[eugenebrooks]

We used banner sensors this past season, looking through slots at reflective tape strips put on the black rims of the kit wheels. The light/dark transitions were tracked in the fast loop and the RC was capable of keeping track of the pulses. The only real issue is the possibility of missing pulses while "not" in the fast loop, and if this is a problem, use a timer interrupt fast enough never to miss a transition. This was never a problem for us in practice, but you could demonstrate the issue in high speed with the robot free-wheeling on blocks. We put 72 strips on the wheel rim, providing 144 transitions, or 2.5 degree resolution for wheel rotation. This was about 1/4" on the floor. I have posted the code that supported the sensors in the past, and it can be found in the archives.