It’s fully functional and running 🙂
Its getting power over cable to save batterylife and make it easier to test. I resoldered the powerplug to instrument cable plug to make it easier to extend the line.
The white roll is powered by a 540class motor with 30:1 gear-ratio. The black scooterwheel is free running. The metal “roll” are three ballbearings stacked together with a small shim in between. The cable runs over the two bearings. The third bearing functions as a distance holder 🙂
All white metal parts are leftover parts of a ceiling-mount set of a beamer