Alex had previous experience with his GPS logger, so recently he decided to build another project called GPS alerter which would send SMS when device is located in a certain area. Device also is equipped with accelerometer which allows detecting movement, so it could activate GPS module and start getting data. This helps to preserve battery life as there is no need to check coordinates while it is at same coordinates.
For this project he uses Atmega8 microcontroller which read GPS data through serial port. To send SMS messages there is an old Nokia 3210 cell phone used which is fairly easy to interface.