As a kid I saw a documentary on aerial kit photography and was instantly interested. So I built a rig that held a 35mm camera and pushed the shutter 30 seconds after launching the kite. Inspired by this article, I created a simple mechanical timer using a rubber band, an axel and a sewing needle as well as any materials I could find to finish the project.
I attached the rig to a kite and attempted to fly it at no avail. This is where I learned about weight constraints. It was a beautiful mechanical contraption which brought with it weeks of research and prototyping.