1 battery 2 devices at different voltages

I would like to power my Arduino board up and also power a small dc motor (7 or so volts). Would it be possible to use one battery to power both with out ruining my Arduino? I would love some documentation to point me in the right direction.

See the product page for your Arduino board.

The Uno, for example, recommends input voltage of 7-12v http://arduino.cc/en/Main/arduinoBoardUno

So a battery at an appropriate voltage for the motor would also be fine to power the Arduino.

Yes but don’t power the motor from the Arduino! use something like 6 x AA = 8.2-9v input that to the Arduino via Vin or socket, also take it to the motor, connect GNDs.

You do not say if you want to control your motor or how?? if so you will need extras…

We need more info, Regards.


In general you'll only get grief trying to power the motor and Arduino from the same source unless you are sure:

1) That the battery can give enough current for the motor at stall at all states of charge so the voltage does not dip. Measure stall current and battery internal resistance to find out?

2) The you have some filtering between motor supply and Arduino Vin to suppress inductive voltage transients - definitely lots of decoupling for a start.

3) That you wire the motor power leads separate from the Arduiino power leads, ie they meet at the battery.

For 2) a DC-DC converter can be a possible choice.

Basically separate supplies is much much simpler.