I made my first caterpillar, the Wooden Oruga, during an artist residency at Orchardton House in southwest Scotland. In some ways it’s the most far-fetched mechanism I’ve ever created. There is a motor at each link connected to a piece of threaded rod. The caterpillar itself is covered with sliding contacts that feed variable resistance to these motors. So it is the shape of the caterpillar that determines the speed of the motors, which in turn changes the shape of the caterpillar. In theory it could work, but in practice it meant trying to balance six continually changing feedback loops. I considered myself quite lucky when, with a lot of coercion, it walked two feet in 17 minutes during its opening show.
Made of steam bent Oak, this is the only digitally controlled sculpture I’ve ever made. I wire wrapped over 50 IC chips including NOR and NAND gates, counters and de-bouncers to control this caterpillar. I didn’t make notes about how it is wired, and all I remember is that if I had one toggle up when another is down, it will short out. But I can’t remember which switch is which and so have been afraid to turn it back on.
This has the exact same math as the Chenille, but instead of a digital circuit, it has a single cam that controls the caterpillar. I love how the shape of the cam can hold more information then a digital circuit. It worked so well that I’ve never turned away from the potential of analogue movement.