trying to make a system where one master Arduino makes moving 9 steppers 28BYJ-48 by 3 stepper on each slave arduino.

While all the parts on their way to me, wonder to check with professionals.

Maybe I've missed something?

Any suggestions and tips are welcome. Thank you.

Sketch Scheme

2 Answers 2


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I think your schematic might be wrong there. Only one MEGA is connected to a positive side of a battery.

The MEGA can only run on 7V to 12V. BUT PLEASE DO NOT apply the voltage to the 3V3 or 5V pin.

Microcontroller ATmega1280
Operating Voltage   5V
Input Voltage (recommended) 7-12V
Input Voltage (limits)  6-20V

And also, I would only put in another MEGA when you don't have enough I/O pins.

Digital I/O Pins    54 (of which 15 provide PWM output)

In theory you could use 13 steppers on one MEGA. Try slowly scaling up. You don't need PWM for steppers, maybe you're confused with servo's?

And why not use one of the stepper-driving MEGA's as the master? (In the first picture, slave 1 isn't even connected to the SDA/SCL lines of the I2C bus.


I don't quite understand the problem. A arduino mega would have no problem controlling 9 of these steppers alone. If you are asking about i2c protocol please be more specific about what you need help with.

  • How much does she more can handle? Can you point me, how it possible, because as my newbie brain think when one stepper requires 4 PWM outputs and mega has only 15, I can drive only 3. Thank you for your help! Commented Mar 19, 2016 at 13:58
  • These steppers doesn't require any timers really, you can control them with 4 outputs each and control each stepper in code.
    – Hans Neve
    Commented Mar 19, 2016 at 14:00
  • Well, 4 pwm outputs, 15 ppm on each arduino. Commented Mar 19, 2016 at 14:09
  • Why would you need PWM? It's not like doing micro-stepping on a 28BYJ-48 is useful?
    – Gerben
    Commented Mar 19, 2016 at 14:31
  • If you were to tell us what this system of yours is going to do, we might be of more help.
    – Hans Neve
    Commented Mar 19, 2016 at 14:47

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