My first idea was to have a system vaguely like Bridgeport mill dials. There would be a ring with scribed markings on it which could be rotated and locked down by another threaded ring. Here’s what the parts look like: A simple aluminum handwheel, with a solid stainless steel handle press fit into it. I really don’t like the type with freely rotating handles – if there’s any slop they feel cheap.
Make a robot friend with Adafruit’s CRICKIT – A Creative Robotics & Interactive Construction Kit. It’s an add-on to our popular Circuit Playground Express, FEATHER and other platforms to make and program robots with CircuitPython, MakeCode, and Arduino. Start controlling motors, servos, solenoids. You also get signal pins, capacitive touch sensors, a NeoPixel driver and amplified speaker output. It complements & extends your boards so you can still use all the goodies on the microcontroller, now you have a robotics playground as well.