The RGBLED and mRGBLED controllers allow you to control the color of RGBLEDs. This might sound trivial, but it actually takes a lot of resources to let you be able to set an RGBLED to any color you'd like. In addition to just lighting an LED up with a given color, these boards also let you install a color or setup transition/animations effects. They are easily controller via an RS232 connection (serial port) or an SPI connection (logic level).

The boards can be built reasonably inexpensively and there are PC boards available for either model. All source code for the onboard PIC processor as well as the software for configuring and using the controllers is available. The protocol is a simple protocol well documented.

There are two versions of the controller -- the original RGBLED controller and the new mRGBLED controller. They both share 90% of the same firmware (only the hardware bits are different).