This study examines how photoluminescent smart materials might be used to create a new kind of device that does not need any electricity. The project, called Ball Wall, is an interactive surface that consists of hundreds of luminous spheres. Ball Wall allows you to draw or write on its surface at night, with the sweep of a hand, using each sphere as a pixel.

Every sphere is mounted with half of its volume embedded in the wall surface. During the day, the hemisphere that’s exposed to the Sun is stimulated, and glows for many hours after dark. The hemisphere that’s in the wall remains unaffected by Sunlight and does not glow. Therefore, at night, as one sweeps their hand across the surface, the glowing balls turn into the wall, while the dark hemisphere turns toward the surface. Our eyes read this contrast as a mark on the surface. Fading into darkness overnight, the rising Sun resets the luminous surface.

The construction of the demonstration prototype included drilling and filling 426 spheres with three coats of primer and photoluminescent paint, sanding, plugging, and mounting them. The photoluminescent coating is amongst the brightest formulations that are available, and was provided by our collaborator, Performance Indicator / Canopy Defense.