Wireless
Monitoring System (Part One)
-a low-cost radio linked short-range data logging
and monitoring system. This incredibly versatile design uses pre-aligned
and UK Home Office approved 418MHz a.m. radio transmitter modules. Can
be used with very wide variety of analogue and digital sensors for environmental,
security or sampling uses and lots more besides! A Windows®3.1/ W95+
PC is used to display recorded data. Full constructional details of the
transmitters and receiver will be given - the system is PIC 16C71 based
and a small degree of surface-mount hand soldering is required. An excellent
home or laboratory project for the more experienced constructor. Source
codes available free from the EPE FTP site here.
In the April
1999 issue a correction was published in respect of the transmitter printed
circuit board layout. Figs. 4 and 6: on the circuit diagram capacitor
C3 should be connected on the other side of the resistor R5 nearest the
PIC. The p.c.b. foil layout contained an error and has been changed: please
refer to the April 99 issue for details.
Light
Alarm- this simple pocket-sized constructional project is a light-activated alarm which offers protection to cupboards and closets, lockers, suitcases, trunks and more. Easy to build, battery operated and fully self contained, this is an ideal project for beginners.
PIC
MIDI Pedal- a PIC-controlled effects unit which adds sustain and glissando to your MIDI line-up easily and inexpensively. Very simple to build on the stripboard design, and battery powered for total portability (below).
PhizzyB
Computers (4)
Our really exciting electronics and computing project combines PC software
and hardware in a unique way to teach you the principles of computer operation.
The PhizzyB Computer Simulator now gains two more input boards to demonstrate
polling and interrupts -see images below. The interrupt board will be
fitted to the PhizzyBot motorised platform (next month) and can be used
for collision sensing, light detection etc. Don't miss our next installment
of this unique series!
Please note,
the PhizzyB hardware is now almost obsolete, with few kits or MCU chips
remaining. Please check all parts are available before commencing construction.
Also in the February 1999 issue - "Scolar Power" - in a special feature, Terry de Vaux-Balbirnie outlines the Government's latest solar power initiatives. New Technology Update - this authoritative column describes MESFETs, PHEMTs and HBTs together with the latest r.f. semiconductor techniques for cellular phones. Circuit Surgery - a look at electret microphones, and PCB facilities in Singapore - can you help? Techniques - Actually Doing It - Robert Penfold tells you how to get it working when it doesn't! Ingenuity Unlimited, Readout and all the regulars in another unmissable edition of your favourite electronics magazine!