In a robot arm, small accuracy errors at the base ... You could build a servo out of junk DC motors with a “3 cent” microcontroller, then.

Raspberry Pi HATs offer small, stackable data acquisition with features like analog and digital I/O.

[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 ...

At MD&M West 2025, Henry Kim, a regional sales engineer at Harmonic Drive, demonstrated advancements in actuator design.