We are nearing the step on our first West Coast Drive with 3 CIM shifting gearboxes that will need Encoders. We anticipate some mounding on the corner wheel axles. I’m not a fan of the gearbox bolt on solution mid reduction. If ajlapp would bring to market his encoders all would be solved.
We are looking for some inspiration to how these mounts should look. This is a test chassis so one side is strung up with #35 chain the other is #25H. The #25H side seems to have plenty of space to work around but the #35 chain has less. Oh and another note we are using VersaBlocks so that adds a wrinkle.
What encoder are you using? Our solution this year was similar to 254’s last year. Since we used Versablocks, we utilized the two 10-32 tapped holes to mount our plate, seen here. We both used Mag encoders so it was simple to adjust the standoff length to get the distance from the magnet that we needed. I can get a better picture tomorrow evening.
Yes we where planning to do the same thing but on the #35 side the chain looked like it was going to interfere with the standoff. What size #35 sprockets are you using. We are using the 15t. The 254 chassis uses the the insert blocks with the holes in a better location.
Its mostly educated guessing at this point, but I’m fairly certain my team will also be using a similar solution that attaches to the extra mounting holes of the VersaBlock, specifically the one mentioned in this thread. We’ll be modifying it to the fit the AMT103-V. I plan to workshop it with our kids tomorrow and see how it fits in the CAD.
When using the Mag Encoder, we always make brackets 2" center to center, not a great reason besides it clears everything. We are changing our design slightly to make it better for 3D printing. Typically we drill the holes for the bracket initially when it is machined, but we also created a jig that always lines the axis of wheel in the center of the 2" bolt pattern so we can add the pattern later if need be. We are using 15t #35 sprockets and dont have any clearance issues.
We ran into the same issue with 35-tooth sprockets - the ones we had were too big to utilize the mounting holes like Mike’s picture shows. Instead, we got some Grayhill encoders and made a little mounting bracket so they were attached to our belly pan. We then connected those to the axle using some surgical tubing - turn down the axle to match the encoder shaft diameter, the tubing stretches over each of them and provides a nice flexible coupling. This meant we needed no precision manufacturing for that part, and it didn’t matter if the belly pan flexed a little. Overall, it was very reliable with no issues.
That said, I too would prefer an encoder option that could incorporate a hex through hole. This fall, we’ve played around with the 3D printed solution from the thread the OP linked, and it’s pretty straight forward and functional. Just printing on the team’s Makerbot got something that worked, although the gear teeth weren’t the greatest - I wouldn’t want to put it on a competition robot with it. We’ve been looking at possibly getting a sponsor with a professional 3D printer to make a batch for us that would be higher quality.
Fun fact, you can actually make something very similar to that utilizing the versaplanetary integrated encoder and a 3D printer. We utilized the VP encoder housing / mag encoder with a 3D printed (.5 HEX through hole) replacement internal gear and just bolted the thing to the side of our 2017 shooter. [strike]I tried to find the model or a picture but was not able to find anything quickly. I should be able to get a picture when I visit our shop tonight if you would like to see it. [/strike]
We did not seem to have any issue using it with a PID to control our RPM. YMMV.
I can personally vouch for a similar solution. My students found one designed by team 5406 that has a full mount. It is designed to fit over the .5" hex axle and bolt to the Versablock mounts. We used it with fantastic results last year.