
Estonian technology company SprayPrinter—known for its eponymous product that launched last year—has developed a new prototype robot that can scale a building to print large murals. The new device is programmed with a laser-engraving software, and houses a printhead (a component which transfers the printed elements onto a medium) consisting of five SprayPrinters and controllers, which translate the printing commands into signals. The robot is designed to spray five colors simultaneously to create a full-color image.
Recently, the team used the new SprayPrinter to paint a mural by Estonian artist Maari Soekov, onto the façade of a 295-foot chimney in Tartu, Estonia. The mural was created by producing numerous 0.8"-diameter dots which took about 14 hours to complete. The device works by wirelessly connecting to a computer, which converts the mural image into "a text file consisting of coordinates and laser power values," said SprayPrinter's founder Mihkel Joala. The coordinates (G-codes) are then transmitted to the printhead's controller that indicates where and when to release each color. In a video posted on the company's YouTube channel, Joala explains the difference between the new device and its predecessor. "This time we are not using camera feedback [to locate the printhead]," he says. "The computer knows exactly where the printer is by the length of the cable." Using pulse width modulation—a technique for converting computer output into pulsing signals—various pulse widths indicating different colors, ranging from zero to 1,000 microseconds are sent to the printhead's controller as code messages.
The company estimates that approximately 100 new SprayPrinters will be available by the end of this year, and says it will launch a fine-tuned second version in mid-2018.

