Multiple stepper motors

Hi everyone,

I am interested on creating a grid of 3x3 (total of 9) stepper motors and controlling them separately. I have successfully tried to control one stepper motor such as in this example.

https://learn.adafruit.com/adafruit-arduino-lesson-16-stepper-motors/parts

Is there somewhere I can read more to make this happen or get advice to control multiple stepper motors from one Arduino Uno board.

All help is appreciated.

Very best, Per

Are you planning to use 28BYJ stepper motors as in the Adafruit demo?

One problem is that each ULN2003 will require 4 connections to your Arduino so a total of 36 connections. That means you will need a Mega rather than an Uno.

Another issue will be the speed at which you want the motors to move, If you need high speeds you will need to calculate whether a 16MHz Arduino can work fast enough. And there is more work for the Arduino when controlling one of those motors compared to a bipolar motor that can use a specialized stepper driver such as a Pololu A4988.

And, you cannot possibly power 9 motors from the Arduino’s 5v pin. Indeed I would not even power 1 motor from it. You will need a suitable power supply for the motors.

You will also need to consider whether you want the motors to move {a} one at a time {b} two or more at the same time or {c} two or more at the same time and in a closely coordinated way so that they all finish their moves at the same time.

Have a look at the AccelStepper library. It is much more advanced than the standard Stepper library and will make the programming easier - but it is not intended for {c}.

…R
These links may be of interest but they are not written for the 28BYJ motors
Stepper Motor Basics
Simple Stepper Code

Robin2: ... These links may be of interest but they are not written for the 28BYJ motors Stepper Motor Basics Simple Stepper Code

The the 28byj-48 can easily be wired as a bipolar motor, by simply grounding the common (red) wire.

ChrisTenone: The the 28byj-48 can easily be wired as a bipolar motor, by simply grounding the common (red) wire.

I am certainly no expert on this stuff but I have always understood that a stepper driver like an A4988 expects the two coils to be electrically isolated for its current limiting to work. Am I wrong?

...R

Hi, To convert to bipolar the common connection has to be removerd.

http://diy3dtech.com/converting-a-28byj-48-stepper-motor-to-bipolar-format/

Tom... :)

The 28byj-48 will work as a bipolar motor without cutting the common connection. I have done this multiple times, and I am sure it works. (I have also modded the motors - it’s a simple operation: pry, scratch and glue.) It is less efficient without severing the common - drawing about 300+ ma when running. When you cut the common wire, it uses less than 200ma by comparison.

The max speed, and apparent torque are the same.

By the way, I drive 28byj-48 motor with 6 volts for best performance, using a tb6612, or a good ol’ l293d. Since it’s not efficient anyway, these older h-bridge chips are fine. A chopper driver is kind of overkill for such a small motor. The A4988 doesn’t match the voltage requirement of the motor anyway.

ChrisTenone: A chopper driver is kind of overkill for such a small motor. The A4988 doesn't match the voltage requirement of the motor anyway.

And I suspect the A4988 would only work if you separated the coils - all of which is why I said in Reply #1 that my links were not written for 28BYJ motors.

By the way, if it could be made to work the voltage would not be an obstacle as you can adjust the A4988 to limit the current.

...R