[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 ...

[ZeroBacklash] created a little strain wave gearbox (harmonic drive) for when you want to trade speed for torque on NEMA 17 stepper motors. Strain wave gears work by deforming a stationary ...