External power to Arduino Uno R3?

Other Hardware General Electronics
1

Hi,

I am trying to supply external power to an Arduino R3 board.

Currently I have power supply to a servo motor using a 4-battery pack (1.5V x 4 = 6V).
I am currently powering the arduino through the USB on the laptop.

Questions:

  1. From what I understand I can add another 4-battery pack and connect it to the "Vin" pin on the board in order to power it without the USB connection (NOT the "5V" pin as this will bypass the regulator right?).

  2. Can I actually use the 6V I already have to power both the motor and the arduino? Or is there simply not enough power from just 1 pack and I should add the other one..?

Can anyone verify these issues?

Thanks! :slight_smile:

2

6v is not enough to get 5v on the board with a standard Uno board, they cheaped out on the regulator, and it can't give you 5v with 6v input due to dropout - so if you power it with Vin, you won't get the full 5v... An external low dropout regulator could be used to supply the 5v pin and use a 6v battery pack with the Uno.

It is recommended to separate the supplies for the Arduino and the motors, because motors tend to put lots of noise on the power source, which can cause the Arduino to reset.

3

Hi DrAzzy,

Thanks for the reply, I didn't know that.

Do you have a link or suggestion for a specific regulator?

Thanks.

4

Just use a 9volt battery on the DC jack of the Arduino, or run the Arduino from a mains powered 9volt supply.

Run the servo motors from the battery pack that you already have.
Leo..