[Buxtronix] wanted to know where his cat (named Ash, but we thought Socks sounded much more cliché) was going when on the loose. He designed a GPS tracking collar and a way to map the data it collects.
The hardware actually turns out to be very simple. He needed a GPS module to gather location data, and a way to store that information having decided that live broadcast was not feasible. He hit SparkFun because they have a GPS module that is small enough for a cat collar, and outputs data with one serial pin. Unfortunately this module is no longer available, but if you have a similarly sized replacement let us know in the comments. Data capture is made easy by this device, you just need to record the serial data as it comes down the pipeline. [Buxtronix] used an OpenLog board as it dumps the data onto an SD card. When [Ash] returns from his roaming, [Buxtronix] grabs the SD card, and uses a Python script to convert the NMEA data to KML format which can be overlaid on Google Earth and Google Maps.