Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software.

arduino.cc

I’ve owned an Arduino Duemilanove board since Summer 2009.

Arduinos talking:

• Video
• Forum lusorobotica.com

Arduino library to read values from quadratic rotary encoders.

• Example encoder
• Schematic connections
• Library page

Arduino pins used by different shields list.