I'm trying to develop a low cost intervalometer that works with older Nikon Coolpix cameras and others that use a serial interface. The reason I want to use these cameras is that I'm looking for a system that could cost less than $100 for the camera and controller. This would be used for a time lapse documentary project that would gather time lapses of various places along with voiceover from someone for whom that place is significant. It would be necessary to either be able to both build and distribute a large number of these and provide simple instructions for those who are so inclined to build their own.
What I'm wondering is where I would go to learn about this sort of serial protocol. I can wrap my head around making a simple connection to trigger a shot, but I know nothing of serial protocol. I did find this:
But I don't really understand any of it.
Any thoughts would be greatly appreciated.