INTRODUCTIONThis application note describes a Microchip system
solution for a low end/power wireless home security
system. This design implements an HCS200 encoder
for the intruder sensor signal encryption, one
PIC12C508A PICmicro® for sensor monitoring and RF
signal initiation, HCS515 decoders for decrypting the
received intruder sensor signal and a PIC16C77
PICmicro for base station panel monitoring and control.
Other support logic is included, such as a battery
back-up circuit, simple single stage lead acid battery
charger and external siren control, but the focus of the
application is the implementation of Microchip
KEELOQ® and PICmicro products for a complete solution.
for detail follow the link
http://ww1.microchip.com/downloads/en/AppNotes/00714a.pdfthis security sysytem is very good but further modifications can be done in it like adding GSM pohone for communication using AT commands, motion sensor, fire sensor etc. i will try to post further modification and suggestion to this under same heading soon, may be you like it.
thanx for reading