The PETtacle

If you follow me you might have noticed that I've been using a lot of plastic bottles lately. I made stuff out of them, like this flask for example. But also the other thing you might've noticed that more than often I don't have a use for the bottom parts of the bottles...

Their day has come.

We all know that plastic bottles are THE engenering material of the future and all the robots will be made out them and other trash. So... there's a bunch of plastic bottle bottoms. They all are different so I start this project with sorting them. I use manufacturing markings on the bottom to distinguos different kinds.

The second thing I do is trimming bottoms that are a bit too high. The shallower parts have greater range of movement in the finished tentacle

Then the bottoms get washed and rinced to be freed from the gunlky residue which usually there.

Holes are made in each bottom to let the tendons through. I used soldering iron and I've been putting the very next bottom over the previous bottom too ensure the holes were aligning.

Eventually I went through a few options for tendons. This twined rope was just something I had under my hand so I used it.

For the basis I used this piece of plywood, where I drilled 6 holed, despite needing 5.. .because I'm a genius.

A piece of a broom goes agains a large hole in the center and being rounded where the plastic portion is it forms a sort of a ball joint.

The first testing proved the concept working, There still were some changes to be made.

The previous rope I used for tendons, although providing a decent movement was too week and tended to tear and snap, so I changed it for this loundry drying twine.

It barely worked.

The rubbery coating was constanly catching on the hole edged and the whole thing barely moved even after smearing everything with machine oil.

So eventually I found a roll of grass trimmer line and as you will see later it worked the best.

The next step was about making this thing that holds the tendonts and moves them.

After doing some advanced engineering I've cut a circle out of plywood. Then I drilled 5 holes for the tendons. Then ways were drilled to the holes and threaded to accomodate the bolts. And the central hole was made to put the broom handle through.

After assembled - it worked. It made unreasonably happly.

But...

I feel it can work better, although I don't quite know how to achieve that. Basic concept is there and it looks like the further improvement will be achieved through figuring out and twicking smaller aspects. Also this is Mark-I of the PETtacle. Mark-II should be longer, stronger and having a manipulator.

So yeaqh, there's that, this is it for today, thank you for your attention and I'm out.