You have too much going on for untested software and hardware. Yank half those wires - the one going to the ping sensor, specifically. If you can't get the iPad to do anything, it doesn't matter what is in front of the ping sensor, does it?
Write a simple script that does some stuff in setup(), with NOTHING in loop(). Does the iPan react? If not, it isn't wired correctly or you are sending the wrong stuff to it.