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Topic: Serial communication fails with motor driver using external PSU (Read 997 times) previous topic - next topic

LarryD

On the other hand, supply the +5 volts to the driver using an external 5 volt supply, not the Arduino's +5 volts.
The way you have it in your schematic isn't the same as how you have it wired up!

yedlosh

Thanks a lot! :) I managed to find some additional 5V PSU for powering driver logic and it fixed the problem. But I still fail to see why is problematic to use the Arduino's 5V output in first place..

LarryD

There are current limitations to the Arduino hardware.
The way you have it in your schematic isn't the same as how you have it wired up!

yedlosh

I'm well aware of that. But the current draw of driver logic should not exceed some tens of mA, while Arduino on USB should be able to source up to 500mA on +5V pin ;)

yedlosh

Just measured it, current draw is 30mA.. should be no problem even for an IO pin ;) I think the problem lies somewhere in the connected grounds of external PSU and USB.

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