April 2, 2014 Update:
In-flight test of new holder GimbalBase8 (GimbalBase7 did have a design flaw which would not allow to mount the motor ;-)). Still jello effect. Then Felix found the solution: Video recorded with 25 frames have jello, 30 some and videos with 60 frames are just perfect (http://youtu.be/Qj32H0mnQfI). Thanks Felix for this insight! Now the design process is finished.
People report that they were not able get the rubber buffers from my previous post. It might be easier to get the M3 Flex-Loc buffers and use the Damper80 caps with M3/20mm screws in combination with the white stock buffers. I don't want to take credit for this damper design, as a similar one is used by other gimbal systems (check their product if 3d printing and soldering does not resonate with you ;-)).
March 30, 2014 Update:
New design GimbalBase7 with vertical PCB mount, 8 mm increased distance from cam to ground, 9.5 mm diameter for original dampers, no holder for additional tracker, moved cam 5 mm backwards. This design is based on feedback and not yet tested in air.
March 29, 2014 Update:
The key to the success of this gimbal is vibrational damping. The solution I use is to equip the stock dampers with a cap on each side (I added two parts, one for the top with 8 mm diam and one for the bottom with 7.5 mm diam), placing a 6 mm long rubber damper with M3 screw ends in the center. I had these dampers in my drawer but I don't have a part number or source. The other solution I saw on the web is to insert M3 Flex-Loc dampers (check google images) from the top into the stock dampers and a printed counter-part with a M3 thread from the bottom. Either solution leads to a siffer connection which is required to reduce oscillation.
These are the PID params I currently use - they are not optimized yet but are good starting values. Comments are welcome...
Roll: pwr 60, P 10, I 0.1, D 40
Pitch: pwr 50, P 10, I 0.1,D 40
I bought a brushless gimbal for a Hero 3 (same as this: http://www.ebay.com/bhp/gopro-gimbal) and modified it to hold the original DJI Vision cam. My first project with SolidWorks, so please excuse for flaws in the design ;-).
Some details to the application:
I use an independent GPS tracker which sits also on board of the gimbal base plate.
The PCB is mounted with the parts facing to the plastic, thereby protecting them from contact with the camera.
The sensor is mounted on the flat pad on top of the cam holder with double-sided sticky tape.
The camera snaps into the holder - you need some force to bend the flaps aside, but I was able to put it in and out multiple times without braking the PLA.
I get the power for the gimbal from the camera cable. I made a 3.5 mm 4-pin (important!) extension to the cam and split off the power. The shield carries Vcc and pin 3 GND. To clarify the connector pin-out: The tip and the adjacent ring are for the communication to the cam. The ring next to the shield is connected to Vcc (positive power).
The base holder has a whole which serves to hold the female connector. The camera connects by a rectangular plug. See the images for more detail.
Mounting is critical for success. First, the holder was designed to place the gimbal in a position which brings the center of gravity right in the middle of the Phantom. So, if you have different gear, you'll have to shift the holder. I attached the holder to the copter by stiff dampers (the original ones are too soft) and placed silicone pads between copter and base plate (see images). These pads are critical, as without you'll end up with un-dampened vibrations. I'm still working on this, so maybe someone has a better design?
The space is tight and so the camera sits just a few mm above ground when facing a few angles up. So there's no need to modify the landing gear.
The servo output connects to the RX-Pitch input of the gimbal by ground and signal only (don't connect 5 V). Tilting all the way down is possible.
And finally, here are the SolidWorks 2012 files: http://www.stoeckli.net/?p=124