Launching balloons to high altitudes become more and more popular. Probably there are several reasons to do so, including low budget, so almost any enthusiast can afford, simple equipment most of them made from DIY parts. Probably this list could go on and on, but main idea that it is real fun to reach nearer cosmos.
In this project a balloon payload has a GPS tracker along narrow-band RF (434.650MHz) tracker that allows many enthusiasts to tune up to its frequency and help tracking the balloon. The heart of payload is Arduino board which takes care of Lithium cells and interfaces GPS and RF trackers.