Automata
by Andy Baird

Cat and butterfly picture

An automaton can be described as a mechanical toy or a mechanized sculpture. To me these whimsical devices represent the perfect intersection of mechanics, art and humor--a good place to be for someone like me.

The pictures on this page are of are wooden automata that I've made. For more (many more!) of these amusing devices, see the Cabaret Mechanical Theatre website. It was this site that inspired me to begin making automata--thanks, folks!

My first automaton was this "Cat & Butterfly." It's a simple concept: the cat lunges at the circling butterfly, but never quite succeeds in catching it. Although this is a simple device, it took me about a month to make, because I did a fair amount of experimentation on the mechanism before I got it working the way I wanted it to.

Cam mechanism

The cat's body is lifted up by a pushrod (a 1/4" dowel) driven by a cam about 2" in diameter. I found that my first version, in which the rounded end of the rod rode against the cam, had too much friction, so I added a small wheel (made from a thin slice of dowel) to the end of the pushrod.

Pinwheel gears

It was necessary to slot the pushrod and put a pin through it in order to prevent the wheel from turning sideways to the motion of the cam. You can see the bent-down end of the pin (a piece of wire, actually) protruding from the block above the cam.

The butterfly is mounted at the end of a piece of wire (a guitar string) and made to revolve by a pair of pinwheels or lantern gears. Making these was guesswork, since I had no guidelines as to how many pins to use, how far apart to space them or how long to make them. After some experimentation, I ended up with 2" diameter disks having 12 pins each. The pins I made from small brads. I predrilled the holes and pushed the brads in, then clipped off the points and secured the heads with epoxy.

When the cat's body is raised (pivoting on the center of the hind paws), the front legs raise from the base to snatch at the butterfly. This motion occurs thanks to a wire linking the hind paws (which are fixed to the base) and the shoulders of the front legs. As the body lifts, the wire linkage pulls the shoulders back, raising the front paws skyward.

Leg linkage

The butterfly was copied and reduced from a coloring book; I colored it with felt-tip markers and laminated it in clear plastic.

Butterfly