External power to yun

Hi, i need to externally power my yun, can i simply provide 5V and ground into the 5V and ground headers?
Thanks!

Funny, I just sent a 'power shield' board design off to OSH Park to have fabbed to allow me to power the Yun (or any Arduino board with the standard shield form factor) from any voltage source AC/DC from 7V to 30 :slight_smile:

mactsk:
Hi, i need to externally power my yun, can i simply provide 5V and ground into the 5V and ground headers?
Thanks!

Nope. Won't work. Personal experience.

For a Yun, you have to feed external 5v to the Vin pin on the Yun. The fun part is that you don't want to do this on an Uno or most other Arduino boards. If you feed more than 5V to Vin on a Yun, it will fry your Yun. There's a not so happy post about feeding 9v battery directly into Vin on a Yun.

Also, you can just read the info on arduino.cc of which the most relevant portions are replicated below:

From http://arduino.cc/en/Main/arduinoBoardUno:
VIN. The input voltage to the Arduino board when it's using an external power source (as opposed to 5 volts from the USB connection or other regulated power source). You can supply voltage through this pin, or, if supplying voltage via the power jack, access it through this pin.
5V.This pin outputs a regulated 5V from the regulator on the board. The board can be supplied with power either from the DC power jack (7 - 12V), the USB connector (5V), or the VIN pin of the board (7-12V). Supplying voltage via the 5V or 3.3V pins bypasses the regulator, and can damage your board. We don't advise it.

From http://arduino.cc/en/Main/ArduinoBoardYun:
VIN. The input voltage to the Arduino board. Unlike other Arduino boards, if you are going to provide power to the board through this pin, you must provide a regulated 5V.
5V. The power supply used to power the microcontrollers and other components on the board. This can come either from VIN or be supplied by USB.

edit: added link to Yun info page.

Which is why my shield design allows you to select either the 5V or VIN pins via a jumper - that should make it compatible with Yun and other boards...

Ok so i can make a shield with a 7805 connected to vin and ground, in this case i get the 3.3V on the 3.3V pin? (don't need it actually, just to know)

mactsk:
Ok so i can make a shield with a 7805 connected to vin and ground, in this case i get the 3.3V on the 3.3V pin? (don't need it actually, just to know)

Yep, that is what schematic shows. A bit of RTFM also reveals the maximum current draw is 50 mA on the 3.3V pin, so don't plan ever doing much with it!

My shield design uses a 2A bridge rectifier (primarily to avoid polarity reversal - it is for automotive/mobile/battery input by design), an 7805CT which can provide 2.2A at 5V, a Hall sensor input (which can be disabled by jumper), jumper selection of where the 5V goes (5V or VIN), jumper selection for the Hall interrupt (any interrupt on the Leonardo/Yun can be selected) and pass through headers for everything. I will be using the 15mm stackable header on this shield as the Yun doesn't play nice with the usual ones.

I also provide inputs on the shield for a power on/off switch and an external reset button.

There is easily enough real estate left to add a 3.3V regulator and provide that to boards stacked on top (and NOT to the Arduino below) if you need more current. For grins I'll add that ability to the board when I'm done with the Christmas visits :slight_smile:

When the initial boards are tested I'd be more than happy to send a bare PCB and parts list - it is all through-hole so soldering it is easy :slight_smile:

spdonegan:
When the initial boards are tested I'd be more than happy to send a bare PCB and parts list - it is all through-hole so soldering it is easy :slight_smile:

Would this work to allow power input from a (series of) solar panel(s)?

Ralf