Silly Putty Pan Mechanism
The silly putty pan mechanism, originally developed by Simon Harbord, uses a twisted rubber band attached to a hook that runs through a volume of silly putty. The silly putty controls the spin of the rubber band, giving a slow, controlled spin.
@mathew and I have been developing a pan mechanism using this concept, that is made using hardware and a few custom components that can be laser cut.
As the video demonstrates, there are some inconsistencies in the turn speed of the rig due to friction. There is also a static friction issue, causing it to get stuck at certain points. How might these issues be resolved?
Another option for electronics-free panning is the jerk pan mechanism, developed by @cfastie. This is a simple and effective way to reorient the camera after it has been sent up the line.
A third solution is a wind or wind-up powered mechanism, as demonstrated here.
This mechanism is very effective in that it is both a pan and tilt mechanism in one. The downsides to this mechanism are its complexity and weight. More info on this mechanism can be found here.