[Frank Herrmann] had an interesting idea to turn a geared DC ... motor rotation and listen on the ‘stepper motor driver’ interface pins hooked up to the motion controller upstream. The Arduino ...

and some of the ways the wiring in these motors is a little different than a simple two wire DC motor. They also discuss some of their favorite ways to control the motors ranging from a light ...

A note here, adding 100Ω resistors in series with the arduino pins could help limit pin current if someone shorts the motor connections to either rail ... the positive rail can be any dc voltage – ...