RGB LED DIY Stair Lighting using an Arduino Uno and TLC5940 chips

Mike Szczys from Hack a Day shares a hack that he found by Geert on his Just a Thought blog. Geert wanted to jazz up his stairs but adding some DIY RGB LED stair lighting. He used an Arduino Uno for the brain and some TI TLC5940 chips to do the heavy lifting of doing the PWM (pulse width modulation) for all of the channels of LEDs.
“We need a lot of PWM controllers. With 12 steps, 3 colours per step, we need 36 PWM channels. My Arduino Uno only has 6 of them, so that’s not an option. Texas Intruments has a solution: TLC5940, a 16 channel PWM unit with 12 bit duty cycle control. It has a serial input, and can be daisy chained to create even more channels. In this case, I need 3. Luckily there is a library for this chip in the  Arduino Playground”