This is a control system that uses IR sensors to read black marks made on a rotating paper disk. The disk is currently rotated by a continuous rotation servo controlled by a Raspberry Pi Pico. The IR sensors feed a signal to comparators and then a 555 timer is turned on/off. This 555 timer creates a pulse that is feed into a stepper driver. The speed is controllable by a 100k potentiometer. Another signal is also read by a IR sensor and a comparator sends on that buffered pulse to the direction pin of the stepper. In this way two IR sensors can control both on/off and direction of a single NEMA 17 stepper motor.
I would like to in the near future build out a two motor version, so in this way I can have them as the main drive of a smaller 2 wheel robot.