This is a mount I designed to shoot video with my Samsung Gear 360 camera from a realistic passenger view. It fits into the headrest on my FRS (14mm post) and should fit any others that have the same size headrest. Just remove the headrest, slip the post in the hole, and go.

There is nothing on the print to keep it straight once it's inserted into the hole. so it can be spun freely by hand, but has yet to slip during actual driving for me. I think it's because the 360 camera is straight in line with no weight hanging out to cause an imbalance and inertia to swing. Other cameras on this mount MAY cause it to turn.

Required Materials:

• 3/4" (19mm) long section of 1/4"-20 threaded rod. Lowes sells a 2ft section for about $6, and a hacksaw will quickly take it down to size. Alternatively, you could just cut the head off a bolt and use the thread. Threads are printed directly into the piece.
• Mini ball-head camera mount. I use this one and the 3D printed piece is designed to match the diameter of it. Anything with a standard 1/4"-20 camera mount on the bottom should work though.

Time lapse test video showing off the view is here.