Polka: A Water-jet Printer for Painting on the Grounds

We propose a method for controlling a device that draws letters and illustrations on large, flat surfaces. Similarly to conventional inkjet printers, the device ejects a volume of water from its nozzle, with the water droplets then forming dots on surfaces such as soil, concrete, and sand. Both the direction of the nozzle and the water pressure can be controlled to enable the device to draw arbitrary two-dimensional patterns within a semicircular region with a radius of six meters. The device can draw letters and illustrations. We have investigated the pressure, the shape of the nozzle, and droplet size in order to avoid further division of the droplets into even smaller droplets while traversing the air. In this paper, we introduce the mechanism of this device and demonstrate how a user can take advantage of this new drawing tool.