[RESOLVED] Power Jack for power and USB for communication

Development Tools IDE 1.x
1

Hi guys, (sorry again for my english)

i have some Arduino Uno boards and i'm using a GSM Shield on it.
I read earlier that, with this GSM Shield, i can't use the energy provided by the computer through USB cause it may be not efficient, so i plan to buy something to give energy to the Arduino through the Power Jack.

I was wondering if there will be some problems by supplying arduino through power jack and still communicate with him through USB. Will the board be intelligent enough to select the right source of energy or should i change some settings to indicate which source is energy and which is communication.

Thanks to all for reading,
Best regards,

Laura

2

First, your English is better than that of many English First Language users Laura, so no need to apologise.

Second, afaik, Arduino chooses the higher of the two voltage supplies- I seem to remember reading that in a post recently. So it'll power the card from your (say) 9V wall plug adaptor, while still communicating on the USB with its native 5V. (I think.....)

3

Ok thanks for that accurate reply =)

and thanks for my english, i appreciate !

See you =)

4

Maybe unmark it as solved until you get a couple more replies just in case I have it back-to-front

5

The DC jack input goes to a 5volt level converter. so basically the arduino gets 5 volt from the barrel.

The arduino ALSO gets 5 volt from the USB, if these voltages were different,the there would be potential difference and power would run from pc to battery or battery to pc, but since the levels should be it shouldn't be a problem.

(You'd even have more power available because USB ports can supply less than batteries I believe?)

6

Have a look at this thread which says that the external (non-usb) supply wins, provided it's adequate.