Here is a motor ... of the circuit is the OS25B10 transmissive optical sensor with phototransistor output (OC1). Next is the venerable LM393 dual comparator chip (IC1) configured as a simple Schmitt ...

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 ...