So just wondering if any of the pins on the external bus pass through the 7805 on their way in/out. I plan on connecting a 12v battery to the power in, and then hopefully getting 5v out to power a cheapo MP3 speaker that usually run on 2 AAs. I'd guess 5v is probably in range, where 12v could fry the amp. I'll power the LCD screen from the bus too.