When Nikola Tesla provided If we had portable phones that could display videos, photos and more, his reflections seemed like a distant dream. Almost 100 years later, smartphones are like an extra appendage for many of us.
Digital manufacturing engineers are now working to expand the visualization capabilities of other everyday objects. One avenue they are exploring is reprogrammable surfaces (or elements whose appearance we can digitally alter) to help users present important information, such as health statistics, as well as new designs on things like a wall, a mug or a shoe.
Researchers at MIT's Computer Science and artificial intelligence Laboratory (CSAIL), the University of California at Berkeley, and Aarhus University have taken an intriguing step forward by manufacturing “Chrome Holder”, a portable lighting system and design tool that can change the color and textures of various objects. Equipped with ultraviolet (UV) and red, green and blue (RGB) LEDs, the device can be attached to everyday objects such as shirts and headphones. Once a user creates a design and sends it to a PortaChrome machine via Bluetooth, the surface can be programmed into multi-color displays of health data, entertainment and fashion designs.
For an item to be reprogrammable, the object must be coated with photochromic dye, an invisible ink that can be turned into different colors with light patterns. Once coated, people can create and transmit patterns to the item through the team's graphic design software, or use the team's API to interact directly with the device and incorporate data-driven designs. When attached to a surface, PortaChrome's UV lights saturate the tint while the RGB LEDs desaturate it, activating the colors and ensuring each pixel has the hue that matches the desired design.
Zhu and his colleagues' integrated light system changes colors of objects in less than four minutes on average, eight times faster than their previous work, “Photo-Chromeleon.” This increase in speed comes from switching to a light source that makes contact with the object to transmit UV and RGB rays. Photo-Chromeleon used a projector to help activate the color-changing properties of photochromic dye, where the light on the surface of the object has a reduced intensity.
“PortaChrome provides a more convenient way to reprogram your environment,” says Yunyi Zhu '20, MEng '21, an MIT doctoral student in electrical and computer engineering, a CSAIL affiliate, and lead author of a document about work. “Compared to our previous projector-based system, PortaChrome is a more portable light source that can be placed directly on the photochromic surface. This allows the color change to occur without user intervention and helps us avoid contaminating our environment with UV rays. As a result, users can wear their heart rate chart on their t-shirt after exercising, for example.”
Renew everyday objects
In demonstrations, PortaChrome displayed health data on different surfaces. One user walked with PortaChrome sewn to his backpack, putting it in direct contact with the back of his shirt, which was coated with photochromic dye. The altitude and heart rate sensors sent data to the lighting device, which was then converted into a graph using a reprogramming script developed by the researchers. This process created a health visualization on the back of the wearer's shirt. In a similar sample, MIT researchers showed a gradually gathering heart on the back of a tablet to show how a user progressed toward a fitness goal.
PortaChrome also showed a talent for customizing wearable devices. For example, the researchers redesigned a white headset with blue lines on the sides and yellow and purple horizontal stripes. The headphones were coated with photochromic dye, and then the team placed the PortaChrome device inside the headphone case. Eventually, the researchers successfully reprogrammed their patterns into the object, which looked like a watercolor. The researchers also changed the color of a wrist splint to match different clothing using this process.
Eventually, the work could be used to digitize consumers' belongings. Imagine putting on a cape that can change the entire design of your shirt or using your car cover to give your vehicle a new look.
Main ingredients of PortaChrome
Hardware-wise, PortaChrome is a combination of four main ingredients. Your wearable device consists of a textile base as a backbone, a textile layer with the UV lights welded on and another with the RGB lights glued on, and a silicone diffusion layer to top it off. Resembling a translucent honeycomb, the silicone layer covers intertwined UV and RGB LEDs and directs them toward individual pixels to properly illuminate a design on a surface.
This device can be flexibly wrapped around objects with different shapes. For tables and other flat surfaces, you can place PortaChrome on top, like a placemat. For a curved item like a thermos, you can wrap the light source like a coffee mug sleeve to ensure it reprograms the entire surface.
The portable, flexible light system is designed with tools available in the maker space (like laser cutters, for example), and the same method can be replicated with flexible PCB materials and other mass manufacturing systems.
While it can also quickly turn our surroundings into dynamic displays, Zhu and his colleagues believe it could benefit from further increases in speed. They would like to use smaller LEDs, with the likely result of a surface that could be reprogrammed in seconds with a higher resolution design, thanks to higher light intensity.
“The surfaces of our everyday things are encoded with visual colors and textures, providing crucial information and shaping how we interact with them,” says Georgia tech postdoc Tingyu Cheng, who was not involved in the research. “PortaChrome is taking a step forward by providing reprogrammable surfaces with the integration of flexible light sources (UV and RGB LEDs) and photochromic pigments into everyday objects, pixelating the environment with dynamic colors and patterns. The capabilities demonstrated by PortaChrome could revolutionize the way we interact with our environment, particularly in domains such as personalized fashion and adaptive user interfaces. “This technology enables real-time personalization that integrates seamlessly into daily life, offering a glimpse into the future of ‘ubiquitous displays.’”
Zhu is joined by nine CSAIL affiliates in the article: MIT PhD student and MIT Media Lab affiliate Cedric Honnet; former visiting university researchers Yixiao Kang, Angelina J. Zheng and Grace Tang; MIT undergraduate Luca Musk; University of Michigan Assistant Professor Junyi Zhu SM '19, PhD '24; Michael Wessely, recent postdoc and assistant professor at Aarhus University; and senior author Stefanie Mueller, a TIBCO career development associate professor in the departments of Electrical Engineering, Computer Science, and Mechanical Engineering at MIT and leader of the HCI Engineering Group at CSAIL.
This work was supported by the MIT-GIST Joint Research Program and was presented at the ACM Symposium on User Interface Software and technology in October.
