How to Solve the Problem of Stepper motor only turning in one direction Answered
I've finally had the time to start putting together the electronics package for a CNC machine, and already need to do some debugging. ;)
I'm trying to get one stepper motor going with the v2.58 board, a RPi 3, Popolu DRV8825, and one of these stepper motors.
I've used the Pololu FAQs to tell me how to hook up the stepper to the RPi CNC board. On my stepper motor A is black, C is green, B is red, and D is blue. I'm getting this from examining the documentation that came with the stepper motor, and I used an LED to verify which wires were connected to each other. I examined the traces on the underside of the board to tell me how things connected to the stepper driver through the screw terminals. The green connector should go to 2B, 1B, 1A, and 2A in that order if you're looking directly at them.
I can get the stepper to turn in one direction, but not the other. It acts like it's trying to move by jerking around, but doesn't actually start turning. If I move it in the other direction there's some jerkiness at the beginning, but it'll start spinning, jerk a bit more near the end, and stop. I've put a short video of this on YouTube.
I've tried using another stepper driver, and gotten the same results. I've tried various different wiring options, but all I've managed to do is change the direction of the issue. I've also tried moving everything over to the Y-axis, and gotten the same result. I'm convinced this is something to do with my stepper motor wiring, but I'm needing some help on figuring out the right way to do it.