Showing the turntable and its connection to the power station. A friction drive is used at both ends. On the power station end, the coils around the gree TinkerToy stick give it enough tension to turn. But the coils move from "walk" slowly along the stick so there is a limit on how far it can turn in each direction.
A top view. The string goes around the turntable twice so that it generates enough friction. But it is not tied to the rotating part.