If you want to build Light dimmer that can be controlled from many ways then check out this Network Light Dimmer. This AVR AtMega8-based light dimmer project has multiple control interfaces such an RS485 network, an infrared remote control, a proximity touch slider or touch sensor (Qprox QT401/QT110). Other features including Opto isolated and handle power up to 500watts. The device is powered from the RS485 network connection which has +12, data+, data- and GND.
Sylvain Bissonnette, the designer, said that in this project the MCU Mega8 has many duties: detect zero crossing of phase, calculate the firing angle for the triac, manage the network communications, check for a finger presence and position on the proximity touch slider and detect and decode infrared coming from a remote control.
Multi Controller Light Dimmer
Project Firmware, Schematic and Documentation