The “Programmable Matter”
When was the last time you repainted your car? Rework your collection of coffee cups? Did you give your shoes a colorful facelift?
You probably answered: never, never and never. You may think that these difficult tasks are not worth the effort. But the new system for changing the color of “programmable matter” can change that with light.
C researchers have developed a way to quickly update images on object surfaces. The system, called “ChromoUpdate”, pairs an ultraviolet (UV) light projector with elements covered with light-activated dye. The projected light changes the reflective properties of the dye, creating color new images in just a few minutes. Advances could accelerate product development by allowing product designers to search for prototypes without being overwhelmed by drawing or printing.
ChromoUpdate “takes advantage of fast programming cycles – things that would not have been possible before,” said Michael Wesley, lead author of the study and postdoc at MIT’s Computer Science and Artificial Intelligence Laboratory.
The study will be presented at the ACM conference on human factors in computing systems this month. Wessely’s co-authors include his advisor, Professor Stephanie Mueller, as well as postdoc Juhua Jin, recently graduated Catalia Nuengsigkapian ’19, MNG ’20, visiting student Alexei Kashapov, postdoc Isabel Kamar and Professor Dmitry Tsetserukol of the Science Institute.
ChromoUpdate is based on the researchers’ previous programmable material system called PhotoChromeleon. This method was “the first to show that we can have high-resolution multicolor textures that we can simply reprogram over and over again,” says Wesley. PhotoChromeleon uses a varnish-like ink containing cyan, magenta and yellow dyes. The user covered an object with a layer of ink, which can then be reprogrammed using light. First, the UV matrix was illuminated on the ink, completely saturating the dyes. The colorants were then selectively desaturated with a projector with visible light, bringing each pixel to the desired color and leaving behind the final image. PhotoChromeleon was innovative but slow. It took about 20 minutes to update the image. “We can speed up the process,” Weseley said.
They achieved this with ChromoUpdate, by fine-tuning the UV saturation process. Instead of using an LED that evenly blows up the entire surface, ChromoUpdate uses a UV projector that can vary light levels on the surface. Thus, the operator has pixel-level control over saturation levels. “We can saturate the material locally according to the exact model we want,” says Weseli. This saves time – someone who designs the exterior of the car may simply want to add racing stripes to an otherwise finished design. ChromoUpdate allows them to do just that without deleting and redesigning the entire exterior.
This selective saturation procedure allows designers to create a black-and-white design overview in seconds or a full-color prototype in minutes. This means that they could try out dozens of designs in one working session, a previously unattainable feat. “You can actually have a physical prototype to see if your design really works,” says Weseley. “You can see what it looks like when it’s exposed to sunlight or when shadows are cast. It’s not enough to just do it on a computer. “
This speed also means that ChromoUpdate can be used to provide real-time notifications without relying on screens. “One example is your coffee cup,” says Wesley. “You put your glass in our projector system and program it to show your daily schedule. And it updates directly when a new appointment comes for that day, or shows you the weather forecast. “
Wesley hopes to continue to improve the technology. Currently, light-activated ink specializes in smooth, hard surfaces such as cups, phone cases or car cases. But researchers are working on flexible, programmable textiles. “We’re looking at methods for dyeing fabrics and potentially using light-emitting fibers,” says Wesley. “So we could have clothes – T-shirts and shoes and all that stuff – that can be reprogrammed.”
The researchers partnered with a group of textile manufacturers in Paris to see how ChomoUpdate could be involved in the design process.
Reference: “ChromoUpdate: Quick iteration of photochromic color texture design using grayscale visualizations and local color updates” by Michael Wesley,, Yuhua Jin,, Cattalyya Nuengsigkapian,, Alexey Kashapov,, Isabel P. S. Kamar,, Dmitry Tsetseruku and Stephanie Mueller.
This study was funded in part by Ford.