Powering Arduino with a Battery

Make your Arduino projects portable by using a battery for power.  From the Uno and Mega documentation pages:

"The board can operate on an external supply of 6 to 20 volts. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may be unstable. If using more than 12V, the voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts."

I've found that using 9V works well.  You can simply connect the + end of your battery to Arduino Vin and the - end to Arduino ground (fig 1).  You should see the green light on the Arduino turn on to indicate that it is powered.

It's also a good idea to attach a toggle switch in series with this battery so that you can turn your Arduino off and on.  As shown in the images above, solder a toggle switch to the red lead from the 9V battery connector.  Connect the black lead from the battery connector to one of the Arduino's ground pins, and connect the lead from the toggle switch to Arduino's Vin pin.  Snap a battery to the connector.  Now your Arduino will turn on when the switch is closed and turn off when it is open (figs 5 and 6).

Comments

[agupta52]

Tried the same not working

[Gelfling6]

I've done similar, with a converted ATX supply, back-feeding +12V through the VCC pin. But, one word of warning, this still feeds back to the coaxial connector, then through the +5V regulator, and it's a thin trace on the bottom of the board. (all models from the Diecimila, to the present day Due and even the MEGAs,) I had to re-bridge this thin trace, when, powering a Duemilinove off the stock 9V battery pack, and a wire coming from the VCC pin, popped out of the breadboard, and touched a GND connection.. (Ironic, it was feeding a LM7805 regulator that was on the breadboard to power a couple of servos. guess what it touched? [o] )

[myth21]

hi i have one question...i have a buzzer that operates from 6-12v..and i put it on the arduino board that only produces 5v..and its working.. is it alright?wouldnt it damage my board??thanks

[amandaghassaei]

use a multimeter to measure how much current the buzzer is drawing, if it is pulling close to 40 then maybe try using a transistor to source the current directly from your power supply. does that make sense?

[JoshuaZimmerman]

A 9V to 2.1mm connector is less than $2.

http://www.browndoggadgets.com/store/accessories/9v-to-2-1mm-dc-jack/

Makes things far easier and way less complicated.

[bears0]

you can also take apart a used 9 volt and take the top piece with the connectors, solder wires to the back, solder those wires to a 2.1mm plug from an old power supply, and then cover the end with shrink tubing or epoxy. you just made one for free. I've already made a couple.

[amandaghassaei]

cool, you should make a photo instructable and enter it in tips and tricks!

[amandaghassaei]

it's not easier, now you need a plug and a snap battery connector and a switch. I like using the vin pin bc the barrel plug takes up a lot of space, if you want the arduino's usb port accessible to the outside you can't use the barrel plug, it's just too bulky.

[JoshuaZimmerman]

Ahhh, see, now you're putting it into context. Like your box. That makes sense in your situation.

The way your write up is worded it just seems as if you've got your Arduino powered up by this method at all times for some odd reason. Which makes no sense and seems overly complicated.

Now that you've placed it in context with a larger project when you wish to keep the USB port flush with your case, everything falls into place.

Maybe you could go back into your write up and add a paragraph explaining WHY you've chosen to do this method and put in a picture of your box.

[caitlinsdad]

There is the power supply jack at the end which takes a 2.1 mm barrel plug which makes a nicer connection.

[sofiadragon1979]

I agree w/ you there, I prefer to keep all of my headers open for use.

[Krayzi99]

In that case, i don't think you quite understand the sole purpose of the VIN pin. It's only reason for existence is to provide power from an external source with no connector plug. I personally like this better, as there are barely any wires in the way.

[waterlubber]

It is also good if you DO use the barrel plug as a safe way to hook up high-amp devices and not fry the board reg.