power: not USB not battery

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?

Any suggestions?

Thanks,

hi

yes just plug your 5V source into the 5V and ground pins on the Arduino.

edit: put the power jumper to external!

D