Arduino nano v3 ATmega328P-AU RAW voltage and USB

Would it be fine if i had both the USB connected and a raw 19.5v connected to pin 30? I think i read somewhere that it will automatically take the higher current as the main source but i wanted to just double check if that was correct before i go and hook that up for final :slight_smile:

Reason behind me asking is if the computer i have the arduino hooked too (via USB) goes off then the arduino will no longer have power to do commands (like turn the computer back on) so you can see my problem there with not having any power through the USB port if the motherboard goes off. I use a relay attached to the arduino to mimic the soft button press to turn on/off the computer.

Thanks.

Yes, although I am not sure what pin 30 is. You need to use the power jack.

I am using one thats layed out like this:

http://arduino.cc/en/uploads/Main/ArduinoNano30Schematic.pdf | http://www.ebay.com/itm/110896151860?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

I figured the "VIN" was the input for the current so i used that... seems like the 5v output on pin # was over 10v when i did that?

Where would the raw power be if that was not it?

David

StealthRT:
I think i read somewhere that it will automatically take the higher current as the main source

Higher voltage, not current.

StealthRT:
I figured the “VIN” was the input for the current so i used that… seems like the 5v output on pin # was over 10v when i did that?

pin #?

Doesn't seem like a pin number is applicable any more If his 10V measurement on the 5V source was correct, likely he made himself a small paper weight (Not big enough to qualify as a brick)... IMO

Doc