Hi, I've got a general question about how to power an arduino board. I have the NG (rev B I think).
Here's the thing: my doohickey already has a rechargeable battery in it. However, it's only 6V, and the arduino voltage regulator needs at least 7.2V. But the doohickey has it's own regulator producing TTL already. I can tap a lead off of it and get nice smooth 5V current. How do I power the arduino with that? I can't wire it to the external power input, because that goes to the voltage regulator. And if I put power to the USB, won't the arduino expect the USB port to be active? (besides, I don't have a spare USB connector at the moment.) Can I wire it directly to the 5V header, or would that fail the smoke test?