RGB Led strip power and color color using a PS2 trackball and an Arduino

This prototype will be used in a french science exhibit about light (2015 is the UN international year of light)


Project on breadboard is easy to build,

Schematic is clean and Arduino pcb shield designed and routed but untested (should work)


I actually use 2N2222 transistors because it's a small part (60 cm) of the led strip.

If you want to drive a full led strip, use bigger transistor like TIP102 instead and a suitable power supply.

I use a MBI38 - ps2 trackball from megatron

datasheet here

All is powered using a 12VDC external power supply.


Arduino code is based on libraries for trackball and color conversion from http://playground.arduino.cc/ComponentLib/Ps2mouse


HSV model is used to control the color


Information on HSV color wheel :



S (saturation) is fixed to 1

and X & Y trackball axis are H (hue) and V (value)


Arduino code (Github) - Code under WTFPL License

Lionel D. for Science-Animation - 2015