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Stepper test rig


#1

Gentlemen, I need to configure a stepper motor drive with manual control (potentiometer) to analyze the performance of various steppers for a 3d printer extruder. I have an Arduino Uno, along with a A4988 driver and a few steppers which I purchased from Pololu. I have found a schematic at Arduino pololu.com/picture/view/0J3360 . I would appreciate some help or maybe point me to previously documented info for the wiring. Thanks


#2

Hello.

The tutorial you linked to on Arduino’s website does not apply to our A4988 carrier since the tutorial just uses H-bridges, which makes control more complicated. You should refer to the wiring diagram you linked to on our website; it is our recommended minimal wiring diagram for our A4988 carrier. If you need help getting started, you might find this guide posted by decrDude on our forum helpful. You could also look at this blog post with a video we made about how to set the current limit on our driver carriers.

I also recommend breaking your project into smaller parts. I would recommend getting the stepper motor to move and read the analog signal separately, and combining those things when you have each part working on its own.

- Grant


#3

Thanks Grant, Although I am anxious the get this rig operational so I can move on to the task at hand I do need to have a better fundamental understanding so I will take your advice on getting the stepper to operate without the pot. I did spend some time over the weekend reading up on the driver including how to set it for a particular motor.
I do have a couple of questions relating to this diagram pololu.com/picture/view/0J3360
1- A 100uf cap is shown. What cap rating voltage? does it matter? Im assuming this is an electrolytic cap? this is the PS I am using amazon.co.uk/Pro-Peak-Power- … B000OZQ44W
2- where exactly does STEP and DIR from the driver go on my Uno? Edit- I found this info


#4

The voltage rating on your capacitor is the maximum voltage that can be applied to the capacitor. You should use an electrolytic capacitor that has a voltage rating greater than the voltage of your power supply.

- Grant