grbl is stepper motor controller ... for the normal drivers included on grbl Arduino shields (or integrated Arduino+drivers equivalents), and so I have been considering designing my own to link to ...

control the motor rotation and listen on the ‘stepper motor driver’ interface pins hooked up to the motion controller upstream. The Arduino source for this can be found on the project GitHub.

The solution is named Ethersweep, and is a small PCB stack that sits on the rear of the common NEMA17-format stepper motor ... with Arduino covering the firmware and host control side in python.