In this Instructable, I'll show you how to make a simple automata/mechanical toy in the theme of the popular fairy tale Little Red Riding Hood. The mechanism consists of a crank to move the Little Red Riding Hood character, and a drop cam to raise the Wolf, and the final effect is that Little Red Riding Hood will move back in fright every time the Wolf raises itself above the bush. A good understanding of mechanisms and woodworking should easily get you through this Instructable.
Here's a parts list for what we'll be making:
Little Red Riding Hood (3D Printing) Approx. 60x30x30mm
Wolf (3D Printing) Approx. 40x20x30mm
Top (CNC) 76x200x12mm
Sides x2 (Cut) 200x100x12mm
Bottom (Cut) 76x200x12mm
Back (Cut) 200x200x6mm
Wooden Dowel (Cut) 5x500mm
Wooden Dowel (Cut)8x500mm
Bush (CNC) Approx. 100x40x12mm
Crank Piece x2 (Cut) 40x15x6mm
Rail Sides x2 (Cut) 10x100x6mm
Rail Tops x2 (Cut) 20x100x6mm
Sled Piece x2 (Cut) 20x20x6mm
Wire (Cut) 180mm
Drop Cam (CNC) Outer Rad. 45mm, Inner Rad. 7mm
Scrap Thin Acrylic/Wood
You'll also need a drill, 5, 6, 8, and 10 mm drill bits, a mallet, hot glue, and some sandpaper for finishing.
Step 1: Cut, CNC and 3D Print
All you need to do to start off your contraption is get all your parts cut or printed, and sand them smoothly.
Step 2: Create the Box Using Doweling
Using 90 degree corner clamps if it helps, drill 5mm holes into two adjoined pieces, and then hammer in a short segment of dowel. This will help because you can easily take it apart later to edit mechanics.
Step 3: Drill Holes
Drill the holes for the driveshaft and the wolf to move. Use 10mm drill for the driveshaft, because we'll be using thicker dowels so it is stronger. The wolf can be mounted on a smaller 5mm dowel, so use a 6mm drill in order to make it run smoothly. Drill also adjacent holes in the crank pieces and in the handle piece (which can be scrap wood).
Step 4: Build the Mechanism
Glue 2 pieces of about 100mm of thicker dowel into your crank pieces. Next, join the 2 crank arms with a thinner, 10mm dowel. Glue everything firmly. Slide on the drop cam to where you drilled the wolf hole. Align it so that when the crank is backwards, the drop of the cam is at its climax. Glue it tight. Using the wire, make a loop, and fasten it to the sled, which is the 2 sled pieces glued in a T shape. Finally attach the other end of the sled driver to the crank.
Step 5: Build the Rail
Put the smallest rail sides about 22 mm apart, directly under the slit where the puppet arm for Little Red Riding Hood will be. Glue them down, and glue the bigger pieces on top so that they create an overhang that clamps down the sled. Make sure the sled can move smoothly in the rail.
Step 6: Insert the Mechanism
Put the mechanism into place in the box and gently hammer it closed. Test if everything works once it is done.
Step 7: Paint Your Pieces
Give all you pieces that are important some flashy colors, because it will look cool and more functional :).
Step 8: Add in the Characters
Add in the characters, secure the handle with glue, and watch the magic happen!!