Adding voltage to an electric motor will increase its speed ... but a flat spot is milled on either side of the shaft in order to provide a sort of keyway to keep the stator from spinning.

A quadrature encoder provides a way to let hardware read movement (and direction) of a shaft, and they can be simple, ...

Slide the two together, and the result is a far sturdier solution than trying to mate a 3D printed gear directly to a motor shaft with a friction fit or a screw. This solution isn’t necessarily ...