By changing a few options on the command line, it’s possible to get ServoBlaster to output PWM signals from 0-100%. By using three channels and connecting these to an RGB LED it’s possible to produce a wide spectrum of colours. Each channel can be given a value, so for instance Red=100%, Green=0% and Blue=100% gives a rather pleasing purple/magenta colour. The circuit is rather simple, although my RGB LED was common-anode, which meant that using a ULN2803 darlington driver seemed a better option compared to a bunch of transistors.
This RGB might become a useful status LED, a sunset simulator or perhaps an interesting weather display, where colours represent the coming weather. There’s plenty of spare capacity for more LEDs in that darlington driver!
The RGB LED can be found here: http://www.rapidonline.com/Electronic-Components/Piranha-Rgb-Led-72-8998
- LED – RGB 5mm Square (Piranha) (sparkfun.com)