He was hoping for a drop-in solution using an off-the-shelf trackball, but alas, finding one with the needed features that fit a standard American 2-1/4″ (57.3 mm) billiard ball. Besides ...

A 3D printed mirror mount attaches a first surface mirror to the motor’s shaft and features two levers with a length of 100 mm each for loading the motor with a given mass. For the load ...