Controlling 3 stepper motors with an Aduino

SCHEMATIC.pdf (73.7 KB)I am trying to control 3 stepper motors with an Aduino Uno and 3 motor controllers.

The motors will either not turn or only one will turn and the others will not.

Attached is a copy of a schematic and the code I am trying to use.

I don’t know what I am doing wrong could anyone please help.

mymotor3.ino (1.04 KB)


We received an email from you about this problem. Have you tried doing the things we suggested in the email? I have listed them here again:

  1. Simplify your system down to one stepper motor and driver.
  2. Make sure you have your current limits set to an appropriate value.
  3. Place capacitors between the VMOT and GND pins on each of your drivers, as shown on the minimal wiring diagram located on the A4988 product page.
  4. Increase your supply voltage so it is not so close to the minimum operating voltage of the A4988.

I also noticed that it looks like you are supplying 3.3V to the VDD pin on each of your A4988 driver. If you are using 5V logic signals on the STEP and DIR pins, you should also connect VDD to a 5V source.


it seems i may have a power problem
i have installed caps between vmot and gnd on each motor controller.
i cranked up the voltage to 12v.
i connected with just one motor and it ran well once i adjusted the amp limiter on the controller board.
however, when i connected the other 2 motors and control boards it will only vibrate one motor.
my meter while set to 12v drops to 6v ??? so i measured across vmot and gnd on each controller and it was indeed 6v.
is there something going on with the controller boards or the programmer that draws it down like that?


I agree that it sounds like a power issue; I suspect your stepper motors are trying to draw more current than your supply can handle. What are you using for your power supply? With three of those #1206 stepper motors (rated at 0.67 A per phase), you should be using a power supply capable of sourcing just over 4 A (assuming the current limit is set to the rated per phase current).