DrawBot Automatically Spray Paints Giant Murals

Murals are a great way to add style and culture to an otherwise drab building, but painting them is expensive and time-consuming. A large mural will take an artist many, many hours to complete — often while working out in the heat. There is no denying the artistic quality of a completely original, hand-painted mural. But, if you’re satisfied with an existing piece of digital art, Edwin Dertien and Janwillem te Voortwis’s DrawBot can automate the process.

DrawBot is a huge V-Plotter robot, which rides on two bicycle chains attached to the top corners of the wall being painted. Sprockets driven by large stepper motors control the lengths of the chains independently, so the hanging DrawBot can be positioned at any X/Y coordinate on the wall. There are eight cans of spray paint arranged radially around the robot, and those are activated by RC servos that push on 3D-printed levers clamped onto each can.

The steppers and servos are controlled with two custom Arduino-compatibleATmega328 boards. A Processing sketch running on an old Panasonic Toughbook converts an image into plotter coordinates by color, and sends the DrawBot on its way to spray paint each “pixel” of the mural. DrawBot was successfully demonstrated at a maker festival, where it was used to print large mural reproductions of the Mona Lisa. A single 3 x 4 foot art piece takes more than 2 hours to complete, but that’s better than having to paint it yourself.