This is all you need:
1. A baseball cap
2. A screw that fits your camera mount (most likely a 1/4-20)
3. A plastic bottle cap
4. Two binder clips
5. A piece of rubber band (for example from an old bicycle tube)
First drill a hole in the bottle cap:
Insert the screw into the cap from the inside:
Cut a small hole in the middle of the rubber band and put the cap with the screw in it:
Attach the rubber band to the baseball cap on both sides with the two binder clips:
ALL DONE! Just mount your camera on the screw and you are ready to record videos hands free: