An charlieplexed array of 20 led's driven by a ATTiny 45/85. This project is used in Alicia Gibb's book 'Building Open Source Hardware'

How to control 20 led's with just 5 pins? Use Charlieplexing. With the use of switching polarity, more pins can be controlled by less pins. This sketch is made, to create 'snowfalls' or shooting star effects. Or just to learn and practice. ;) Thanks to Strykeroz from the Arduino Forum.

Be sure to watch te youtube movie al well. (external links at the side)