[Mark McLeod]

We used the optical sensors, but on part of the drive train nearer the motors than the wheels. It kept them inboard and well protected.

We originally used them for counting wheel rotations, but our wheels would spin too much on the ramp especially when going over the top at full speed when the wheels tended to come off the ramp altogether. We didn't have time to implement a custom processor so while accuracy was +/-3" at slower speeds it went to +/- 6-9" at higher speed.

They were very useful to detect stall conditions during autonomous, so if the robot was pushing against an immovable object like another robot, it would do avoidance maneuvers like backing up moving over and trying again. Whenever it was caught in a robot crunch at the top of the ramp it always worked its' way out by the end of autonomous.