This project is for kite aerial photography. The idea is to hang a camera from a pendulum. But any swing of the pendulum in line with the kite gets translated to small movements in the pan motion of the camera. Check out the video (music by yours truly).
I usually have the camera take pictures every 3 seconds using CHDK. To use the rotator, just rock the line back and forth till the camera points the way you want. You can also just wait and it tends to go around eventually.
It's important to adjust the kite line bracket to match the kite line angle before sending it up, since if it's not balanced, it won't be possible to get it to turn. The angle can be off a little but not drastically. If your kite is up-again-down-again, choose a different site, day, or kite. Getting the kite higher can also improve its behavior.
For hardware, I used a nylon threaded rod 1/4"-20, two feet long, a lock nut on top, then a bent washer (the hex hole in the top was the wrong size. I may fix it eventually), then a jamnut underneath, then the toothed ring, and an undersized washer (actually #8 with a 1/4" hole drilled) on the bottom of the toothed ring (this may be done in plastic someday).
To attach the kite line hanger there is a wing nut, bolt and washer to help adjust the angle. I may swap out nylon for some of the hardware.
For the lower part, I bent some aluminum and added wing nuts and bolts. I tapped the aluminum to save some nuts but this is not necessary. I have a captive 1/4"-20 wing bolt for the camera mount which I made by filing away the threads on the lower part and tapping the hole.
Alternatively, for the lower part you can use the bottom holder for the smartphone rigs, also in my shop.
The biggest drawback I've found is that the threaded rod is a bit springy and not very stiff. Sometimes this improve things but more often it doesn't. It's fully functional now, but could use the improvements I mentioned. Don't leave it in the sun and check it for cracks frequently.
My camera is a Canon S95 and is pretty light (7 oz, 200g). I wouldn't recommend this rig for anything much heavier than that.