Re: Is it legal to make a custom slip ring?
 

Jon brings up an interesting point, and it would definitely have to go to Q&A to get a definitive answer. However based on past rulings my guess is they probably wouldn't be huge fans. Also the 4-channel one still gets quite bulky and thus probably not worthwhile.

If they were to ever allow custom slip rings, our team has worked on a design in the past.

You can reference this thread to see the original version we actually built using the CIM brush assemblies from inside the motor.

We later refined the design using the brush assemblies from BAG motors, which made for a much lower weight per module, and much smaller footprint (2" dia. x 2" height). It also integrated an absolute encoder mount for the steering onto the slip ring which was convenient.

Here is the link to the CD thread for that: here

And here is a direct link to an imgur gallery of it: here

While I wish that someday FIRST could make safe custom electrical applications legal, I don't see it happening any time soon.