Chroma Chameleon

In the future, the phrase “changing your shirt” may take on a whole new meaning. A group led by researchers at MIT CSAIL has developed a new technology that makes it possible to literally change a shirt — or just about any other surface — such that it has a different color or texture in just a few minutes. The new look of the surface is fully programmable and is enough to make a chameleon jealous.

Typically, color changing tricks of this sort are done by some type of projection system. This works quite well if the target item is stationary and nothing comes between it and the projectors. But this is the real world, and those conditions are unrealistic in many cases. Articles of clothing and wearable electronic devices, in particular, must be portable, rendering projection-based techniques completely impractical.

Members of this team previously developed a system called PhotoChromeleon that makes these projected patterns permanent. That was a big step forward, but even still complex equipment was required and it took upwards of an hour to program a new pattern.

The team’s latest solution, called PortaChrome, makes the appearance of items like shirts or headphones programmable by first coating them with a photochromic dye. This dye is saturated by ultraviolet light, causing it to turn black. Visible light, on the other hand, desaturates the dye. By shining visible light of a specified color on the dye, it will change to that same color.

Once an object has been dyed, the PortaChrome hardware is used to program it. It consists of a flexible, textile base that has a grid of ultraviolet and RGB LEDs on its surface. A silicone layer sits on top of the LEDs to diffuse the light and direct the light of each LED in a specific direction, such that it can serve as a pixel. The flexible design of PortaChrome makes it suitable for use with even very irregularly shaped objects.

An application was developed to assist users in creating patterns for PortaChrome to display. By using this — in conjunction with the hardware and a dyed surface — the researchers demonstrated how their technology can be integrated into wearables like backpacks, headphones, and shirts, where health data, such as one's heart rate, was displayed.

The tools and components required to build a PortaChrome system are widely available, making this system accessible even to hobbyists tinkering at home. The team noted that PortaChrome can also be adapted for mass production, however, which means it could eventually be incorporated into an off-the-shelf consumer product.

While PortaChrome is much more practical than techniques of the past, the need for external hardware to program the surface, and a wait time of a few minutes, still render it impractical for displaying frequently updated information. But for someone that just wants to change their clothing or electronic devices to match how they are feeling on any given day, PortaChrome looks like it could be a lot of fun to play with. Perhaps with some updates this tool will eventually be more practical for making quick updates, or even displaying real-time information.