Graveyard Automata

Once upon a time, just before the world shut down, I was going to teach a week long class on building automata at my kid’s middle school. That never happened. Eventually I got tired of staring at the quick sample/prototype I’d built for the class, and decided to build it out into something that could live on my bookshelf.

Which mean, building a case for it, so that I didn’t have to dust it, and so that it didn’t get crushed. Along the way things got a little out of hand, and lights got added in, and I learned some hard lessons about how much UV resin shrinks when it cures.

The cams and followers that make the whole thing go. The ghost is driven by two opposing cams that make it go up and down and spin back and forth, while the pumpkin is driven by one snail cam.

I laser cut all the side and top panels with tree silhouettes that I designed, and then I tried to fill them in with UV resin. It ‘worked’, but in some places where the UV resin shrank it pulled away from the edges, and in other places where it stuck it actually warped the frame. Next time I’ll try an epoxy resin and see if that works better.

This is the leaf switch that turns the lights on and off, triggered by a lumpy cam. It didn’t work quite like I’d hoped, and it makes a rather loud twanging sound when it activates, but it does work and it was cheap. It would be nicer to use a microcontroller that faded the lights on and off, but I was trying to keep this simple.