Can I use a 9v battery with a five volt voltage regulator to power this board or and other battery power? Like 2AA? Thank you
Yes. It may only last 15 minutes on a 9V deprndin on what you are doing, but you can do that. 2AA only gives you 3V, so no way to get that to 5V short a boost regulator.
Gerald
You mean something like this:
As Gerald said, you need to be careful what you are running off the board. Full blast the board alone is about 1W from tests others have done.