In this instructable, I will show you how to make a wooden automata with a "The Little Mermaid" theme. It's a bit of a tedious process, but in the end, it's totally worth it! This automata uses several simple machines: a wheel and axle, an incline plane, and a third class lever. Let's get started!

*In the attached video you can see it in action!

Under the Sea Automata
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Step 1: Gather Your Materials

For this project, you will need:
1/8 inch basswood planks
3/4 inch basswood piece
1/3 inch diameter wooden dowel
1/4 inch diameter wooden dowel
Any 1/2 inch thickness wood

Wood glue

A 3/4 inch hinge with small screws (I got mine from Home Depot and the screws were in the box)

1 inch thickness plastic
Assorted paints/paintbrushes

Step 2: Gather Your Tools

For this project, you will need:
A laser cutter
A milling machine
An electric handsaw
A drill
A hammer
Brads

An X-Acto knife

A small screwdriver

Inkbot App

Step 3: Cut Out Your Small Pieces

First, use Inkbot to make an SVG file in the shape of the characters (Ariel on a rock, Sebastian, Flounder) and the decorations (brain coral, seaweed, anemone).
Next, import it to your milling machine's software. Using the milling machine, cut out the shape of Ariel on a rock from the 3/4 inch basswood. Now, import the file to your laser cutter and cut out everything, including the decorations from the 1/8 inch basswood. If your basswood is only 4 inches wide (like mine) you might have to cut Ariel in two separate pieces. Afterwards, cut out seven 2.5 inch diameter cams from the 1/2 inch thick wood using the laser cutter.

*The Ariel on a rock pieces should be about 5 inches tall, and the other pieces should be to scale with her (all of them are various amounts smaller)

**After you cut the Ariel pieces, break off the fluke of her tail from them. Glue the fluke pieces together and the body/rock pieces together separately.

Step 4: Paint Your Pieces and Make a Background and Sign

Using paint (I used acrylic) and paintbrushes, decorate your laser cut pieces to the best of your ability. If you are having trouble painting the small details, just print a picture of the character/decoration and glue it to the wood.

Next, use an X-Acto knife to cut a 16x4 inch piece of 1/8 inch thickness basswood. This will be your background. Paint it to look like an underwater scene.

Then, use an X-Acto knife to cut a 10x4 inch piece of 1/8 inch thickness basswood. This will be your sign. Paint it with a title and fitting scenery. In the second picture attached, you can see how I painted my sign and background. Of course, yours can look however you want it to. This also goes for the first picture; paint your pieces in whatever way you like.

Let all paint dry.

Step 5: Cut Pieces for the Structure

Now, use your electric handsaw to the 1/2 inch thickness wood.

You will need:

a 16x4 inch piece

two 5.5x4 inch pieces

Now, cut a 16x4 inch piece of the 1 inch thick plastic.

Next, cut a 19 inch piece of the 1/3 inch diameter dowel

Step 6: Begin Assembling the Structure

Lay the 16x4 inch wood piece flat. Secure the 5.5x4 inch pieces perpendicular to it on either side using the brads and hammer. Next, use the brads and hammer to secure the 16x4 inch plastic piece on top of the 5.5x4 inch wood pieces. All pieces should be flush.

Then, drill holes through the middle of each of the 5.5x4 inch pieces to fit the 1/3 inch diameter dowel. The holes should be loose enough that it can turn freely. Now, 3 drill holes through the plastic to fit the 1/4 inch diameter dowel. They can be wherever you want depending on where you want to place your three moving pieces (Ariel's tail fluke, Flounder, and Sebastian). Just make sure you leave room between the holes for your characters. Next, drill holes through the center of three of your cams. These will be your cam followers. After that, drill a hole through the center of another cam. This will just be a centered cam. Then, drill off-center holes through the remaining three.

Next, push the 19 inch piece of 1/3 inch diameter dowel through one of the holes in the sides of your structure. From there, push your off-center cams onto them. To make Ariel's fluke go up and down, push one offset cam in the desired place on the dowel. To make Flounder go up and down and turn left and right, push two offset cams onto the dowel. One should be at its highest while the other is at its lowest. They should be near each other (about an inch apart). To make Sebastian spin, push the centered cam onto the dowel. All of these should be under their corresponding holes in the plastic.

Step 7: Attach Ariel's Fluke to Her Tail

Screw one part the hinge onto Ariel's fluke and the other onto her tail. Now her fluke should be able to move up and down.

Step 8: Make the Cam Followers

Using the three remaining centered cams, make your cam followers. Put tape at the bottom of each one to cover one end of its hole so glue won't seep out later. Next, cut pieces of the 1/4 inch diameter dowel for each one. The piece for Sebastian should be as long as the distance from your main dowel to the top of your plastic piece. The piece for flounder should be from the main dowel and past the top of the plastic piece to whatever height you want him to be at. The piece for Ariel should be from the main dowel to her fluke when you place her on top of the plastic. Then, put each piece of 1/4 inch diameter dowel through its corresponding hole on the top of the plastic. Fill each cam follower's hole with wood glue and put them under the pieces of dowel so that the dowel will be glued into the cam follower. Let each cam follower rest on top of its cam(s) while the glue dries. While you wait for the glue to dry, you can paint the plastic to look like the ocean floor.

Step 9: Finish Assembly

Glue Ariel onto the plastic so that the dowel piece for her is right under her fluke. Glue Flounder to the top of his dowel piece. Glue Sebastian to the top of his dowel piece. Next, glue the background to the back of your plastic piece and glue the sign on the front of it so it hangs down in front of the cams. Then, glue all of your decorative pieces onto the plastic.

Step 10: Enjoy Your Automata!

To make Ariel's fluke go up and down, Flounder go back/forth and turn right/left, and Sebastian spin, all you have to do is twist the main dowel. That makes all of the cams spin.

For Ariel:

The offset cam spins around and lifts the cam follower as it turns. The dowel attached to the cam follower lifts Ariel's fluke.

For Flounder:

The offset cams spin so that each one turns the cam follower to one side a little before the other takes over and turns it to the other side. Because the cams are offset, he also goes up and down because they are pushing the dowel up as they spin.

For Sebastian:

The centered cam spins the cam follower in circles. This makes Sebastian spin in circles with it because he is attached to it by the dowel piece.

I hope you enjoyed this instructable and found it easy to follow! Thanks for reading and good luck!