Cars get stolen all the time, but if you want to track yours and make sure you can always find it, Instructables user Jayvis Vineet Gonsalves shows off how to build a system to track a stolen car with an Arduino.
The system uses an Arduino Uno, a GSM shield, a GPS module and a few other smaller parts. The idea here is pretty simple: you hide the Arduino somewhere in the car, hook it up to the battery, and then it connects to GPS. When you want to find your car, send a text message, and you'll get the coordinates sent back to you.
It's an inexpensive system that's inconspicuous and easy to hide so thieves won't think to pull it out. Head over to Instructables for the full guide.
Athena: The Global Car Tracking System [Instructables]