Using two power supplies with arduino and one servo

Hi, I have a very newbie question but I was unable to find a solution using the search engine.
I have two 4AA battery packs (1,5x4= 6V).
I want to use the first for Arduino and the second for a servo engine.
The Arduino sends input to the servo engine via a PWM pin.

I need to link the GND of the two power supplies to make it works?
Or I will short circuit my arduino uno?
What must I carefully avoid :slight_smile: ?

I'm also new to Arduino, but have used dual power supply to operate a 34 size stepper motor. I used my pc's usb to power the processor and a 12 volt, 20ah SLA battery to move the stepper. I did make both grounds common with no problems in order for my motor driver to work. My motor is wired as a unipolar and the battery positive lead went to a power resistor and then to the motors two common leads.


like redtank said. I do it the same way

when i use dual power supplies i usually power my arduino from usb. I might use an additional supplie to power i.e. some LEDs. What I do is connect the plus of my battery to whatever requires the power (in your case the motor) and the minus to an arduino ground pin.

I am not a pro either, but I have done this and similar setups for verious projects and as of now have not broken an arduino (or started a fire or anything else nasty) while doing this.

The term "Ground" is something we all made up to refer to the reference plane. Remember that voltage is relative to some reference. In this case that reference is 0V.

So all supplies and components need to share a common Ground to work (except in the case of isolators, of course.)