Projects in the April 2002 issue of EPE Magazine

PIC Controlled Intruder Alarm
- a powerful and sophisticated system with features too numerous to list here! Our new burglar alarm design has everything you would expect of a commercial system - eight zones, exit/ entry delays, bell timer, PIN code, keypad, battery backup, LCD display, tamperproof system, and more besides! Get secure — build our new system now! Free source code available from our FTP site.

In Feb. 2003 issue wesaid a revised PIC software in a which an entry/ exit zone bug has been fixed is on the FTP site and EPE Disk 5.
Stepper Motor Controller
- a simple but highly effective way of controlling 4-phase stepper motor positioning manually, using a rotary switch. Enables you to operate a wide range of mechanisms - great for robotics and control applications! Bidirection operation, end-of-travel detection via magnetic reed switch. Full details of stepper motor adaptation are included.
Solar Charge & Go for mobile phone batteries. Our solar-boosted unit provides a back-up supply and helps keep your mobile topped up. Charges a 2.4V or 3.6V NiCd or NiMH battery (not tested or suited to LiOn or other types or voltages). Just the thing for backpackers, vacations, campers, it can also power 3V Walkman-type units for short periods.
Electric Guitar Tuner
- always a popular project amongst musicians, our latest Guitar Tuner project is very straightforward to build and uses a simple flashing l.e.d. to indicate the difference between the guitar's frequency and the target frequency. When the l.e.d. stops flashing, the correct note has been tuned. (Separate reference frequencies are needed for initial set-up.) Battery operation, ideal for inexperienced constructors. Build this design now and stay in tune!
Teach-In 2002 (6) - Magnetic Sensors, Interference and Noise. Our team of Teach-In tutors continues our ten part series Making Sense of the Real World, this month looking at Hall Effect sensors, reed switches and the start of a simple wind rotation sensor (anemometer). Plenty of theory and practical work is included.

Also in this issue - Programming PIC Interrupts (2) - the concluding installment of our mini series detailing the techniques to use Interrupts successfully with your PIC programs. Circuit Surgery - the perils of testing with grounded power supplies. Ingenuity Unlimited - more readers' ideas. New Technology Update on the latest FinFET devices. Interface - PC serial port interfacing. Review - Electronic Principles V7 CD ROM. Free op.amp wallchart in this issue.