What wall adapter to buy for an Arduino that needs more power?

Hi there!
How may I buy the wall adapter? Is any special voltage/size?
I need more power to my arduino, but I don´t want to burn it, or to but some adaptor that doesn´t fit in it.
What should I ask for?
Thanks for your help!!!

Well seeing as you don't specify how much extra power you need, how about this:


The size of it does not matter one bit. You need one that is the right voltage & amperage. What Arduino are you using? The wrong voltage could fry it. The amount of amperage listed on the power supply is not how much power will go into your Arduino but rather how much power CAN go into the Arduino. You can not buy one with to much amperage as the Arduino will only pull as much as it needs. Less then one amp should be fine for most projects. If you are using a 5v Arduino (Uno, MEGA, ETC) this one will work…

Best of luck!

The size of it does not matter one bit.

I think they meant "barrel size" from the context.

You need a 2.1mm barrel plug w/ positive tip.

Thanks for your replies!!!
I´m building as my first arduino project a toy car with 2 DC motors that uses bluetooth, and I´m using the Adafruit motor controller, that sucks a lot of power.
I´ve tried adding a 9v battery but after not getting the wheels moving at all, I´ve read that that´s not enough, so I thought that it would be best to get the power from the wall instead.

Using something like you kindly suggested (240V AC to 9V DC unregulated PSU (600mA), or Wall Adapter Power Supply - 9VDC 650mA), wouldn´t I be in the same 9v-is-not-enough issue? Or that´s not the case because it would get the power from the wall?

Thanks -again!- for your kind replies!

Your Arduino probably doesn't need "more power", but your project's motors do.
They're separate issues.
The Arduino should be connected to a power source of its own, something better than a "9V battery", like a 6xAA battery pack.
The motor side of your motor controller needs a power source of its own.
You don't have to worry about excessive input voltage to or overburdening the Arduino output situation that way.

"2 DC motors" is vague, but still, keep the motor voltage separate. The Adafruit motor shield documentation has more information.

The voltage isn't (necessarily) the problem when trying to run DC motors from Arduino. (It can be depending on specs of the motors....) Without being too specific & detailed, the Arduino board converts it's power source to 5v anyway.

More often, when having "not enough power" issues, it's current (mA's). A little 9v battery does not have enough current to drive much. Wall wart, DC adapters, and larger (automobile-type) batteries supply much more current.

I advise checking DATASHEETS for your motors (and anything else attached) to calculate how much current, and voltage, they need. Post that info, and we can give you a much better answer as to what you may need to use.

Thanks —

Hi again,
The DC motors are generic: 4.5V-6V -- 250 mA
Thanks for your help!