Has anyone checked out the VEX pamphlets lying around their local Radio Shack? According to the brochures, among the inexpensive new sensors coming out for their VEX robots wil be a 100 pulse/rev optical encoder(#276-2156) good for up to 1020 rpm, or about 1700 pulses/sec. While 100 ppr isn't great, it should be good for 1/8" resolution even on the fastest robots if geared correctly. At $
20 for a pack of 2, they're certainly worth a look. They have some other interesting sensors (ultrasonic, line follower kit, etc.) as well. (No, I don't work there, but as a kid, all my paper route money ended up there!
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