Running Arduino off 5 volts

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mos6502
 
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Joined: Sun Nov 23, 2008 4:33 pm

Running Arduino off 5 volts

Post by mos6502 »

Hey guys,

Ive been messing with the arduino for a while now, but for some reason I only recently needed to run it off of 5 volts. Unfortunately, it looks like the Vin is connected to the voltage regulator, in which case 5v is too low to run it. Just wondering if anyone else has experience running an Arduino with 5v? And how you went about doing it?

adafruit
 
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Joined: Thu Apr 06, 2006 4:21 pm

Re: Running Arduino off 5 volts

Post by adafruit »

you can connect 5V directly into the pin marked 5V

mos6502
 
Posts: 25
Joined: Sun Nov 23, 2008 4:33 pm

Re: Running Arduino off 5 volts

Post by mos6502 »

Awesome. Thanks!!

jolyrojr
 
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Joined: Mon Dec 28, 2009 6:14 pm

Re: Running Arduino off 5 volts

Post by jolyrojr »

hey thats handy! I have been using that for 5v out, I didnt even think about using it for power in... I was looking at minty boost, wondering if I would need a small boost regulator circuit to power from 5v. I saw conflicting info about using 12v for power, one place I looked said yes, one said no. 12v in would be handy for integrating an atmega into some exhisting circuits I have. Any definitive word on that?

Entropy
 
Posts: 472
Joined: Tue Jan 08, 2008 12:43 am

Re: Running Arduino off 5 volts

Post by Entropy »

jolyrojr wrote:hey thats handy! I have been using that for 5v out, I didnt even think about using it for power in... I was looking at minty boost, wondering if I would need a small boost regulator circuit to power from 5v. I saw conflicting info about using 12v for power, one place I looked said yes, one said no. 12v in would be handy for integrating an atmega into some exhisting circuits I have. Any definitive word on that?
The 7805 will handle 12v, but you almost definately want to heatsink it if you give it 12v, and also be careful even then not to draw too much current.

For a given 5v current consumption, using 12v nearly doubles the power dissipation of the regulator. (x milliamps * 7 volts instead of x * 4).

I remember once seeing a design for a switching regulator that fit in the board footprint of a 7805, however i was significantly taller. Ah, I found it -
http://www.instructables.com/id/Switchm ... regulator/

There's a commercial variant from Dimension Engineering.

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