I was referring to the sensor. The steppers will likely be controlled via PWM signal or maybe just GPIO depending what Ranjib does. Using the drv8825 it's easy to connect to a Pi.Not directly, steppers are usually controlled by a few configuration pins (enable, microstep select, etc) and pulses on the STEP pin.
I'm happy to collaborate on a simple USB to stepper control firmware (or USB to X). Got a partial reel of SAMD11s which would be plenty of horsepower for this sort of glue.