After doing some drawings and research, we built this 2-axis (roll and tilt) camera gimbal for a GoPro Hero3. This gimbal uses 2 micro servos to rotate the camera, controlled by the same Arduino board used for flight control. The advantage of doing this is that you already know the quadcopter attitude and only need to invert the angle to compensate pitch and roll.
The internal gears of one of the servos ended up broken after a hard landing. We are trying to find a metal geared servo to replace it and see how it goes.
Gimbal stabilization test (in front of the bathroom mirror.... sorry about that):
Even dough it's not very smooth, it does the trick.
Next version hopefully will use
brushless gimbal motors like this one.
