Robo Rainbow

This is an invention called Robo Rainbow by the Swedish street artist known as Akay. The device, which is pulled behind a bicycle, features a long, extendable metal arm with six different cans of spray paint in different colors suspended on it. The arm, which is designed to move in a large, sweeping arc, is lifted by a pulley system made up of bike chains and cogs, powered by a hand drill.

A small circuit board featuring radio-controlled servos from a toy car drives the solenoids attached to each spray can, which in turn apply pressure to the nozzles. Both the arm and the spray cans are controlled using the toy car’s radio controller, allowing the user to move the arm in a smooth arc while spraying with each of the six spray cans simultaneously, creating a large rainbow painting within seconds.