I built a simple picavet cross to hold and stabilize my camera when I sent it aloft using helium balloons.
A picavet is a self-leveling rig that attaches to a kite or balloon string. The picavet stays level even while the string changes angles when blown by the wind.
Step 1: Making Use of "trash" As Building Material
I wanted to put my Canon SD1100 IS up in the air. I wanted to shoot video not stills and this camera does great video.
The picavet rig will hold the camera level and facing down no matter what angle the balloon string is. The picavet is like a self-leveling marionette platform.
My camera fit into the foam packaging from my G1 phone perfectly.
Step 2: Parts and Stringing It All Together
I used the instructions on this page to figure out how to build and string my picavet http://www.kaper.us/basics/BASICS_picavet.html
I taped the packaging up at the corners and used scrap wood and eyes in the corners of the cross.
I didn't trust myself and restrung the kite string a couple of times until I convinced myself it was right. The key is that until there's weight in the picavet, the self-leveling doesn't really work. Empty picavets aren't as good as full ones.
Step 3: Now Go Launch Your Ballloon!
I used very small carabiner-like clips to attach the picavet to the kite string.
Watch this video of our camera launch to see how it all worked together: www.youtube.com/watch?v=O7RyHSwMvqs
I store my picavet attached to a coat hanger so the string doesn't get tangled up and it's ready to use the next time. (and there will be a next time!)
More details: www.JetCityOrange.com/balloon-photography/