External regulated power

Couldn't find the exact answer I need via search so anyway I have an arduino uno (r3) and I want to power it with an external power supply, 5v and it's regulated. I don't need to go through the onboard regulator, so is there anyway to supply the regulated 5v to the uno without going through the usb connector or the regulators?

If I have to go through the usb port, the regulator also has a usb port where you can supply power through there. It does not have a pass-through so I wouldn't be able to monitor the serial port so (and yes I know this is a round about way) would I be able to splice a second usb cable into the first and tap into the data lines through the second cable, and supply power with the first? Would this interfere with the data transfers? Could I ground the shielding wire to the power supply to keep the shielding?

Thanks!

so is there anyway to supply the regulated 5v to the uno without going through the usb connector or the regulators?

Yes connect to the 5V pin on the Arduino. (and ground of course )

I thought so, but the official arduino specs are a bit fuzzy on that. How about the spliced usb cord? I want that option in case I don't go with a separate 5v rail, and that will tie up the 5v pin...

You can't tie up your 5V pin. You can connect it to as many other things as you want.

Perhaps if I explain another way. I wanted to keep away from a bunch of jumpers. I suppose I could put the 5v on a breadboard, jumper off that to the 5v pin on the arduino, then just go off the 5v on the breadboard for the sensor connections, etc. etc. I know the limits of the board, 200 ma total, etc. etc. I just want the option of going off a spliced usb cable if I need it.

Yes you can splice a USB cable but you will still have a 500mA current limit because there is a poly fuse on the Arduino that stops you drawing more current.

Yea, I know. All this is just for prototyping anyway. I'll be using a wireless link after that so it won't be an issue. At any rate thank you for all the info. The official Arduino board specs are a bit fuzzy on how to use a external source without going through the onboard regulators. I suppose I could have avoided all the questions if I just downloaded the schematics anyway :slight_smile: