If some of you want to try something new, you might be interested in temporarily attaching a regular point and shoot camera to your helmet. I did this to get a POV video while crawling through a cave we've been digging in the US. The setup was very easy. All I needed was a segment of 1/4"-20 threaded rod and a nut. I put the rod through a preexisting hole in my Edelrid helmet and adjusted the angle with a modified plastic bottle cap. The result was okay, but if I could do things over I would have used a camera that was better in low light situations or I would have used a stronger headlamp.
Crawling to dig
Crawling to dig