I hope there's still some people floating around on this board, since it looks like it's been a few years since the last post.
I've endeavored to attempt to create remotely controlled animatronic dragon head. I've already completed an eye mechanism based on a smartly design framework available to anyone with access to a 3D printer from Thingiverse. I've begin modeling the base structure for the head that I'll be covering in faux leather to give it some added realism, but I've yet to figure out how to do a mouth.
I'm assuming a single servo should do, but I can't seem to find any good, clear examples of the mechanism to open and close with the servo. I'm certain I'll have to come up with some custom way of attaching it to the base plate of the eye frame (you can get a better idea of how that works here).
If anyone has any good resources, hints, tips or ideas, I'd really appreciate it.
Have you seen the Organic Mechanics video at Stan Winston School? Rick Lazzarini shows how to make a very simple servo cable controlled mouth mechanism in the video.
The most important thing with a mouth mechanism is to get the position for the jaw hinge in the right location and then it's a simple matter of getting the right servo and leverage needed to make it move.
I think I may have found a solution, but I haven't tested it yet.
First, I've added vertical supports and slipped in a threaded rod for a pivot. I put a servo on the rear of the eye mech and plan to attach it to the rear of the jaw for basic up and down motion. There's probably more than a few factors I've missed, but the nice thing about 3D printing is I can just shoot another part out if I'm wrong. Here's some renders:
Yep, that should totally work. Depending on the size of the head you could need to use a pretty strong servo due to the high leverage ratio. You could offset this by installing some helper extension springs to act as a counterbalance along the back of the jaw.
So far, so good. I'm not getting as much rotation out of the server as I expected (PPM signal range limitation of my controller), so I'm going to be cheating it by running it through an arduino (which allows me to add a few other bells and whistles). The leverage doesn't seem to be causing any problems. That said, this is still just the plastic frame without any skinning, teeth or foam tongue, but I'm hopeful.