Here's a project for Arduino fans with an old iPhone sitting in their junk drawer. Following these instructions from Will O'Brien, you can craft a remote start system that's triggered by SMS. The setup requires an Avatal 3117 remote start, an iPhone breakout board, an Arduino, a switching supply cell charger and a handful of transistors, resistors and diodes.
The system is controlled by the iPhone which talks to the Arduino controller. The iPhone can receive an SMS message that tells the car to start. 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
