A while ago I saw this video: https://www.youtube.com/watch?v=aqncOP7OzMg&t=51s
A while ago I also saw this competition.
In my head I put together these two ideas, and with some simple design software (tinkercad, the most basic of all), I put this together.
1. Print out one of everything. (the handle is optional). Put the parts together, with the fin bumps facing out and the base bumps facing up.
2. Drill out the holes. See pictures. Use a drill, or grab pliers and a nail. Heat up the nail in a fire (stovetop is fine) and melt the holes into the plastic.
3. Get some fishing line (I used red string for visibility but you don't want it in your videos too much.
4. Cut three pieces 6-8 ft each. Tie them in the holes.
5. Get the other ends and tie them together, making sure that the base is level to it.(basically make them the same length)
6. (optional) add the handle. If you decide to use the handle be sure you tie the string on secure, yet have it still be able to rotate freely.
7. Test it. Don't put the cam in just yet. Hold it 1 foot from the base, and as you swing slowly let the string out. when you get to the end you can pick up the speed. To stop it, slow down, grab further up the string, and stop, arm high, so it doesn't hit the ground.
8. Adjust. If it wobbles, faces sideways, or one string is loose, adjust it, until you get all strings tight and facing you.
9. Settings: I reccomend 720p 120fps, but if you need HD, use 180 60fps and slow it down in post.
10. Put cam inside, and secure with a rubber band or two.You're done! enjoy!
layer heigtht: .15-.2mm
material: PLA or ABS (I prefer PLA)