The Gimbal

The recipe:

1 x 3D-printer (A reprappro mendel in our case)

2 x standard 9g servos or similar (we used servos with metal gears)

1 x Raspberry pi camera module

Part of the task of making a system for acquiring photos and video from a flying vehicle is the need to compensate for the vehicle's motion. A great way of compensating for this is to make a device that if our vehicle rolls right, this rolls the camera to the left to compensate and keep the camera steady and horizontal in reference to the ground. For different applications you want to compensate for different maneuvers, roll, tilt and yaw. What we want on our hexacopter is only to compensate for roll and tilt. This keeps our camera level with the horizon (parallel to the ground) and this is just what we need. The rest we can compensate for in software post-processing. The idea is simple, 1 servo per axis of rotation, using the inverted gyro signals from the APM (the chip that controlls the hexacopter) and feeding these to the appropriate servo.

We got a raspberry camera module which is lightweight and really small, we want to shockproof our gimbal a bit so we went for some beefier servos with metal gears. You could probably do this with a standard 9g blue servo, they are almost the same dimensions, depending on manufacturer.

The whole system consists of 2-4 parts. One arm from the first servo to the second, making them perpendicular in the z-axis, something to attach the first servo to our frame and something to attach the camera to the second servo. With the little CAD-experience i have I came up with the following design.

This is the main part, all you need more then this is a box for your camera and something that attaches your gimbal to the frame. It turned out really small and simple, takes about 1.5h total to print without the bit that attaches to the frame and the camera mount. The camera mount will be made when we get the camera so we see that it fits. The almost finished product looks like this, where you attach your camera to the bottom servo (pointing down towards the ground in our case) and the top servo attaches to the frame.