You need: 

Camera: SJ4000 Sport video camera
44.5mm diameter biconvex optical lens
Safety goggles where you can remove the glass from. Use the picture of the glass in the gallery to find goggles that fit (print it out and go to the hardware store and compare with what they sell).

Print the parts. Use a crosshead screwdriver to sovereign (open up) the wholes in the centerunit a little so that the pins slide in easier.

And assemble.

Updates on this model will be posted to Thingiverse.