BREATHING MECHANISM 2 LOOPED

That's a very simple idea. Anyone could build this and one could even make a remote controlled version where a servo turns the screw. The wingnut would need a lot less friction for this but it's not impossible to overcome. This way there would be no need for holes in a character either unless the servo somehow malfunctions. Thank you for this idea.

Thanks everyone for your kind comments!

Vortex42, VERY perceptive comment! That was an issue in my mind when designing it, which I managed to solve - it's not so clear on the videos (nor on my original blog entry - I'll have to change that), but epoxied to the wingnut is a piece of square plastic that fits snugly inside the frame (but not so snugly that it impedes the sliding action of the wingnut) in such a way that it prevents the wingnut turning.

Only issue I can see is if the wingnut turns slightly it will miss the angled pieces... Is there a way for you to nsure the wingnut stays aligned. Other than that I'd say it looks like a great system! Nice work!