Everyone loves technology, whether it’s a cellphone, smartwatch, or other wearable device that we use to get through our daily lives. Unfortunately, one downside to these fancy gadgets is they become obsolete after a time and need to be upgraded. When this happens, we have no choice but to cast aside our old model for the latest and greatest one. But what if we could just upgrade the necessary parts instead of the entire item?
In a recent study published in Nature Electronics, engineers built a new artificial intelligence chip, with a view toward sustainable, modular electronics. The chip can be reconfigured, with layers that can be swapped out or stacked on, such as to add new sensors or updated processors.
The design comprises alternating layers of sensing and processing elements, along with light-emitting diodes (LED) that allow for the chip's layers to communicate optically. Other modular chip designs employ conventional wiring to relay signals between layers. Such intricate connections are difficult if not impossible to sever and rewire, making such stackable designs not reconfigurable.
"You can add as many computing layers and sensors as you want, such as for light, pressure, and even smell," says MIT postdoc Ji-hoon Kang, and co-author on the study. "We call this a LEGO-like reconfigurable AI chip because it has unlimited expandability depending on the combination of layers."
The team's design is currently configured to carry out basic image-recognition tasks. It does so via a layering of image sensors, LEDs, and processors made from artificial synapses -- arrays of memory resistors, or "memristors," that the team previously developed, which together function as a physical neural network, or "brain-on-a-chip." Each array can be trained to process and classify signals directly on a chip, without the need for external software or an Internet connection.
"Other chips are physically wired through metal, which makes them hard to rewire and redesign, so you'd need to make a new chip if you wanted to add any new function," says MIT postdoc Hyunseok Kim. "We replaced that physical wire connection with an optical communication system, which gives us the freedom to stack and add chips the way we want."
The team fabricated a single chip, with a computing core measuring about 4 square millimeters, or about the size of a piece of confetti. The chip is stacked with three image recognition "blocks," each comprising an image sensor, optical communication layer, and artificial synapse array for classifying one of three letters, M, I, or T. They then shone a pixellated image of random letters onto the chip and measured the electrical current that each neural network array produced in response. (The larger the current, the larger the chance that the image is indeed the letter that the particular array is trained to recognize.)
The team found that the chip correctly classified clear images of each letter, but it was less able to distinguish between blurry images, for instance between I and T. However, the researchers were able to quickly swap out the chip's processing layer for a better "denoising" processor, and found the chip then accurately identified the images.
The researchers plan to add more sensing and processing capabilities to the chip, and they envision the applications to be boundless.
As always keep doing science & keep looking up!
Sources: Nature Electronics
