I’ve been toying with the idea of doing a balloon launch, perhaps carrying a full GPS and radio transmitter payload, but I think it would behoove me to get some experience attempting to find payloads that cost only a few bucks before risking hundreds of dollars. This would appear to be the answer: the Cricketsat.
These are little transmitters that are kind of like your key fob or whatever. They output a weak signal, but are capable of relaying some basic telemetry back via simple modulation. They cost about $10, and can be carried by a small balloon. Very neat.
You should check out a friend of mine’s product… http://bigredbee.com/
I’m going down the same path as you. Launch a few Cricketsats and then a Balloonsat. Go to http://www.anasphere.com/
and look at:
http://www.anasphere.com/AnaSonde_all.pdf
These are commercial Cricketsat devices/kits.
Check out my web, there is information there on CricketSats.
Also, check out:
http://cricketsat.com/
For CricketSat kits.
Bob