I was watching a video of a homebuilt ROV on YouTube and it had ball type compass placed in front of the camera viewport. http://www.youtube.com/watch?v=1VvX0pxmmNQ&feature=player_detailpage#t=32s
I was wondering:
a) what's the official name of that part? Ball compass?
b) Where do you get them from?
I've seen those types of compasses in cars and on boats before, do you think you could just use one of those or would they break under pressure?