This prize-winning circuit from our Flash Micro Competition responds to a drive signal containing RGB (red/green/blue) values by making a multi-colour LED produce the desired hue. The circuit doubles as a converter between colour coding systems.This entry received for our Flash Micro Competition (see the January 2003 issue) demonstrates that complex peripherals like a D/A converter are not really necessary when it comes to controlling a three-colour LED. Here, a microcontroller from the 80Cxx series handles all functions necessary to enable such an LED to produce all possible colours.