Detects and alerts if any of the monitored modules goes silent; meaning their heartbeat stops. Uses an AVR AT90S8515 microcontroller.
Electric heater and timer controller — AVR

Controls an electric heater, and has a simple 15 minutes timer. Uses an AVR AT90S2313 microcontroller.
Multi-purpose AVR module

Monitors the Rack box status panel, IR sensor, porch door and turns off lights. Uses an AVR ATtiny2313 microcontroller.
Multiplexer output extender

Get more digital outputs on your I/O device with a multiplexer, 3 outputs turned into 7.
Sound alarm control unit — AVR module

Simple unit to control three sound signals; beep, siren and buzzer. Uses an AVR ATtiny2313 microcontroller.