Taking Shape!

Finally, it's really starting to take shape and start to resemble a snake! A few updates from my last post include: an additional segment and an extra servo reinforcement that hooks the back of the servo into the rotating chassis, as well as the horn. This allows for the force/stress to pass through the snake through two points, and not just the one that had originally been planned. This addition greatly improves the structural integrity of the snake. So far, I have two joints in the X direction and one in the Y. After one more in the Y, I should be able to get some very basic motion patterns down, but nothing as good as the final product.

I'm getting to the point where I'm comfortable enough with the design that I'm getting ready to get a nice big sheet of aluminium for the chassis pieces, and weaning off the scraps laying around the garage. Also, I'm getting to the point where more servos are going to be

necessary, and not just the 4 I got to start with.

I'd like to make a quick thanks to Michael Morrissey and Robotics and Beyond for providing me with the chance to do something as cool as this. Without their help, I would never have been able to do this.

Now, here's some more photos of the status of the project so far:

A shot of the segments each twisted at 90 degrees so you can see the different aluminium chassis pieces connected together.

The segments angled at slight less angles than before.

Another 90 degree shot from a different angle.

All the segments in-line.

Another shot of everything straight together, and you can see how the different pieces interact.

Coming Together

12/3/09

This project's no longer just thoughts and crude drawings scribbled out on napkins, or even the CAD sketches I've put together. As of now, something worthwhile exists. It's not too complex yet, seeing as I only have one joint of the snake flopping around on my desk, but, it's there, it's moving, and it's working just as planned. It shows that it IS all possible, and I expect to have up to 4 sections put together within the upcoming week. Here are a few pictures of the work so far:

Here's a preliminary shot of the first round of work, with just one servo and one chassis mount

Here's another shot of the second servo mounted into place, with the top chassis mounted in too.

A shot from the side

Here's a shot of the two servos without their top chassis piece holding them together.

blast off

So, the snake idea has been starting to take shape, despite the fact that it still looks nothing like one, and won't for a while at least. However, I did manage to overcome my first expected problem: getting a live data feed from the computer, through the basic stamp microcontroller and to the servo controller, in turn moving the servos. It's not a 2 independent axis sine waves working together to coordinate a snakes movement like it will be in the future, but rather, a single servo with 2 positions, chosen by whether the the mouse button is depressed or not. However, the hard part has been taken out of the way, and the more complex multiple servo control should be relatively easy.

Hardware wise, I've just come out of the crude "folded index card mockup stage", and have entered the stage of using real materials, including aluminium, plexiglass, and lots and lots of screws. It still resembles no snake you have ever seen, because it's literally just part of one of the many segments the finished product will have.

I've included a few pictures to document my progress:

A Close up of all the electronics powered up and ready to work

Circuit boards, power sources, and servos

Just the electronic equipment, before being hooked up

A quick view of just some of the code used for the most basic motor functions.

A servo and its aluminium mount: just a small part of one of the many sections of the entire snake.