Arduino Uno used to create a human following car/robot, all with parts that you can find online for only a few bucks each ...

[Dave] wanted to make an Arduino robot out of a remote-control 1950 Mercury. He removed the RC portion from the car and kept the drive and steering motors. The idea was to use three ultrasonic ...

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.

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.