Stepper driver: How to limit current with no pot?

I want to control a stepper motor, and I decided to try the DRV8825. I ended up getting this card: Stepper_Motor_Shield_For_Arduino_DRV8825__SKU_DRI0023-DFRobot
I also got this (Just to reach free shipping): SilentStepStick TMC5160 Stepper motor driver - Watterott electronic

None of them have a pot to limit the current. And every guide explains limiting with a pot.
What are my options? (Using a Uno if that matters)

If the board in the first link has DRV8825 drivers then they should have preset potentiometers that you adjust with a small screwdriver. If you want more help take a close-up photo of one of the drivers and post the photo in your next Post. See this Simple Image Posting Guide

The driver in your second link is configured using instructions sent to it using SPI but I don't have any personal experience with them.


It does use DRV8825 but there are no pot. Others are asking too:

I will put the TMC and SPI aside until later, enough to get the basic stuff up and running.

You need that pot. The schematic for the DRV8825 shows "Rx" and "Ry" in its place, so look for pads on the circuit board. Maybe you are supposed to add your own.

I recommend to buy parts like that from Pololu, because the things Pololu engineers design, build and sell actually do work.

It seems to be fixed at 1.6Amp. No idea if I can solder or connect a pot somewhere here...
Sure getting the next directly from Pololu.

It seems to be fixed at 1.6Amp

That is an incredibly stupid design decision.

I would send that piece of junk back. Microstepping does not work properly if the driver does not actively limit the current, and the designer decided not to give you control over that, to save a couple of pennies.

Did you look under the stick-on heat sinks?

No idea what they were thinking! But it sure look stupid. I have pulled off the driver boards to check, but nok taken off the heat sinks. I can try to pull them off....

Just did, and no pot...

Just get a bunch of DRV8825 modules and replace the ones that have no adjustment (they are
socketed aren't they?). DRV8825's are cheap (I advise to get a few spares while you are at it).

This topic was automatically closed 120 days after the last reply. New replies are no longer allowed.