Tag Archives: backbone

Talking Birds, Part 3

There has been quite a bit of head scratching over the last two weeks. Somehow the design I scratched on a Post-It Note wasn’t exactly to scale. I was close, though. Damn close. I’ll continue to use the Post-It Note method.

The plan was to mount the servos along the backbone such that there could be levers that push the mouth, neck, and wings. Moving the mouth turned out easier than I thought. There was enough space in the head of the puppet place a servo:

Mouth servo

The neck and wings still presented a problem. The neck levers had to pass over the wings servo and shaft. In order to make the geometry work out, the servos had to be moved to the very rear of the puppet:

Neck servo and wings servo

Actually, they end up hanging out the ass of the bird:

Measure twice. Cut once.

Unpleasant, I know.

At this point I am in total disbelief that I got it this far. I hooked this thing up to my new Northlight Systems servo controller and the thing actually works! Sure, this is a simple machine and I pretty much knew that the pieces could move by pushing them with my fingers. Still, there is always that chance that the thing could somehow go nuts and destroy itself.

I’m easily entertained by mechanical systems. The is an obvious byproduct of working in the software industry. I have issues with having spent my entire career never having made a product that does something. Maybe I wouldn’t think about it so much if I were an accountant or policeman. As an engineer I’m very much jealous of people who get to make things like cars or bombs. Maybe not bombs. Let’s consider it an extreme exemplar.

Anyway, now that we have one working, all we need to do is copy it…

Talking Birds, Part 2

Truth be told, I like planning these projects much more than assembling them. I learned several years ago that manufacturing things is hard. In fact, the smaller the parts the harder it is.

Conceptually, the parts of the bird go together like Lincoln Logs. Objectively, it’s really hard to make anything out of Lincoln Logs that you can fit up the butt of a hand puppet.

It would be great if only my local hardware store would stock a myriad of little brackets in varying sizes; tiny little metal shapes that would have no use in home construction. But they don’t.

I know. Some hobby stores carry some Erector Set like things for mounting servos or other small items, but they often get $4 for a ¼” L-bracket and that just doesn’t seem reasonable. Even at 50¢, you have to ask the question “How long will it take me to make these with a hack saw and a length of L-bar or U-channel?” If you cut the parts yourself, you can have any size you want for very little money.

Here’s an example:

Neck joint

How to create a neck joint at the top of the backbone? It needs to be at a certain angle and have a certain range of movement. I’m not sure how it should be done either. I think that a rod end affixed to the end of the L-bar should work.

And yes, I’m totally guessing at the angle.