Preliminary Ideas

I've been researching, brainstorming, and sketching this and that, from what kind of movements I want to have and what I can actual accomplish. At this time, I think it's best if I try to plan for everything and as I build I can scale back...

To begin, I'll focus on the head and neck area (I'll also try to get some of my sketches up eventually). The different movements I would want in my ideal WALL-E would be:

Eye Lense Zoom - Inner element would move back and forth and also be able to stop in any position between. This would most likely be accomplished by a low power stepper motor and lead screws.

Eyebrows - This should be a simple open and close mechanism using servomotors.

Eye Tilt (Roll) - Each eye should be able to tilt up and down and stop in any position between. I'm thinking about using servomotors but I'm worried about the torque output vs. the weight of the eyes. Servomotors would be more compact than other actuators but I may have to resort to using lead screws or double pneumatic cylinders connected to a stepper motor which is better described in the next section...

Head Tilt (Pitch, Roll) - The real WALL-E has a ball socket joint at the base of the head but no way to actuate it. Disney's version seems to be using two micro linear actuators in addition to the ball socket joint but I can't tell what type of actuator it is. Others have used a pan/tilt bracket using servos but I want to try and mimic Disney's version using pneumatic cylinders. I'll probably use single acting pneumatic cylinders and connect the air line to another pneumatic cylinder. I want to do this because I don't want to add a compressor... this method would be similar to the syringe operated hydraulic excavator hobby kits they have out there. I'll probably have to add a T joint and valve in case I need to release pressure or recharge the lines. With these three points (ball socket joint, two pneumatic cylinders) I should be able to give pitch and roll to WALL-E's head.. I'll probably integrate the control with an accelerator mounted in WALL-E's nose.

Head Rotation - At the base of the ball and socket joint in the neck, I'm thinking about using a servomotor or a stepper but I need to determine what kind of torque I need for this application. Also, there's not much room in WALL-E's neck so we'll have to see...

Neck - From the base to the ball socket joint, there are going to be three pivot joints. These joints will be controlled using belts and pulleys similar to the a lot of robotic arms. There just isn't enough space to have motors at each joint but if I can fit pneumatic cylinders, I might go with that. With pneumatic cylinders or the belt/pulley method, I'll be able to have a lot of the weight out of the neck and inside the body which is a definite plus.

Well that's that for the head and neck movements... if I can, I want to add at least one wireless camera to WALL-E's eyes but I'm not sure the one camera I looked at will fit inside. It's a common 2.4 GHz 9V camera but with the two glass elements, I don't know if I'll be able to see anything in the end...

In other news, I have a spare Arduino Mega that I could use but I'm thinking about using that for the front solar charge panel and using a Maple from Leaf Labs or Beaglebone for the main controller. We'll see. For the drive system, I'm looking to use two NPC 2212's along with Dimension Engineering's Sabertooth 2x60 ESC. Depending on the final weight of WALL-E, I might have to change that as well.

Well, time to do some more sketches before sleeping...

WALL-E Dimensions

How big should WALL-E be? I know that there are some issues out there with scaling WALL-E to real life objects so let's see how it works out by comparing him to the Playmate cooler.

Assuming the cooler is the Igloo Playmate Elite Cooler (14.88" H x 15.88" W x 10.19" L), I get:

Assuming the cooler is 15.88" wide, it looks like it is smaller than the width of WALL-E's back - perhaps the size between the rubber padding in the corners according to this next image...

... but the tilted height of the cooler almost matches WALL-E's body height. If the cooler is only 14.88" high, it'll never be 17.66" high tilted... hmmm....

Then, maybe WALL-E is a little bit smaller? The Elite's H/W ratio is 14.88"/15.88" = 1.07. There is the Igloo Playmate Pal Cooler (12.0" H x 11.0" W x 8.0" L) and it's H/W ratio is 12.0"/11.0" = 1.09, so it's a tad bit taller with respect to it's width... 

Let's try another image...

Since the reference line (the red 16" line) is at an angle, it should be technically larger than 186 pixels, so any lines that are straight, like the height and the eyes should be smaller than the given number, thus the minus. Anyways, this one is somewhat similar to the previous dimensions, so perhaps it's the cooler that's out of scale...?

Once again, the dimensions are similar (roughly)...

I couldn't find a larger version of this, but the ratio is about 49/38 = 1.29. On the other images, we have ratios of: 1.15, 1.13, 1.08.

From the WALL-E Builders group, their original was 19.25" across the top and 18.625" for the height for a ratio of 1.03. My ratios are: 1.04, 1.01. So, my measurements are in line with theirs.

Let's take one more final look before deciding what to do...

Cooler height to body height ratio is 397/421 = 0.943. My scaled version gave me 14.88/17.66 = 0.843. Their cooler height to depth ratio is 397/245 = 1.62, but since the depth is at an angle, the ratio should be less than 1.62. The actual Playmate is 14.88/10.19 = 1.46, so it works. I suppose that the errors from my line accuracy and perspective issues can lead to large errors. At this point, I'm pretty satisfied with my original dimensions. So, let's begin the fun with some CAD drawings!

My Inspirations

Luckily, there are plenty of people out there who have created their own WALL-E's. There are so many different ways to attempt this endeavor: Disney's own version, papercraft, cardboard, woodworking...

Disney's official WALL-E (obviously without his clothes)

Disney's official WALL-E in action

Papercraft version by Elsocraft

McMaster and Mike Senna's WALL-E's

If my WALL-E turns out just half as good as these, I'll be satisfied... Heck, I'll even be happy with being a quarter as good as these. Looks like I'm going to be broke after this little project.

Day 1 (Well, sort of...)

Inspired by the WALL-E that Disney made, I've finally decided to make this adventure of mine official... and so begins, my journey of designing and building my very own WALL-E. No matter how long it takes, and no matter how much money it costs (well, not too much I hope...eeek), I will create my WALL-E!