We’ve had fun with the sensors in optical mice before, but [Mac Cody] wrote in to tell us about his legitimate application of the technology. First, he disassembled the mouse and bypassed the on-board controller. He then wired the clock and data lines to a Harris RTXEB single board computer. It’s based around a Harris RTX2001A microcontroller which he programmed in Forth to talk to the Agilent optical mouse sensor. Documented code is provided in case you want to implement it in a different language. His future plans for the system are to roll it into some robot projects for dead reckoning navigation.