During the course of building the laser project i looked into using PIC microcontrollers to perform functions that would otherwise be very difficult to achieve with discrete electronics. I came across a site that had a design for a LED light that fitted into a standard MR16 halogen downlighter shell as shown below.

This was my first dabbling in to the world of microcontrollers. My first action was to modify the original program to give much more saturated colours, then I modified the PCB layout so that it would fit into the much smaller MR11 size whilst maintaining the same number of LEDs and adding a handy connector. 

PCB Layout

 

The board is single sided, but be aware that some parts are soldered on from the reverse side. The LEDs are put through the holes and soldered in the usual fasion, but the resistors and connector are soldered on the same side as the tracks. Beware also LED orientation, different manufacturers use different conventions. The calculation of resistor values depends on the supply voltage, LED forward voltage and desired current. The red LEDs have a lower forward voltage and so are in single series string, the blue and green are in two strings of two.

Downloads:

Download Eagle Files

Six of these units were installed in our basement which is my brother's studio