Randy Sarafan, who also happens to be the Technology Editor over on Instructables, gutted a remote-controlled car and swapped the parts for an Arduino board.

The Arduino code tells us that the valves will be opened as long as the remote up/down channel is above/under given values.

To some of us, hacking an RC Car to simply follow a black line or avoid obstacles is too easy, and we’re sure [Shazin] would agree with that, since he created an RC Car that follows your face ...

A perl script running on the iPhone will then send the command to the Arduino. When it receives the start command, the Arduino will ground the wire to the remote start and fire up the car.