The purple boards slotted into the pairs of SIL headers are Pololu Stepper motor drivers. Going this route makes replacing a burnt out chip as easy as plugging in a new module. The terminal block ...

So a DSLR camera was hooked up to my test electronics — an Arduino ... by the motor’s slight detent torque. The Texas Instruments DRV8825 on a Pololu-like stepper driver breakout board ...

grbl is stepper motor controller ... that are too powerful for the normal drivers included on grbl Arduino shields (or integrated Arduino+drivers equivalents), and so I have been considering designing ...