I've been using the TinyDuino with an SD card reader, and GPS and have had no problems with it running off my computers USB or a 9v batt with a 7805 inline regulator attached to the +/gnd directly on the TinyDuino. 

However, I just added a protoboard with two MQ-style sensors which each need 5v to operate.  Everything runs fine when plugged into my USB, but the 9v batt seems only to power the GPS and SD logger.

Any ideas?  Possibly too low amperage from a standard 9v alkaline?

Here they are being powered by the USB...the sd logger and gps are off here, but when they are on they do fine on USB too.

Nevermind.  It looks like a variation of this question has been answered several times in the forum, and I was too impatient to search through.  I hooked up to VCC and now they are running fine.