A Goldfish Controlled Hammer That Rotates Around a Semicircle Smashing Tiny Furniture

Maker and artist Neil Mendoza has created the Fish Hammer, an awesome contraption where a hammer is controlled by a goldfish named Smashie. As Smashie swims around in its tank, a webcam tracks the fish’s position and moves a hammer that drops and crushes tiny furniture “based on the slow rotation of a cam that the hammer rests on”. Mendoza showed how he built his Fish Hammer device on Instructables.

People love to break ocean stuff. The Fish Hammer empowers fish to break people stuff.

As Smashie swims around the aquarium, his position is tracked with a webcam, using software written in C++ using openFrameworks and OpenCV. The hammer follows him around the tank on a carriage powered by an Applied Motion stepper motor. The software calculates the velocity the motor needs to be moving using a PID algorithm that takes the motor’s encoder position as input and gives a velocity as output. This velocity is then sent over UDP to the stepper motor. The hammer head drops based on the slow rotation of a cam that the hammer rests on. (read more)