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©
2004, Wimborne Publishing Ltd
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ISSN 0262 3617
PROJECTS . . . THEORY . . . NEWS . . .
COMMENTS . . . POPULAR FEATURES . . .
VOL. 33. No. 11 NOVEMBER 2004
Cover illustration: Keith Kent/Science Photo Library
www.epemag.wimborne.co.uk
EPE Online:
www.epemag.com
Projects and Circuits
THUNDERSTORM MONITOR
by Thomas Scarborough
An early warning monitor of pending thunderstorms
LOGIC PROBE
by Anthony H. Smith, BSc. (Hons)
A handy tool for tri-state monitoring of logic circuits
M.W. AMPLITUDE MONITOR
by Stef Niewiadomski
Enjoy your listening as you used to through your radios of bygone eras
INGENUITY UNLIMITED – Sharing your ideas with others
CCO Metal Detector; Robo Voice Effects; Visual Capacitance Gauge
SMART KARTS – 2 On Manoeuvers and Software Development
by Owen Bishop
Discussing the first software routines for our PIC-based mobile buggy
760
772
786
782
814
Series and Features
CIRCUIT SURGERY
by Alan Winstanley and Ian Bell
Current Flow; Diode Operation; Zener Diodes
TECHNO TALK
by Andy Emmerson
Digital techniques may revive the voice of Queen Victoria!
PRACTICAL ELECTRONICS 40TH ANNIVERSARY
by John Becker
A brief commemoration of our ancestral sister’s origin
LIGHT EMITTING DIODES – 3 Boosters, Alternative Flashers and
Multicolour L.E.D.s
by Anthony H. Smith, BSc. (Hons)
Continuing our short series enlightening you about l.e.d.s.
PIC N’ MIX
by Andrew Jarvis
Introducing some new PICs to TK3 – the PIC16F87xA Family
FLOATING POINT MATHS FOR PICS
by Malcolm Wiles
How to use floating point maths with PIC16Fx microcontrollers
NET WORK – THE INTERNET PAGE
surfed by Alan Winstanley
Cybersquatting; Typosquatting; Pressure Selling; Domain Slamming
770
780
794
797
804
810
824
Regulars and Services
BACK ISSUE CD-ROMS
single-source shopping for issues you’ve missed
EDITORIAL
NEWS –
Barry Fox highlights technology’s leading edge
Plus everyday news from the world of electronics
READOUT
John Becker addresses general points arising
FREE MICROCHIP ONLINE COMPETITION
Win Microchip Development Tools!
SHOPTALK
with David Barrington
The
essential
guide to component buying for
EPE
projects
PLEASE TAKE NOTE
PIC Magnetometry Logger (July ‘04); Glitch-Free Switching (I/U Oct ‘04);
CD-ROMS FOR ELECTRONICS
A wide range of CD-ROMs for hobbyists, students and engineers
DIRECT BOOK SERVICE
A wide range of technical books available by mail order, plus more CD-ROMs
© Wimborne Publishing Ltd 2004. Copyright in all
drawings, photographs and articles published in
EVERYDAY PRACTICAL ELECTRONICS is fully
protected, and reproduction or imitations in whole or
in part are expressly forbidden.
754
759
767
791
792
803
803
806
821
825
PRINTED CIRCUIT BOARD AND SOFTWARE SERVICE
PCBs for
EPE
projects. Plus
EPE
project software
ADVERTISERS INDEX
828
Our December 2004 issue will be published on
Thursday, 11 November 2004. See page 751 for details
Readers Services
)
Editorial and Advertisement Departments 759
749
Everyday Practical Electronics, November 2004
NEXT MONTH
VERSATILE PIC FLASHER MK2
The original Versatile PIC Flasher (Dec '02) Christmas Star
generated random lighting effects on its various l.e.d.s, with
switches providing a choice of different speeds and modulation
depths.
This article describes four add-on sensor boards which can be
used with the Flasher to control its flashing rate in response to
sound, temperature, light and movement. For example, a
proximity sensor sends the Star into its "shimmer" mode when
someone passes by. You can also talk to the Star, and get a
response – kids love shouting at it to "wake up"!
It is a good "Christmas Time" design, which might even allow
you to suitably light-up Santa!
SUPER VIBRATION SWITCH
This project simulates an old-fashioned vibration
switch in which movement of a flexible lever makes
contact with an electrical terminal. There are three
significant differences, though. First, there is an
indicator light, which shows that vibration has been
detected. Second, the circuit's output is via a relay,
allowing it to be plugged into other circuits having
widely varying supply voltages.
The real difference, however, lies in its sensitivity. It
may justifiably be described as being "super-
sensitive". While the old-fashioned vibration switch is
best suited to detecting noticeable motion, this
design is capable of picking up very subtle vibrations
indeed, depending on its adjustment setting.
It will easily pick up a person walking across a
wooden floor at virtually any distance (e.g. at the far
side of a hall). The author's prototype was capable of
picking up a pin striking a wooden floor at two metres
distance. It reliably picked up a telephone receiver
being put down in the next room!
WIND DIRECTION INDICATOR
Although designed originally for the use of yachtsmen,
this simple wind direction indicator could equally well
find use in an amateur weather monitoring station. The
input device is a modified mechanical shaft encoder
with 4-bit Gray-coded output. The circuit to which this
is attached converts the code to a form suitable for
driving 16 l.e.d.s arranged in a circle, from which the
prevailing wind direction can be seen clearly.
LIGHT DETECTOR
This project makes use of an l.e.d. as a simple light sensor that
generates a photovoltage that varies with light intensity. By
comparing the photovoltage with a variable reference voltage, the
circuit provides a digital output signal that changes state when the
monitored light level crosses a preset threshold.
The detector also provides visual indication by illuminating the
sensor l.e.d. when the light exceeds the preset level. In this way,
the l.e.d. provides a dual function, acting as both the sensor and
the indicator. An optional, optically-isolated output is also available.
NO ONE DOES IT BETTER
DON'T MISS AN
ISSUE – PLACE YOUR
ORDER NOW!
Demand is bound to be high
DECEMBER 2004 ISSUE ON SALE THURSDAY, NOVEMBER 11
Everyday Practical Electronics, November 2004
751
Quasar Electronics Limited
PO Box 6935, Bishops Stortford,
CM23 4WP
Tel: 0870 246 1826
Fax: 0870 460 1045
E-mail: sales@quasarelectronics.com
Add £2.95 P&P to all UK orders or 1st Class Recorded – £4.95.
Next day (insured £250) – £7.95. Europe – £6.95. Rest of World – £9.95
(order online for reduced price UK Postage).
We accept all major credit/debit cards. Make cheques/POs
payable to Quasar Electronics Limited.
Prices include 17.5% VAT. MAIL ORDER ONLY.
Call now for our FREE CATALOGUE with details of over 300
high quality kits, projects, modules and publications.
0871
Helping you make the right connections!
CREDIT CARD
SALES
717 7168
NEW!
DTMF Telephone Relay Switcher
Call your phone number
using a DTMF phone from
anywhere in the world
and remotely turn on/off
any of the 4 relays as
desired. User settable
Security Password, Anti-Tamper, Rings to
Answer, Auto Hang-up and Lockout.
Includes plastic case. 130 x 110 x 30mm.
Power: 12VDC.
Kit Order Code: 3140KT –
£39.95
Assembled Order Code: AS3140 –
£49.95
Serial Port Isolated I/O Module
Computer controlled
8-channel relay
board. 5A mains
rated relay outputs
and 4 opto-isolated
digital inputs (for
monitoring switch
states, etc). Useful in a variety of control
and sensing applications. Programmed via
serial port (use our new Windows interface,
terminal emulator or batch files). Serial
cable can be up to 35m long. Includes
plastic case 130 x 100 x 30mm. Power:
12VDC/500mA.
Kit Order Code: 3108KT –
£54.95
Assembled Order Code: AS3108 –
£64.95
Infra-red RC 12-Channel Relay Board
Control 12 on-board relays
with included infra-red
remote control unit. Toggle
or momentary. 15m+ range.
112 x 122mm.
Supply: 12VDC/0·5A.
Kit Order Code: 3142KT –
£41.95
Assembled Order Code: AS3142 –
£51.95
PC Data Acquisition & Control Unit
Monitor and log a
mixture of analogue
and digital inputs
and control external
devices via the ana-
logue and digital
outputs. Monitor
pressure, tempera-
ture, light intensity, weight, switch state,
movement, relays, etc. with the apropriate
sensors (not supplied). Data can be
processed, stored and the results used to
control devices such as motors, sirens,
relays, servo motors (up to 11) and two
stepper motors.
Features
*
11 Analogue Inputs – 0·5V, 10 bit (5mV/step)
*
16 Digital Inputs – 20V max. Protection 1K in
series, 5·1V Zener
*
1 Analogue Output – 0-2·5V or 0-10V. 8 bit
(20mV/step)
*
8 Digital Outputs – Open collector, 500mA, 33V
max
*
Custom box (140 x 110 x 35mm) with printed
front & rear panels
*
Windows software utilities (3·1 to XP) and
programming examples
*
Supply: 12V DC (Order Code PSU203)
PIC & ATMEL Programmers
We have a wide range of low cost PIC and
ATMEL Programmers. Complete range and
documentation available from our web site.
Programmer Accessories:
40-pin Wide ZIF socket (ZIF40W) £15.00
18VDC Power supply (PSU010) £19.95
Leads: Parallel (LDC136) £4.95 / Serial
(LDC441) £4.95 / USB (LDC644) £2.95
NEW!
USB ‘All-Flash’ PIC Programmer
USB PIC programmer for all
‘Flash’ devices. No external
power supply making it truly
portable. Supplied with box
and Windows Software. ZIF
Socket and USB Plug A-B lead
not incl.
Kit Order Code: 3128KT –
£34.95
Assembled Order Code: AS3128 –
£44.95
Enhanced “PICALL” ISP PIC Programmer
Will program virtually ALL 8
to 40 pin PICs plus certain
ATMEL AVR, SCENIX SX
and EEPROM 24C devices.
Also supports In System
Programming (ISP) for PIC
and ATMEL AVRs. Free software. Blank chip
auto detect for super fast bulk programming.
Requires a 40-pin wide ZIF socket (not
included)
Assembled Order Code: AS3144 –
£54.95
ATMEL 89xxx Programmer
Uses serial port and any
standard terminal comms
program. 4 LEDs display
the status. ZIF sockets
not included. Supply:
16VDC.
Kit Order Code: 3123KT –
£29.95
Assembled Order Code: AS3123 –
£34.95
NEW!
USB & Serial Port PIC Programmer
USB/Serial connection.
Header cable for ICSP. Free
Windows software. See web-
site for PICs supported. ZIF
Socket and USB Plug A-B
lead extra. 18VDC.
Kit Order Code: 3149KT –
£34.95
Assembled Order Code: AS3149 –
£49.95
Introduction to PIC Programming
Go from a complete PIC
beginner to burning your
first PIC and writing your
own code in no time!
Includes a 49-page step-
by-step Tutorial Manual,
Programming Hardware (with LED bench
testing section), Win 3.11–XP Programming
Software (will Program, Read, Verify &
Erase), and a rewritable PIC16F84A that
you can use with different code (4 detailed
examples provided for you to learn from).
Connects to PC parallel port.
Kit Order Code: 3081KT –
£14.95
Assembled Order Code: AS3081 –
£24.95
ABC Maxi AVR Development Board
The ABC Maxi board
has an open architec-
ture design based on
Atmel’s AVR
AT90S8535 RISC
microcontroller and is
ideal for developing new designs.
Features:
8Kb of In-System Programmable Flash
(1000 write/erase cycles)
)
512 bytes
internal SRAM
)
512 bytes EEPROM
)
8 analogue inputs (range 0-5V)
)
4 Opto-isolated Inputs (I/Os are
bi-directional with internal pull-up resistors)
)
Output buffers can sink 20mA current
(direct l.e.d. drive)
)
4 x 12A open drain
MOSFET outputs
)
RS485 network
connector
)
2-16 LCD Connector
)
3·5mm Speaker Phone Jack
)
Supply: 9-12VDC.
The ABC Maxi STARTER PACK includes
one assembled Maxi Board, parallel and
serial cables, and Windows software
CD-ROM featuring an Assembler,
BASIC compiler and in-system
programmer.
Order Code ABCMAXISP –
£79.95
The ABC Maxi boards only can also be
purchased separately at £59.95 each.
Controllers & Loggers
Here are just a few of the controller and data
acquisition and control units we have.
See website for full details. Suitable PSU for
all units: Order Code PSU445 –
£8.95
Rolling Code 4-Channel UHF Remote
State-of-the-Art. High security.
4 channels. Momentary or
latching relay output. Range
up to 40m. Up to 15 TXs can
be learned by one Rx (kit
includes one Tx but more
available separately).
4 indicator LEDs.
Rx: PCB 77x85mm, 12VDC/6mA (standby).
Two & Ten Channel versions also available.
Kit Order Code: 3180KIT –
£41.95
Assembled Order Code: AS3180 –
£49.95
Computer Temperature Data Logger
Serial port 4-channel tem-
perature logger. °C or °F.
Continuously logs up to 4
separate sensors located
200m+ from board. Wide
range of free software appli-
cations for storing/using data.
PCB just 38x38mm. Powered
by PC. Includes one DS1820 sensor and
four header cables.
Kit Order Code: 3145KT –
£19.95
Assembled Order Code: AS3145 –
£26.95
Additional DS1820 Sensors –
£3.95 each
Most items are available in kit form (KT suffix)
or pre-assembled and ready for use (AS prefix).
Kit Order Code: 3093KT –
£69.95
Assembled Order Code: AS3093 –
£99.95

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