest readership at the most economical price our classified and semi-display 
pages offer the best value. The prepaid rate for semi-display space is £8 (+VAT) per single column centimetre (minimum 2-5cm). 

The prepaid rate for classified adverts is 30p (+VAT) per word (minimum 12 words). 

All cheques, postal orders, etc., to be made payable to Everyday Practical Electronics. VAT must be added. Advertisements, together 
with remittance, should be sent to Everyday Practical Electronics Advertisements, Mill Lodge, Mill Lane, Thorpe-le-Soken, Essex CO16 

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For rates and information on display and classified advertising please contact our Advertisement Manager, Peter Mew as above. 

a X-10® Home Automation 

SMeoD Cost teed We put you in control™ 


High quality robot kits and components 
UK distributor of the OOPic microcontroller 

Secure on-line ordering 
Rapid delivery 
Highly competitive prices 

Why tolerate when you can automate? 

An extensive range of 230V X-10 products 
| and starter kits available. Uses proven Power 
Line Carrier technology, no wires required. 

Products Catalogue available Online. 
Worldwide delivery. 

Laser Business Systems Ltd. 
a eae info "VISA $ Seess) 

Tel: (020) 8441 9788 

Fax: (020) 8449 0430 

O30) (0) (0) 41, 01-0 a P40, 

FR-4, 1.5 mm, 35/35 um copper, 
160x100 mm, double side, PTH, 
soldermask, component silkscreen 
production in 3-5 working days 
made in Bulgaria 
no import tax to Europe, UK and US 


Tel: 0208 823 9220 


Transformers and Chokes for all types 
of circuits including specialist valve units 
Custom design or standard range 

High and low voltage 
Variable Voltage Technology Ltd 
Unit 24 Samuels Whites Estate 
Cowes, Isle of Wight PO31 7LP 

Tel: 01983 280592 Fax: 01983 280593 

PICmicro Controllers 
16F628 $4.22, 16F877 $11.31 

Wisp628 Programmer 

in-circuit Flash PIC programmer kit $21 
S/H $7, prices incl. VAT 


Next course commences 
16th SEPTEMBER 2002 

Mo), |e) 1m ons -0)\ | (ox-mere) MMe] = 
TEL: (020) 7373 8721 


Z<ses 128K AND 512K — OZ4 


PHONE/FAX 01494 871319 
E-mail: wnr 


EPE FTP site: 

Access the FTP site by typing the above into your web browser, or by setting up an FTP session using 

appropriate FTP software, then go into quoted sub-directories: 

PIC-project source code files: /pub/PICS 

PIC projects each have their own folder; navigate to the correct folder and open it, then fetch all the files 
contained within. Do not try to download the folder itself! 

EPE text files: /pub/docs 

Basic Soldering Guide: solder.txt 

Ingenuity Unlimited submission guidance: ing_unlt.txt 

New readers and subscribers info: epe_info.txt 

Newsgroups or Usenet users advice: usenet.txt 

Ni-Cad discussion: and 

Writing for EPE advice: write4us.txt 

You can also enter the FTP site via the link at the top of the main page of our home site at: ; 

Shop now on-line: 


exists to help electronics enthusiasts by personal 
contact and through a quarterly Newsletter. 

For membership details, write to the Secretary: 

Mr. T. S. C. Samuel-Mauryce 
3A Colliery Street, off Clayton Lane, 
Openshaw, Manchester M11 2AW, Lancs, UK 
Tel: 0161 223 3208 after 6 pm 
Email: tsc.samuel-mauryce02 

Please send s.a.e. for information 

Valve Output Transformers: Single ended 50mA, £4.50; push/pull 
50W, £38; 100W, £53. Mains Transformers: Sec 220V 30mA 6V 
1A, £3; 250V 60mA 6V 2A, £5; 250V 80mA 6V 2A, £6. High 
Voltage Caps: 50uF 350V, 68uF 500V, 150uF 385V, 220uF 400V, 
330uF 400V, 470uF 385V, all £3 ea., 32+32uF 450V £5, 4uF 800V 
oil filled paper block £10, 10H 200mA choke £14. Postage extra. 
Record Decks and Spares: BSR, Garrard, Goldring, motors, 
arms, wheels, headshells, spindles, etc. Send or phone your want 
list for quote. 


md SURREY, CRO 2HS. Tel: (020) 8684 1665 
Lots of transformers, high volt caps, valves, output transformers, speakers, in stock. 
Phone or send your wants list for quote. : 
Quality Components at lowest ever price 

Mail order only — we do not deal in credit cards 
If we have not got it we send you a cheque back 

We only deal in Cheques or Postal Orders 

Phone 01843 570905 


Contact Will Outram for your 
Electronic Components 

Email: sales @ 
7 Bakewell Road, Baslow, Derbyshire DE45 1RE 
Tel/Fax: 01246 583777 

Send 41p stamp for catalogue 


BOARDS! Free prototype p.c.b. with quantity orders. 
Call Patrick on 028 9073 8897 for details. Agar 
Circuits, Unit 5, East Belfast Enterprise Park, 308 
Albertbridge Road, Belfast BTS 4GX. 

VICE. Prototype and production artwork raised from 
magazines or draft designs at low cost. PCBs designed 
from schematics. Production assembly, wiring and soft- 
ware programming. For details contact Patrick at Agar 
Circuits, Unit 5, East Belfast Enterprise Park, 308 
Albertbridge Road, Belfast, BTS 4GX. Phone 028 9073 
8897, Fax 028 9073 1802, Email 
G.C.S.E. ELECTRONICS KITS, at pocket money ~ 
prices. S.A.E. for FREE catalogue. SIR-KIT 
Electronics, 52 Severn Road, Clacton, CO15 3RB. 

STOCK -— please ring for free list. Valve equipment 
repaired. Geoff Davies (Radio). Phone 01788 574774. 
ELECTRONICS ENGINEER available to develop your 
prototype project from schematic drawing to assembled 
p.c.b. Phone 01633 895580. Mobile 07748 658567. 
TRONICS CONSTRUCTOR. Send s.a.e. for product 
list to: metaStable Electronics, PO Box 3103, Sheffield, 
S11 7WW. Visit www.metastable.electronics.btinter 

694 Everyday Practical Electronics, September 2002 


80-046 Electronic digital caliper for 
both imperial (0-6 inches) and metric 
(0-150mm). Accuracy +/-0.001”". 
Simple touch button facility to change 

from metric to imperial (and vice versa). 

On/off and zero button, inside and 
outside measuring plus locking screw 
to hold measurement. Uses a standard 
watch battery (included). Metal 
construction. Supplied in a neat plastic 
storage case. £34.95 

80-042 Switch mode PSU (ATX type) 
for computers. Mains input to DC 
output. +5V @ 32A,+3.3V @ 25A, +12V 
@ 8.5A, -5V @ 0.4A, -12V @ 0.7A, +5V 
(aux) @ 0.75A, maximum 330W. Made 
by AC Bel, Part No. API7506. Case size 
150 x 145 x 105mm. Fan cooled. 

80-082 Test leads with crocodile clips. 
4mm plug one end to an insulated 
crocodile clip the other. One red and 
one black. 200mm iong. £1.00 


56-067 CR2016 lithium battery. 3V. 
20mm diameter x 1.6mm high. £1.00 
56-068 CR2025 lithium battery. 3V. 
20mm diameter x 2.5mm high. £1.00 
42-544 Lithium button cell, CR2032. 
3V, 20mm diameter x 3.2mm thick. 
Brand new (not surplus). £1.00 

48-077 ‘AA’ size Nickel Metal Hydride 
rechargeable battery. 1.2V, 1200mAh 
with nipple. Brand new. £1.75 

38-403 Pack of 3 ‘AA’ Ni-Cads, 650mA. 
Soldered together with a 2” lead to a 2 
pin socket giving them a total of 3.6V, 
650mA. You could split them up or join 
them together. Only £1.25 

56-095 AAA rechargeable Ni-Cads. 
240mAH. Supplied on cards of 4. Was 4 
for £4.00. Now only £2.00 

38-283 Mixture pack of LED's. All sorts 
of shapes and sizes and colours. Pack 
of 100 £3.50 


48-111 Vibrating motor designed for 
pagers and mobile phones. 20mm long 
x 7mm diameter. Works between 3V 
oo. 6V. Very small and excellent quality. 


Brand new and boxed but with original purchasing organisation’s small identifying mark on 
case. With test leads and handbook. List price £150. Our price £47.50. P&P £6.50. 

A DIGITAL HANDHELD LCR METER. Measuring inductance, capacitance, resistance. 
LCD display. Range 2mH to 20H inductance. 2000pF to 200uF capacitance. 200 ohm to 
20 megohm resistance. Brand new with test leads and manual. £44.00. P&P £4. 

12V D.C. TO 240V A.C. 300 WATT POWER INVERTER. Ideal for use in your caravan, car, 
boat, to run TV, lighting, fridges, recharge your mobile phone, etc. Compact size, brand 
new and boxed, fully guaranteed. £49.50, p&p £6.50. 

250 % watt metal/carbon film resistors £1 
30 5mm red l.e.d.s 



10V, 12V, 16V, 22V, 27V, 33V. All 400mW. 
20 for £1. 

BC558 5 
OC42 Military spec : 3 

555 Timer chips 3 
IEC 3-pin mains input chassis socket £1 

220uF electrolytics, 10V £1 


10V, 15V, 33V, 47V. All SW. 8 for £1. 
120V, 600mW. 10 for £1. 

ELECTRIC UFOs by Albert Budden. The effects of electromagnetic pollution, UFOs, 
fireballs, abnormal states. 286 pages, photos. £10. 

building valve amplifiers, pre-amps, tuners, circa 1958. 48 large format pages, facsimile 
copy. £12.50. 
data, base connections, characteristics and operating conditions for Mullard valves and 
their eqivalent makes. Facsimile reprint. £16.50, p&p £2.25. 


5 High voltage capacitors, 0-1uF 1000V axial 

5 0-05uF 600V axial 

50 Vintage carbon one watt resistors. Useful values £3 

15 100 ohm wirewound resistors, 3W £1 

Valveholders, Octal, B7G, B9A (state which) 

68uF 450V wkg electrolytics, 1%4in. x %4in. dia. 

47uF 400V wkg electrolytic, %4in. x 34in. dia. 




22uF 250V wkg electrolytic, 1in. x %in. dia. axial £1 
47uF mixed dielectric axial capacitors, 250V wkg £1 
10uF 400V electrolytic, tin. x ‘in. dia. axial £2 
Terminal block 4 screw terminals, 2%in. length with 
fixing holes £1 

Send 2 first class stamps for the Electronic Surplus Trader — our latest catalogue full 
of component bargains, valves, high voltage capacitors, obsolete semiconductors etc. 

P&P £1 .60 under £10. Over Free unless otherwise stated. 


157 Dickson Road, BLACKPOOL FY1 2EU 
Tel: (01253) 751858. Fax: (01253) 302979 
E-mail: Telephone Orders Accepted 

Everyday Practical Electronics, September 2002 

80-078 Mains PSU, 220-240V AC input, 
15V DC, 800mA output. Plug in the wall 
type. 2m flying lead to a 2.1mm power 
socket. £3.95 

80-102 IDE hard disk drive cable with 
3 x 40 way IDC sockets so you can have 
two hard drives running off the same 
motherboard. 580mm long. £1.50 
80-103 Floppy disk drive cable to 
enable the use of up to 2 floppy disk 
drives. Has 3 x 34 way IDC sockets and 
2 x 34 way card edge connectors 
mounted on a 650mm long ribbon 
cable. £1.50 

80-104 Ribbon cable lead, 450mm 
long with 3 x 40 way IDC sockets for 
use with hard drives and CD ROM's. 
Also included is a 4 pin in-line socket to 
a4 pin in-line socket lead for internal 
CD ROM audio connection. £2.00 

38-484 MES lamp holder with two 
screw fixing holes for mounting. Screw 
terminals for connection. White. £1.00 
For Pack Of 4 

§6-155 KBPC3501 bridge rectifier. 
100V, 35Amp. £2.50 each | 

48-140 PVC electrical tape, 
19mm wide x 0.15mm thick x 33 
metres long. Flame retardant, 
BS3924. 75p 

80-045 12V, 17Ah, lead acid, sealed 
rechargeable battery. Gel type. Brand 
new. 180 x 165 x 75mm. These are 
usually around £45.00 each to buy. 

-§6-006 Brand new 12V DC fan. 80 x 80 

x 25mm with 10” red and black lead. 

WCN Supplies 
Dept EE - The Old Grain Store 
Rear Of 62 Rumbridge Street 
Totton - Southampton - $040 9DS 

Telephone or Fax On 
023 8066 0700 

Email: info@wensupplies. 

ADD £2.25 FOR P & P 


Looking for ICs TRANSISTORS? 
A phone call to us could get a result. We 
offer an extensive range and with a world- 
wide database at our fingertips, we are 
able to source even more. We specialise in 
devices with the following prefix (to name 

but a few). 

We can also offer equivalents (at customers’ risk) 
We also stock a full range of other electronic components 
Mail, phone, Fax Credit Card orders and callers welcome 




. value. a \ 

pital ae 










SP 126 




& Wire, 

40-42 Cricklewood Broadway, 
London, NW2 3ET 

Tel: 020 8450 0995 
Fax: 020 8208 1441 
Email: sales 

The Catalogue is FREE to shop callers or send £2 to cover postage. 

15 x 5mm Red LEDs 
12 x 5mm Green LEDs 
12 x 5mm Yellow LEDs 
15 x 3mm Red LEDs 
12 x 3mm Green LEDs 
10 x 3mm Yellow LEDs 
100 x 1N4148 diodes 
30 x 1N4001 diodes 
30 x 1N4002 diodes 
20 x BC182 transistors 
20 x BC 184 transistors 
20 x BC212 transistors 
20 x BC549 transistors 
4 x CMOS 4001 
4 x 555 timers 
4 x 741 Op.Amps 
4 x CMOS 4011 
3 x CMOS 4013 
20 x 1N914 diodes 
25 x 10/25V radial elect. caps. 
12 x 100/35V radial elect. caps. 
10 x 470/16V radial elect. caps. 
15 x BC237 transistors 
20 x Mixed transistors 
200 x Mixed 0-25W C-F. resistors 
5 x Min. PB switches 
4 x 5 metres stranded core wire 
20 x 8-pin DIL sockets 
15 x 14-pin DIL sockets 
15 x 16-pin DIL sockets 
4 x 74LS00 
15 x BC557 transistors 
4 x CMOS 4093 
3 x 10mm Red LEDs 
3 x 10mm Green LEDs 
20 x Assorted ceramic disc caps 
8 x Battery clips — 4 ea. 
PP3 + PP9 
100 x Mixed 0-5W C.F. resistors 
2 x TLO71 Op.Amps 
20 x 1N4004 diodes 


5 each value — total 3650-25W £3.00 
10 each value — total 730 0-25W £4.25 
1000 popular values 0-25W £6.15 
5 each value-total 365 0-5W £4.00 
10 each value-total 730 0-5W £6.65 
1000 popular values 0-5W £8.40 

SP 134 



SP 168 


Buy 10 x £1 Special Packs and choose another one FREE 

15 x 1N4007 diodes 
6 x Miniature slide switches 
3 x BFY50 transistors 
4 x W005 1-5A bridge rectifiers 
20 x 2-2/63V radial elect. caps. 
3 x W04 1-5A bridge rectifiers 
2 x CMOS 4017 
5 Pairs min. crocodile clips 
(Red & Black) 
6 x ZTX300 transistors 
10 x 2N3704 transistors 
5 x Stripboard 9 strips x 
25 holes 
4 x 8mm Red LEDs 
4 x 8mm Green LEDs 
4 x 8mm Yellow LEDs 
15 x BC548 transistors 
3 x Stripboard, 14 strips x 
27 holes 
10 x 2N3904 transistors 
10 x 2N3906 transistors 
2 x LF351 Op.Amps 
20 x 1N4003 diodes 
6 x BC107 transistors 
6 x BC108 transistors 
4 x Standard slide switches 
20 x 22/25V radial elect. caps 
20 x 1/63V radial elect. caps. 
10 x 1A 20mm quick blow fuses 
20 x 4-7/63V radial elect. caps. 
20 x BC547 transistors 
15 x BC239 transistors 
4 x 5 metres solid core wire 
3 x CMOS 4066 
3 x 10mm Yellow LEDs 
6 x 20 pin DIL sockets 
5 x 24 pin DIL sockets 
5 x 2-5mm mono jack plugs 
5 x 2-5mm mono jack sockets 

2002 Catalogue now available £1 

inc. P&P or FREE with first order. 

P&P £1.25 per order. NO VAT 

Orders to: 

Sherwood Electronics, 
7 Williamson St., Mansfield, 

Notts. NG19 6TD. 

Watch Slides on TV. 

Make videos of your slides. Digitise your slides 
(using a video capture card) 

“Liesgang diatv’ automatic slide viewer with built in 
high quality colour TV camera. It has a composite 
video output to a phono plug (SCART & BNC adaptors 
are available). They are in very good condition with few 
signs of use. More details see 
£91.91 + VAT = £108.00 

Board cameras all with 512 x 582 pixels 8-5mm 1/3 inch sensor and composite video 
out. All need to be housed in your own enclosure and have fragile exposed surface 
mount parts. They all require a power supply of between 10V and 12V DC 150mA. 
47MIR size 60 x 36 x 27mm with 6 infra red LEDs (gives the same illumination as a 
small torch but is not visible to the human eye) £37.00 + VAT = £43.48 
3SOMP size 32 x 32 x 14mm spy camera with a fixed focus pin hole lens for hiding 
behind a very small hole £35.00 + VAT = £41.13 
40MC size 39 x 38 x 27mm camera for ‘C’ mount lens these give a much sharper 
image than with the smaller lenses £32.00 + VAT = £37.60 

Economy C mount lenses all fixed focus & fixed iris 

VSL1220F 12mm F1.6 12 x 15 degrees viewing angle £15.97 + VAT £18.76 
VSL4022F 4mm F1-22 63 x 47 degrees viewing angle £17.65 + VAT £20.74 
VSL6022F 6mm F1-22 42 x 32 degrees viewing angle £19.05 + VAT £22.38 
VSL8020F 8mm F1-22 32 x 24 degrees viewing angle £19.90 + VAT £23.38 

Better quality C Mount lenses 

VSL1614F 16mm F1-6 30 x 24 degrees viewing angle £26.43 + VAT £31.06 

VWL813M 8mm F1.3 with iris 56 x 42 degrees viewing angle £77.45 + VAT = £91.00 

1206 surface mount resistors E12 values 10 ohm to 1M ohm 
100 of 1 value £1.00+VAT — 1000 of 1 value £5. ba + VAT 

866 battery pack originally intended to be 

used with an orbitel mobile telephone it con- 

tains 10 1-6Ah sub C batteries (42 x 22 dia. 

the size usually used in cordless screw- 

drivers etc.) the pack is new and unused 

and can be broken open quite easily 

£7.46 + VAT = £8.77 

£1.95 postage & packing per order 

Please add £1.66 + vat = 

Shaws Row, Old Road, Chesterfield, S40 2RB. 
Tel 01246 211202 Fax 01246 550959 
Callers welcome 9.30 a.m. to 5.30 p.m. Monday to Saturday 








Cover (iv)/673 







Phone/Fax: (01255) 861161 

For Editorial address.and phone numbers see page 635 

Published on approximately the second Thursday of each month by Wimborne Publishing Ltd., 408 Wimborne Road East, Ferndown, Dorset BH22 9ND. Printed in England by Apple Web Offset Ltd., Warrington, 
WAI 4RW. Distributed by COMAG Magazine Marketing, Tavistock Rd., West Drayton, UB7 7QE. Subscriptions INLAND: £15 (6 months); £28.50 (12 months); £52 (2 years). OVERSEAS: Standard air ser- 
vice, £18 (6 months); £34.50 (12 months); £64 (2 years). Express airmail, £27 (6 months); £52 (12 months); £99 (2 years). Payments payable to “Everyday Practical Electronics”, Subs Dept, Wimborne Publishing 
Ltd. Email: subs EVERYDAY PRACTICAL ELECTRONICS is sold subject to the following conditions, namely that it shall not, without the written consent of the Publishers first 
having been given, be lent, resold, hired out or otherwise disposed of by way of Trade at more than the recommended selling price shown on the cover, and that it shall not be lent, resold, hired out or otherwise 
disposed of in a mutilated condition or in any unauthorised cover by way of Trade or affixed to or as part of any publication or advertising, literary or pictorial matter whatsoever. 

> for all popular 
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WIT WOrKEd EXaMpies.. The C Comp lers support a range off p ogrammers including — 
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fe) a eae) ae lala (iT new range of quality loudspeakers, designed to take advantage 

’ fitted grilles, wide dispersion constant donee homs, extruded aluminium comer protection and ste 

ball comers, complimented with heavy duty black covering. The enclosures are fitted as standard wi 
top hats for optional loudspeaker stands. The FC15-300 incorporates a large 16 X 6 inch hom. / 


10,000’s cabinets are fitted with the latest Speakon connectors for your convenience and safe’ 
SOLD Five models to choose from. 




FOUR MODELS:- MXF200 (100W + 100W) MXF400 (200W + 200W) 
MXF600 (300W + 300W) MXF900 (450W + 450W) 

FEATURES:- * Independent power supplies with, two toroidal _ transformers 
* Twin L.E.D. Vu Meters * Level controls * Illuminated on/off switch * Jack /XLRinputs * 
Speakon Outputs *Standard 775mv i ih Yoke uts "Open and Short circuit proof * Latest Mos-Fets 
for stress free delivery into virtually any loa igh slew rate * Very low distortion * Aluminium 

cases * MXF600 & MXF900 fan cooled Evin C. Loudspeaker and thermal sebchstcndll 


MXF200 W19” D11” H3'/” (2U 

MXF400 W19” D12” H5/ : 
SIZES:- MXF600 W19” D13” H5'/.” (3U 

MXF900 W119” Bit’ Her) 3U 

PRICES:- MXF200 £175.00 MXF400 £233.85 

ibl FC15-300 WATTS Freq Range 35Hz-20kHz,Sens 101dB, Size H695 W502 D415mm 
Price:- £299.00 per pair 
ibl FC12-300 WATTS Freq Range 45Hz-20kHz, Sens 96dB, Size H600 W405 D300mm 
Price:- £249.00 per pair 
ibl FC12-200 WATTS Freq Range 40Hz-20kHz, Sens 97dB, Size H600 W405 D300mm 
Price:- £199.00 per pair 
ibl FC12-100 WATTS Freq Range 45Hz-20kHz, Sens 100dB, Size H546 W380 D300mm 
MXF600 £329.00 MXF900 £449.15 Price:- £179.00 per pair 
SPECIALIST CARRIER DEL £12.50 Each ibl WM12-200 WATTS Freq Range 40Hz-20kHz, Sens 97dB, Size H418 W600 D385mm 

CATALOGUE 2001-20020 = = se cans Price:- £125.00 Each 

SPECIALIST CARRIER DEL:- £12.50 per pair, wedge monitor £7.00 each 
Optional Metal Stands PRICE:- £49.00 per pair Delivery:- £6.00 




Advanced 3-Way Stereo Active Cross-Over (Switchable two way), housed in a 19” x 1U case. Eac 
channel has three level controls: Bass, Mid & Top. The removable front facia allows access to th! 
programmable DIL switches to adjust the cross-over frequency: There are two versions available 
XO3-S Bass-Mid 125/250/500Hz, Mid-Top 1.8/3/5kHz, all at 24 dB per octave 

: ‘all at 24 dB per Octave 
Please make sure you ask for the correct model when ordering. The 2/3 way selector switches a 
also accessed by removing the front facia. Each stereo channel can be configured separately. Bas 
Invert Switches are incorporated on each channel. Nominal 775mV input/output. Fully compatib 
with the OMP Rack Amplifier and Modules. 

BOTH MODELS PRICED AT :- £117.44 + £5.00 P&P 

These modules now enjoy a world-wide reputation for quality, reliability and performance at a realistic price. F 
models are available to suit the needs of the professional and hobby market .ie. Industry, Leisure, Instrumen 
and Hi-Fi etc. When comparing prices, NOTE that all models include toroidal power supply, integral heatsi 
glass fibre P.C.B. and drive circuits to power a compatible Vu meter. All models are open and short circuit pro 


OMP/MF 100 Mos-Fet Output Power 110 wat 
R.M.S. into_4 ohms,frequency response 1Hz 
100kHz a Dam ping actor >300, Slew Rat 
45V/uS b. typical 0.002%, Input Sensitivi 
500mvV, SN dB. Size 300 x 123 x 60m 
Driggs £42.85 + £4.00 P&P 

OMP/MF 200 Mos-Fet Output Power 200 wati 
Lurnall. £ules@ holes. uss R.M.S. into_4 ohms,frequency response 1Hz 
| Web 32@ = “WT elas) e269 of "Zi 100kHz eas Damping actor >300, Slew Ra 
ne : nis he oe —_ “s 50V/uS Wpical 0.001% Input Sensitivil 

FT Fron 

: Unit 1, Comet way, Southeni-GreSe a 
 Besex. 22 6y rt 
Vets O17 A2-S" 747" Fax: 01707-420243 

500mvV, 3. N o 110dB. Size 300 x 155 x 100m 
Price:- £66.35 + £4.00 P&P 

OMP/MF 300 Mos-Fet Output Power 300 watt 
R.M.S. into_4 ohms,frequency response 1Hz 
100kHz -3dB, Damping Factor >300, Slew Rat 
60V/uS, T.H.D. typical 0.001%, Input Sensitivit 
500mvV, S.N.R. 1 Size 330 x 175 x 100m 

Price:- £83.75 + £5.00 P&P 

OMP/MF 450 Mos-Fet Output Power 450 watt 
R.M.S. into _4 ohms,frequency response 1Hz 
100kHz -3dB, Damping Factor >300, Slew Rat 
Povius, T.H. .D: - typical 0.001 % , Input Se Sensitivit 
500m S.N ooled 
reudeneeker Protection. Zz Second Anti Thum 
Delay. Size 385 x 210 x 105m 

Price:- £135.85 + £6. 00 P&P 

OMP/N ties Mos-Fet Output Power 1000 watt 
R.M.S. into 2 ohms, frequency response 1Hz 
PeyNS, Bune Damp ping actor >300, Slew Rat 

HD. Ee ga » Input Sensitivit 
com j 




>100dB * SUPPLY 230V A.C. *WEIGHT 2.7Kg * SIZE H254 X W254 X D94mm 


£117.44 +£5.00 P&P INCL. V.A.T. CHECK WEBSITE FOR PANELS UP TO 500W B. K. Ee i E Om @) N [ CS 

FROM SCHOOL, COLLEGES, GOVE OFICIAL ORDERS Fle EL.: 01702-527572 FAX.: 01702-420243 

INCLUSIVE OF VAT SALES COUNTER, CR = Web:- http: / E-Mail sales 

ooled, D.C 
ee Protection, a Second Anti Thum 
Delay. Size 422 x 300 x 

Price:- £261. 00 + ED. 00 P&P