Engineers at MIT have developed a modular computer chip with components that can communicate using flashes of light. This could allow for electronics that can easily be upgraded with new sensors or processors, rather than replacing the whole chip.

The electronics market has gotten to a point where many consumers will turn over a smartphone every year for a newer, shinier, slightly better model. Upgrading individual parts isn’t really an option for many devices, requiring the whole thing to be replaced. That’s not the most environmentally responsible attitude to electronics.

Modularity could go a long way, allowing users to swap in new or improved functionality, like bigger batteries or upgraded cameras. So for the new study, the MIT team has now demonstrated this approach within a single computer chip.

The team’s modular chip is made up of layered components like artificial intelligence, processors and sensors, which can be stacked or swapped in to build a chip to perform specific functions as needed, or upgrade it as new technology becomes available.

“You can add as many computing layers and sensors as you want, such as for light, pressure, and even smell,” says Jihoon Kang, an author of the study. “We call this a LEGO-like reconfigurable AI chip because it has unlimited expandability depending on the combination of layers.”

But perhaps the most impressive thing is how the layers of this chip interact with each other. Modular electronics face a problem in getting new and old components to communicate with each other in a fast and simple way. The MIT chip, however, uses flashes of light to convey information between each layer.

The team fitted each layered component of the chip with LEDs and photodetectors that line up with those of the next component. When one part needs to communicate with another, it flashes its LED pixels in a certain pattern that encodes the data, which the photodetectors of the receiving layer can interpret.

To demonstrate this design, the team created a chip measuring 4 mm2, made up of three computing layers. Each layer contained an image sensor, an optical communications system, and an artificial synapse array which was designed to recognize a specific letter – M, I or T.

To test it out, the researchers exposed the chip to pixelated images of random letters, then measured the strength of the electrical current that each array produced in response. The stronger the current, the better the array recognizes the letter.

Using this process, the team found that the chip was able to classify images of letters it was trained on very well if the images were clear, but less so when blurry. To demonstrate the modularity of the chip, the engineers then slotted in a “denoising” processor that could handle the blurry images better, and sure enough the chip’s letter recognition improved.

“We showed stackability, replaceability, and the ability to insert a new function into the chip,” said Min-Kyu Song, an author of the study.

The team plans to apply the technique to “edge computing devices,” which are small, specialized sensors for the Internet of Things.

The research was published in the journal Nature Electronics.

Source: MIT