By deconstructing and analysing a typical optical mouse, Conor Peterson has converted it into a very simple camera. This is accomplished with some light soldering, an Arduino board, and some Processing code at the PC side of things. Conor has detailed the process well in this video:
Quite ingenious - and unsurprising considering what can be accomplished with an Arduino-style board, some research and imagination. For those getting started with Arduino, consider our range of hardware including the Freetronics Eleven, the Arduino Uno-compatible board with onboard prototyping space:
Fore more information and the required code, visit Conor's blog.