Arduino YUN - VIN pin

Hello to all,

I have an Arduino YUN that I am powering through the micro USB and a samsung smartphone charger rated at 2A.

Can I access directly this power source from the VIN pin of the YUN? If so what is the maximum power (or Amps since I am feeding 5V) is safe to draw from that pin?

Thank you for your attention,

Pintovski

Hello Pintovski,

The Vin pin is designed for providing power to the Yun and not the opposite. There is a diode that let the current flow in only one direction.

So if you power the Yun from the micro USB connector you can't access to that power source.

pintovski:
Hello to all,

I have an Arduino YUN that I am powering through the micro USB and a samsung smartphone charger rated at 2A.

Can I access directly this power source from the VIN pin of the YUN? If so what is the maximum power (or Amps since I am feeding 5V) is safe to draw from that pin?

Thank you for your attention,

Pintovski

You can’t draw from VIN, but you can from 5V pin.

I assumed the YUN worked in a similar fashion as the normal Arduino. In the official website [Power Pin heading] it says:

"[VIN] You can supply voltage through this pin, or, if supplying voltage via the power jack, access it through this pin. " http://arduino.cc/en/Reference/Board?from=Guide.Board

If what you suggest is correct and I cant draw from VIN, then my question can be reformulated as:

Can I draw 2-5A from the 5V pin of the YUN?

Thank you all for your inputs.

J

On most of the boards, the barrel jacks input goes thru a diode that is Vin, which then feeds the 5V regulator. USB power has no path to get back to out to Vin.

The 5V regulator on most boards is only rated for 800mA. 2-5A would not be possible. I doubt the Yun is any different. Check the schematics.

mart256: You can't draw from VIN, but you can from 5V pin.

... which really only provides about 4.5 volts because of another diode in the circuit.

I'm not finding a specification of how much current you can safely draw from that pin. Personally, I'd be leery of drawing more than around 100 mA.

pintovski: I assumed the YUN worked in a similar fashion as the normal Arduino.

No, actually, it's quite different. Read up on these pages: - Yun - Hardware Guide - Yun - Getting Started Guide - Yun - Arduino Playground

Can I draw 2-5A from the 5V pin of the YUN?

No way. If you're powering the Yun from the USB port, you're automatically limited to 500 mA total by the USB specifications, and that's including the few hundred mA used by the Yun itself. That doesn't leave much for other circuits.

pintovski: I assumed the YUN worked in a similar fashion as the normal Arduino. In the official website [Power Pin heading] it says:

"[VIN] You can supply voltage through this pin, or, if supplying voltage via the power jack, access it through this pin. " http://arduino.cc/en/Reference/Board?from=Guide.Board

If what you suggest is correct and I cant draw from VIN, then my question can be reformulated as:

Can I draw 2-5A from the 5V pin of the YUN?

Thank you all for your inputs.

J

Well, there's no regulator, so theoretically you could if the power supply provides 2-5A. But you mentioned "the micro USB and a samsung smartphone charger rated at 2A" so your limit would be 2A.

But, I don't know if the cooper traces inside the Yun PCB can hold 2A without melting.

sonnyyu: Apple change the game, The new motherboard usb port has more than 500mA. Even old motherboard board you could get it by install software driver.

Gigabyte Asus

FYI.

0.5 amps - the max current a typical USB port puts out 1.0 amps - the minimum current an iPad needs to slow charge. 2.0 amps - the minimum current an iPad needs to do its normal charge (ie same speed as the included wall adapter)

mart256: But, I don't know if the cooper traces inside the Yun PCB can hold 2A, which I doubt.

... or the rest of the power related circuitry: to get from the USB input to the 5V output pin, the current must pass through two diodes which are only rated for 1 A. Being conservative, it's best to plan on using no more than 80% of that, or 800 mA. Take some power out for the Yun itself, and perhaps you could get away with drawing 500 mA out of the 5V pin.

If you need that much current, you are probably better off powering your extra circuitry directly from the power supply, rather than going through the Yun. Then, take 5V from that extra circuitry and feed it into the Yun using the VIN pin. In other words, have your add-on circuits provide power TO the Yun, not draw power FROM the Yun.

ShapeShifter: If you need that much current, you are probably better off powering your extra circuitry directly from the power supply, rather than going through the Yun. Then, take 5V from that extra circuitry and feed it into the Yun using the VIN pin. In other words, have your add-on circuits provide power TO the Yun, not draw power FROM the Yun.

Yes, that was what I was thinking. Just wondered if I could avoid the added cost of a micro-usb adapter in my shield...

Thank you all for your comments.

This was my first post, and I am already convinced this is a wonderful community. Keep up the good work!

P

@pintovski, it appears your questions have been answered.

For other that may read this far in the future, As ShapeShifter has pointed to (others have suggested) we can quote the follow:

From: Yun - Hardware Guide, in the power section:

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.

From: Yun - Getting Started Guide in the section Differences from the Arduino Leonardo

There is no built in 5V regulator. If you power your Yún with more than 5V, you will likely damage it. If you are not powering the Yún from the micro-USB connection, you can apply power to the VIN and 5V pins on the board. If using the VIN pin, you cannot provide more than 5V, it will damage your board. It is recommended to power the Yún from the USB connection whenever possible.

From: Yun - Arduino Playground in the section Power consumption of the board

Power consumption in mA
Configuration                              min typical max
WiFi on, no wired connection, no sd 170 240 300
WiFi on, wired connection, no sd     -  277  -
WiFi on, wired connection, no sd, max. load     315

pintovski: Yes, that was what I was thinking. Just wondered if I could avoid the added cost of a micro-usb adapter in my shield...

::::SNIP::::

@pintovski, We got a little excited answering this question... most are "I cannot connect My Yun"

You can also use the POE (Power over Ethernet) SEE: Yun - Hardware Guide, the section on Power

Jesse

Thanks.

POE is a great (but expensive) feature. I am using the Wifi so no power there…

P