Encoder for VEX Single Speed, Single Reduction gearbox

All right, I was trying to avoid this post. I am loving all the great new VEX products, but has anyone come up with a clean way to get the typical US Digital Quadrature optical encoders onto the subject gearboxes?

A student tried making an adapter on the lathe but it turned out to be too troublesome getting the tolerances right. We were thinking shaft collars and shafts, but alas, nothing available really seem fit there either. Bottom line is even if you can extend the shaft in a way the ring fits, then you have to mount the encoder assembly, down in the center of the gearbox, a really hard place to work between the motors.

Are there solutions, I am sure (feel free to share :confused: ). But I think we have wasted enough time at this point trying to build one. So I guess we are going to cut our loses and order some Grayhills. Overall I love what VEX has done, but the US Digital encoder is so popular I really wish they had accommodated for it as well. Is it just us or has anyone else ‘lost some sleep’ over this one?


US Digital offers a pretty huge kit encoder that you can get with a 1/2" through bore: E3 Kit Encoder. You could probably mount that to the face of the gearbox and use whatever shaft is left afterwards. It’s 0.615 thick, so it’d eat up a decent bit of of your shaft.

Thanks Kevin
We ended up biting the bullet and ordered 2 of the Greyhill units referenced in the Vex documentation, along with the shaft adapters. More expensive than the US Digital units that used to be in the KOP, but they integrated very cleanly with the Vex transmission.

We’re planning on using these from FIRST Choice. We think we can modify the encoder mount to accommodate these easily.