Quick question: D.C. Power and motor controllers

Question

Hello element 14 community! Thank you for taking the time to view my question.

So I have a legit arduino mega controlling 3, dual motor drivers. Specifically two sabertooth2x12's and one L298N circuit board. So far I have wired the saberteeth in a pwm control mode, so one wire per motor and a ground wire. That's two ground pins taken on the mega, which is no big deal but my L298N also needs a ground pin. I was wondering if since all three motor drivers are running of the same battery and two of the three driver are grounded, that if the last motor driver (L298N) actually needs to connected to another ground pin on the arduino. Could the circuit still work if only one driver was connected to arduino? Even more like my current setup -- two out of three drivers.

Thank you!!!

P.S - the arduino is going to be running off a separate power source

Robert Peter Oakes · Answer

All the grounds should be going to the same point. The best place for this is on the power supply. Not the arduino

If the motor power supply is seperate to the arduino power then tie the two grounds together

What you don't want is all that ground current going through the arduino pins. These should only carry the signal return current that would be measured in the milli amp range only

Hope this answers your question

braedan · Answer

Thanks peteroaks. I get what your trying to say, but I am not trying to run the ground directly to Arduino -- just the ground provided by the motor controllers. sorry for any confusion; heres an sketch to better explain my predicament.

would the L298N module still work correctly? my thinking is since the is a ground connection to Arduino and the foreign power source from the other motor drivers there's no need for another one right? one or all three? thanks.

Robert Peter Oakes · Answer

So I would suggest one ground to each sabertooth as you clearly show, and one ground to the L298N driver, these are all signal grounds rather than "Power Grounds". If you rely on the ground via the saber tooth conrols then you may get too much nooise and even risk damage to the arduino.

As you have separate power to the arduino and the motor drivers, this is an ok approach and recommended.

Regards

Peter

Quick question: D.C. Power and motor controllers

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