Motoron M3S256 + Arduino Uno Power


The voltage I’m looking to deliver to the Motoron M3S256 is the same 5V I’m delivering to my Arduino Uno. Is it possible to power the Motoron M3S256 by delivering power through the DC barrel jack in the Arduino Uno? Or is the only way to power both boards to feed my battery power into the motor power terminals on the Motoron, and then follow the instruction guide for powering Arduino VIN from Motoron VM?

Essentially trying to see if I can use the barrel jack 5V wall adapter I have to power my boards while testing, or if I should just stick to the script of powering 1st Motoron → 2nd Arduino.

Thank you!


We generally recommend powering the Arduino through the Motoron and not the other way around since the VIN and GND connections on the Motoron are designed to handle the current draw from the motors, while the traces and connections for the Arduino’s VIN pin are not (e.g. the Motoron can supply 2A to each of the motors, 6A in total, and the header pins are only rated for 3A).

By the way, please note that the recommended operating voltage for the Arduino Uno is between 7V and 12V, so you might run into problems powering it from 5V through the barrel jack or VIN pin, especially if the voltage dips when the motors are running.


Hi! Thank you for your help, and for the note about the Uno power. I will be using a different microcontroller in the long run that will be compatible with my 5V battery, but for now I’m just trying to get this up and running w/ the basic tutorials.

I have the motor driver on top of my Uno and am delivering power to the designated motor power terminals. I followed the user’s guide to powering the Arduino’s VIN from VM on a Motoron M3S256 or M2S. When providing 7V to the Motoron with 1X low current hobby motor connected + running the Simple example code, nothing happens.

I did set the I2C address per the users guide. I see the red error light is illuminated on the Motoron board, and tried to run the Careful example to see any error codes. The serial monitor keeps returning “Communication Error: 2”, which I’m not really finding a simple way to diagnose what that means/how to fix that.

Are there any solutions / next steps you would suggest for trouble shooting this? Thank you!

That communication error comes from Wire.endTransmission(); a returned value of 2 means “received NACK on transmit of address” (i.e. the Arduino is not getting any acknowledgment back from the Motoron).

You mentioned changing the I2C address; what did you change it to and was there a particular reason you changed it? Most of our examples (including Simple and Careful) use the default address of 16. So if you changed it to something else, you will either need to change it back to the default (which I generally recommend) or modify the examples to specify the new address. Could you try doing either of those and see if that fixes the problem? If you need help changing the I2C address back or making the modification to the example, please let me know.


Thank you so much, I totally skipped over that very important line in the user guide telling me that all the examples use 16 address. It’s working now, thanks for pointing me in the right direction!

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