Two smaller projects are also part of the whole automation system. Both of these devices communicate with the base station over the 868 MHz radio link, with an RFM12 radio transceiver.

Project 1: A small energy efficient sensor node.

This is small temperature sensor based on an Attiny45 IC and a 10k NTC resistor. It will send out an update every 150 seconds and sleep inbetween. Powered by a CR2032 coin cell, it should last for a about 6-12 months.

Project 2: A remote controlled RGB light

This light is based on a cheap 3 Watt RGB LED from dealextreme, controlled by an Attiny44. Via the radio you can select individual colours as well as simple fade and strobe effects.