Electronic – arduino – Use battery negative as ground

arduinoground

Powering an arduino board using batteries via the the barrel connector, is it ok to use the negative terminal as ground wherever its needed?

For example, I have a shield that takes +5 and Ground from arduino pins – is it ok to use the negative from the battery as the Ground?

UPDATE: I attach a rough sketch. I've ignored control lines etc. The M is for a motor that is being controlled by the H-Bridge which requires +5/GND from arduino and external power.

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Best Answer

I'd wire the set-up like this: -

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Ground (pin 8 typically for an L298 but will be different on other devices) on the H bridge becomes the star point for the connections to the rest of the "system". This means that motor load currents are kept away from the arduino - these can cause problems. Also keep the wires to the motor battery and to the motor as short as you can to avoid induction into other circuits.