509Px-Diamond Mainboard
Semitone is a cool open dimmer project –

The aim of this project is the development of comfortable standalone digital light dimmers for home use, which are inexpensive, easy to build, yet very feature-rich and configurable. All development details, such as the microcontroller operating systems (firmware), schematics, and documentation, are freely available under the GNU license.

Semitone – open dimmer project – Link.