Karen, I think I understand your problem, as I do this sort of thing
a lot. As I see it there are several issues: easy to use, both set up
and in actual use, unobtrusive, not too expensive.
You need to choose TV based or computer based. For this discussion I
will go with NTSC TV based systems. Most schools have large carts
with TVs and VCRs, so you can use that to display. Video projectors
work well for larger audiences, but the logistics of setting them up
sometimes get in the way of the demonstrations. They can be used
with a computer web camera which is small and very inexpensive, as
could a laptop with a large external display. If you would like to
explore this option, let me know.
So, we have settled on TV system and a TV set up near the
demonstration, now we need a camera. Again, there are several ways to
go: Camcorder small fixed video camera like a security camera, a
document camera system - also called a presentation camera,
visualizer. Unfortunately, most of these are like a flat glass
topped box, a back light and overhead illuminated system which at
best, is in the way of doing any jewelry manipulation, and cannot be
hammered on and is intrusive. Another type is basically a camera on a
flexible arm. I have two Canon Vizcam cameras that are higher end
flexible arm systems. Presentation cameras range from $100 to $600 on
eBay, to several thousand dollars new. I highly recommend flexible
arm type. They are VERY simple. Plug them in to power and the TV and
you are good to go.
The other alternative is to get a camera, or camcorder and attach it
to a mount that will capture the demonstration area you wish to show.
These can be a pain to set up, but can be very effective because you
can zoom to just the right size with the camera well out of the way.
the mounting system could be cumbersome or complex, from overhead
mirrors, or expensive commercial tripods with horizontal extensions,
to pipe mounted to the jewelers bench. This can be an attractive
solution to a fixed bench demonstration area, but in my experience
you will be demonstrating various techniques at different places in
the classroom and on the bench.
Good luck, I think you will find it well worth your time to do this.