I decided upon using my Canon EOS 500 as the new camera for the rig, mainly because it had a nice wide angle lens on it (28mm) and was relatively fast at f3.5. It was also quite light for an SLR and has an electronic remote shutter port. However it was also quite an expensive piece of kit, even though I did buy it off a mate a few years back. So I wanted the camera rig to afford a degree of protection. Most rigs I have seen on the Net are very exposed, instead I wanted to conceal my camera in a protective dome. I also wanted to incorporate on the rig a small CCD camera with a microwave link for transmission of the cameras view to the ground. For this I found a company called RF Concepts who were able to supply me a video sender and receiver for about 100 pounds, a picture of the kit is shown below.

The B/W CCD camera I used is available from Maplin Electronics for around 30 quid. Both the video transmitter and the CCD camera require 12V, making the power supply for this part quite simple. The receiver on the other hand requires 6V. I did think about using a voltage regulator, but settled on an extra 6V battery pack. The radio control gear that I had available was a simple two channel system, so it was decided that the pitch of the camera would be fixed at around 30 degrees to the horizon and one channel would control the pan while the other controlled the shutter. I know it would have been nice to have an extra channel and use tilt as well, but that may be a future project...

A lot of people have used indirect servo drive for the pan function, but for simplicity (and I hope reliability) I went for direct drive, with the servo converted to full 360 control. Using direct drive does have the unfortunate side effect of making the camera rig plummet to the ground if the servo horn falls off (uses a Jesus Bolt, so called because you'll be saying that when it breaks..Jeeessuus...Bit of an aviation term, but seems appropriate!). So as a safety precaution I made the picavet cruciform with an extra lower disc which sandwiched an annulus disc attached to the rig. This way, if the servo breaks it will still be captive. It also prevents too much stress on the servo stem. This is shown below:

The dome to hold the SLR ended up being a small food mixing bowl with various cut-outs for the lens, the CCD camera and also a couple of holes so the camera's LCD is visible and the function dial can be turned. The first job was to attach the camera to the dome, which cable ties seemed to be the best choice. The video transmitter is attached to the flat portion of the bottom of the bowl.

The rig was basically made into three parts. These being the dome part with the camera and video transmitter on it, the receiver board with the servo for the shutter release, and the top pan-servo section which also contains the batteries. The receiver board fixes to the base plate of the camera through the tripod socket. The shutter release servo simply swipes its servo horn onto two micro switches connected to the shutter port, the first sets the cameras exposure and the second fires the shutter. Also on this board is the CCD camera which sits to one side of the main camera lens. In addition there is a 15 way connector which the top pan-servo assembly plugs into, battery power and servo connections are fed through this.

The top pan-servo assembly is basically a circular plate of hardboard, with the pan-servo in the centre. On one side of the plate is the picavet cruciform structure, while in the reverse side is the receiver and video battery packs. The 12V battery is a custom made all soldered pack (made from AA batteries) done so it fits into the gap at the rear of the camera when the whole unit is assembled. This does have the disadvantage of having to solder up a new pack every time they go flat, although I am considering replacing it with a Ni-Cd pack. Also on the board is the power switch, concealed under the picavet system to avoid accidental switching.

The whole system clips together using 4 bolts to form, what I think, is quite a neat KAP system. The biggest problem from a KAP point of view is the weight, it weighs 1.8kg. I thought this may make it difficult to lift by the kite. The Flowform does have problems in anything other than a stiff breeze, but the Stratoscoop doesn't flinch!