Download the codes here Arduino simple shield potentiometer code: Arduino shield rc car: Arduino nano module L298P code: ...

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.

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.

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

Universal remotes are great but often rather pricey. If you want to make your own, Make shows you how to use an Arduino Yun to make a smart remote control you can control from any web browser.