“I thought it would be fun to pit a large metal machine against a small fragile object,” says Mendoza. “When people look at the egg darting around on a long stick to avoid the pendulum they seem to see it like a Looney Tunes cartoon with the big lumbering pendulum forever chasing the egg but never quite catching it.”
Mendoza created the piece, Eggsistential Angst, for a group exhibition called Rare Meme. The pendulum is made from CNC’d aluminum, as is the quick-spinning reaction wheel on the end. The pendulum moves freely; all the motion comes from the spinning of the reaction wheel, similar to how satellites change their orientation. The momentum change of the pendulum is driven (inversely) by the momentum change of the spinner, which is in turn driven by an Applied Motion SSM23IP-3EG StepSERVO (a hybrid stepper/servo), which is controlled by an Arduino Due.
Meanwhile, the same Arduino controls the placement of the egg. It sends the angle of the pendulum to an openFrameworks program running on a computer, which calculates a position at which the egg will miss the pendulum (or vice versa) and commands the stepper motors in that part to move the egg appropriately. It carries on indefinitely, alternating between balancing and swinging freely, says Mendoza.
It’s just an egg placed in a vulnerable position, but my favorite part is the video editing, how it builds suspense to the end and… well, take a look. It’s only 55 seconds long.
Process and prototype photos: