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Arduino

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  • What sort of H-bridge? If it's the dreaded L239D or L298 you probably want more than 6v for the motor supply anyway, 6xAA would likely run your motors and your Arduino. Anyway, yes, you need a common ground between the battery packs, though preferably the Arduino and the power side of the motor driver have independent wires to the battery packs, and only meet there. Commented Apr 4, 2018 at 4:49
  • @ChrisStratton It's actually a motor controller my bad, it's this one: Sparkfun TB6612FNG. I just wasn't sure if I could power the DC motors with an external battery and connect ground to common arduino ground. So you're saying it's okay to use a 9V battery to supply voltage to arduino via its Vin and gnd pins AND use the external battery to power the motors and share ground with the Arduino? Commented Apr 4, 2018 at 4:55
  • @DenKart that driver requires some additional protection, pay attention to flyback when reversing polarity (changing direction of motor) and stopping the motor. The collapsing EM field can kill your arduino as well. Google for ways to protect your hardware. Do you have an oscilloscope? Commented Apr 4, 2018 at 5:19
  • The TB6612FNG is much better than the L293. That might be okay with 6v (4 cells) though you could also consider five or six - you can just run the motor at a lower PWM. Commented Apr 4, 2018 at 5:31
  • @ChrisStratton Also here's a sketch of my circuit, could you tell me if this is fine? ibb.co/iEhKMc I included the specs of the h-bridge too as a note Commented Apr 4, 2018 at 5:32