PIC Burglar Alarm
The project uses a PIC16C84 to monitor 4 NC alarm inputs that when triggered, activates an output relay. The first zone triggered is illuminated with a solid lit LED, while the second and subsequent zones are indicated with a flashing LED.This project serves as a complete, although relatively basic introduction to digital electronics, PIC microprocessor programming and interfacing techniques.
   PIC Burglar Alarm
More detail on PIC Burglar Alarm website
www.shucksmith.co.uk