Do you always wanted a GPS/GSM device to locate your car in case is stolen? Now you can build your own. In the link bellow you will find all details needed including eagle files. In the image you see the main components of the device: GPS, GSM and battery module. Also it has a charger module build around MAX1811 CI. The device is not dependent on car battery, is just charging its own battery when the car starts.
Everything is build around EFM32GG-STK3700 board.