Finally, the knob on the right could reasonably be thought to be a rotary encoder, but it’s actually connected to a small DC motor.

By stacking some small PCBs behind the motor body, it was possible to squeeze a DRV8837 DC motor driver and a pair of hall effect sensors on the first PCB layer, with the magnetic encoder nestled ...

This Design Idea combines a simple ISA-bus-resident interface circuit; a garden-variety PC; a high-resolution optical shaft encoder; and a PWM-controlled, 0.05-hp, brushed, permanent-magnet dc motor ...