I'll assume you are using the toughboxes. In that case, I have an answer.
You need to either buy or make an encoder mount.
AM sells them, as well as the encoders.
On the tough box, under the motor to the side, there is an extension from the output shaft. There are two holes on the sides of that, this is where you mount the mount plate to. Take a look at the mount and you should get an idea. Be careful with the spinning pattern piece (name?), as if you're not careful you can scrape the pattern right off. On an unrelated note, anyone got an extra encoder plate?
But making your own is simple, making one took me a few hours, but only because I didn't have a small enough drill bit (1/16 I think) to drill the holes for the encoder screws. I ended up swapping the bolts out for slightly larger ones and putting a bolt on the other side.
It's a hack, but that's the way we work on 1244
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