Question regarding Arduino VIN ampere handling

I read in the data sheet that if a external DC power source is used (i.e. through the 2.1mm jack), then the VIN pin/port becomes a direct output that other devices can draw from.

If this is incorrect, please advise.

Now, assuming the above is true, then does that mean the VIN pin has a direct connection to the DC power source, and that if I run 2amps through it, it won't damage the Arduino board (since I understand Arduino is built to draw up to 1amp)?

Thanks for any assistance :)

VIN pin has a direct connection to the DC power source

True, VIN on the stackable headers is directly connected (well through a diode) to the + of the power pack/DC jack so you can use it for other devices as long as they are happy with the voltage you are using ie. 7-12v or whatever.

2amps through it, it won't damage the Arduino board

That would depend on the PCB track widths/lengths between the jack and the header and the ratings of both. I don't have a real Arduino here to look.


Rob

1) We do not know which "Arduino" board you are asking about. Please identify it.

Apologies, it is the Duemilanove.

3) I don't think any Arduino boards actually draw 1A on their own.

Oh, I was simply stating that parts going through the pins can in theory total 1A, and Arduino is rated to support that. The board + controller itself will not use that much power on their own, of course.

4) It isn't a particularly good idea to run significant power through the Arduino board. Loads that draw significant current should be powered independently of the Arduino board.

Of course, but I am short on both time + parts, and this would be the easiest way, given our implementation time-frame.

Oh, I was simply stating that parts going through the pins can in theory total 1A, and Arduino is rated to support that. The board + controller itself will not use that much power on their own, of course.

No the arduino isn't "rated" for 1A. There is a 1A series diode but trying to draw 1A through a part rated at 1A is a recipe for disaster.

Okay Mike, I think I understand, basically the short answer to my question is: No, it's not safe to draw 1A+ through the VIN port.

I guess a follow up question, since I need to change the design a bit: Do I need to feed it regulated power to the VIN pin to power the Arduino externally, or does Arduino have a regulator built-in that it can use if powered through the VIN pin?

Thanks.

Oh yes, that's the page which I found the VIN information last night--it simply escaped me, I was looking through the datasheet and didn't find anything. I almost thought I was crazy and imagined reading about the VIN info last night!

So just for clarification, the +5V pin expects 5V exactly, without any room for variance? That's a minor problem because we have a multivoltage external power supply that supplies 4.5 or 6, just not exactly 5V.

Is it possible to serialize regulators? i.e. Feed 9v regulated power into the VIN?

The regulated power adapter we have is this one: http://www.escience.ca/hobby/RENDER/0001/68/3040/13430.html

Our project involves powering an Arduino board, 4 servo's (accepts 3V to 7.2V) that uses approximately 160mA each to turn our load, and 16 LED's that are rated 2V@10ma at 18Mcd (which will be controlled by Arduino to turn on/off).

The power adapter, as mentioned before, produces 1700mA of regulated DC current at 3, 4.5, 6, 7.5, 9 and 12V.

Also, it would be great if someone can shed some light regarding my previous question:

Is it possible to serialize regulators? i.e. Feed 9v regulated power into the VIN?

Since the VIN expects an unregulated current, would any problem arise from feeding it regulated current?