On the Wheel Watcher encoder (rb-sbo-33) what is the size of the center hole. I was looking to use this to monitor rotation of my robot. I am using a motor with a 6 mm shaft and wondered if this would fit.
The center of the disk is 1cm (10mm) in diameter. You could likely print your own encoder wheel and adhere it to something with a hard back (like a plastic lid) and cut it to size. The expensive part are the electronics after all.