I use an arduino mega2560 with ramps and a4988 driver plus a nema17 stepper motor.

My problem is that sometimes without changing value of direction pin, the direction of stepper changes.

And my other problem is that for example when I make a code to turn 90degrees then delay it sometimes turns about 80degrees and sometimes turns about 100degrees.


What should i do to correct these problems???

oh!!! come on please...
no one knows about my problem.

It sounds like you have a stepper driver issue. Did you adjust the voltage of the drivers? Are there any bridged solder joints?

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