[Al Skierkiewicz]

Wildstang Team #111 used wheel encoders. Very simple solution, a simple cut wheel insert made of aluminum and backed with black paper became the encoder. Used two optical sensors, since they were unlimited under the parts list. Resolution, less than 2 inches, if the wheel stayed on the ground. Two sensors give both tach and direction, when phased 90 degrees apart. Used for auto mode and with accumulated errors during a 15 sec auto mode, we were consistently accurate to within +/- 6 inches anywhere on the field. Our experience was gained from Lego League and testing. We will use this again if the game warrants it.