...really wasn't anticipating a complicated project.
Well, see it through.
I can't see your schematic here at work (that picture site is blocked.)
What's the power source?
Is it connected through the barrel jack (re. Q. DVDDoug)? Or is it connected to "+5" on the power header?
We can do some "impedance matching" (1 transistor, two resistors - easy), but I can't post that till later this afternoon.