[mikets]

The optical encoder comes with a centering tool and a disc spacing tool. If you follow the instructions correctly in using those tools, you should not have any problem. We have a student that did not use those tools when assembling the encoder. He pressed the optical disc all the way down and ended up scratching it. So our autonomous acted strangely. After scratching our heads for a while, I finally pulled out the encoder and examined the disc and found the problem. Once we replaced the disc, everything worked fine.