the jaw most likely opens all the way every time, i work alot with pneumatics and position control is alot of work and takes more solenoids, so he probably went with just a single movement controlWow !
If that is pneumatic, it is incredibly fast.
It is hard to tell, but can anyone tell if there is partial mouth opening? It almost looks like the mouth always opens to the max or at least appears to be heading that way. Like the movement impulse is stopped. I got a cheap skull in candy tray from K-Mart. $7.00. The eye movement is basic and the movement is really simple. Just a motor with a string that winds up on the shaft to open the jaw and a spring to pull it back. I think it is controlled similiar to the circuit Doc shared on his early skull.
So, the feedback cylinder is connected to the atcuation cylinder to provide feedback to the fancy valve? Does this mean compliance technology can be implemented with pneuamtics? Wow! I was with you...I thought that was for hydraulics only too. Heheh..."retardedly expensive".Just found this site and all the questions everyone had so I thought I'd jump in and answer. The skulls are made by Gemi corp. as a cheep prop. You can usually find them before Halloween at CVS pharmacy for about $14.00. They use two standard DC hobby motors. One for the eye movements, and one for the jaw. Both setups work but would be very unreliable for theme park use and abuse. But hey, 14 bucks for a skull with all the parts works for me. I used very small "bimba" brand single acting spring return air cylinders to replace the jaw motor and haven't had a breakdown now for two years. I'm gearing up for some crazy stuff, including work on the Wizard of Oz exibit for "Great Explorations" in St. Pete. Also picked up a super fancey (and retardedly expensive) servo pneumatic valve from Enfield Tech.(Enfield Technologies - Servo Pneumatic Proportional Control Systems) at the IAAPA show. When used with the newer position feedback air cylinders, it makes a fully closed loop position controller that can drive an air cylinder just like a servo motor. I always thought you had to go hydraulic for that kind of smoothness and speed controll. They are even faster than solinoid valves. They can open fully five cycles in both directions faster than a solinoid valve can just open once. But they are almost $600.00 each (without the driver that costs another $550.00) but this is how Disney is driving their newest line of charactors. Literally, turn the controll dial (just a 10K pot) and the air cylinder will follow your every movement at any speed. Cool stuff. BTW, the MIDI controllers I used for the bone tones was the Highly Liquid MSA-T (Highly Liquid: MIDI Retrofit & Decoder Kits, DIY Electronics) designed by John Staskevich. But he has a new one that I had some input on the design called the MD-24 that has 24 outputs that can be set for logic or PWM servo signal out for less than $50.0 in kit form, and if you order one, tell John that Bill sent ya! He did the software for my standalone MIDI show player, great guy and MIDI master!
Hope I answered some questions, and don't have a problem sharing because, remember grasshopper, anyone can build an animatronic charactor these days. Only the ones that are PROGRAMMED WELL will stand out in the crowd.
Good luck all with your respective projects,
Mindshaft Music Inc.