[Frank Herrmann] had an interesting idea to turn a geared DC motor into a servo motor assembly, but with a stepper motor-like interface. By stacking some small PCBs behind the motor body, it was ...

An orrery is a beautiful type of mechanical contrivance, built to demonstrate the motion of heavenly objects. LEGO happens to offer just such a device, built using its Technic line of blocks, shafts, ...