Did he just screw the compass to a metal plate and put it inline with an actuator, I'm no expert but surely any kind of metal or electronics would mess with the compass surely ?
Also why did the video at 7:50 jump as if something didn't work correctly ?
I'd rather the legs not retract. Without legs there is nothing protecting the hanging camera from slamming into the ground or an object if something goes wrong. Legs aren't great protection, but at least they are something.