I would like to power up the Uno via a battery and have uno ground reference be at respect to the battery. however, I would also like to read data through the USB wire. Is there a way to do this?
Thanks
What kind of battery?
If you want to isolate the PC ground from the Arduino ground I think you'll need some sort of USB Isolator. I don't think you can cut the USB ground wire and expect the USB signal wires to work.