In a first, the digital fibre contains memory, temperature sensors, and a trained neural network program for inferring physical activity. 

MIT researchers have created the first fibre with digital capabilities, able to sense, store, analyse, and infer activity after being sewn into a shirt. 

Yoel Fink, who is a professor in the departments of materials science and engineering and electrical engineering and computer science, a Research Laboratory of Electronics principal investigator, and the senior author on the study, says digital fibres expand the possibilities for fabrics to uncover the context of hidden patterns in the human body that could be used for physical performance monitoring, medical inference, and early disease detection. 

MIT researchers have created the first fabric-fibre to have digital capabilities, ready to collect, store and analyse data using a neural network. Image: Anna Gitelson-Kahn. Photo: Roni Cnaani

Or, you might someday store your wedding music in the gown you wore on the big day – more on that later.

Fink and his colleagues described the features of the digital fibre in Nature Communications recently. Until now, electronic fibres have been analog – carrying a continuous electrical signal – rather than digital, where discrete bits of information can be encoded and processed in 0s and 1s.

“This work presents the first realisation of a fabric with the ability to store and process data digitally, adding a new information content dimension to textiles and allowing fabrics to be programmed literally,” says Fink.

Memory and more

The new fibre was created by placing hundreds of square silicon microscale digital chips into a preform that was then used to create a polymer fibre. By precisely controlling the polymer flow, the researchers were able to create a fibre with continuous electrical connection between the chips over a length of tens of metres.

The fibre itself is thin and flexible and can be passed through a needle, sewn into fabrics, and washed at least 10 times without breaking down. According to Loke. “When you put it into a shirt, you can’t feel it at all. You wouldn’t know it was there.” 

'This work presents the first realisation of a fabric with the ability to store and process data, adding a new information content dimension to textiles and allowing fabrics to be programmed literally', using a single process to connect hundreds of digital devices within a long flexible fibre, says Fink. Image: Anna Gitelson-Kahn. Photo: Roni Cnaani

Making a digital fibre "opens up different areas of opportunities and actually solves some of the problems of functional fibres", he says.

For instance, it offers a way to control individual elements within a fibre, from one point at the fibre’s end. “You can think of our fibre as a corridor, and the elements are like rooms, and they each have their own unique digital room numbers,” says Loke. The research team devised a digital addressing method that allows them to 'switch on' the functionality of one element without turning on all the elements.

A digital fibre can also store a lot of information in memory. The researchers were able to write, store, and read information on the fibre, including a 767-kilobit full-colour short film file and a 0.48 megabyte music file. The files can be stored for two months without power. 

A close-up photograph of the digital fibres on green fabric. Image: Anna Gitelson-Kahn. Photo: Roni Cnaani

When they were dreaming up “crazy ideas” for the fibre, says Loke, they thought about applications like a wedding gown that would store digital wedding music within the weave of its fabric, or even writing the story of the fibre’s creation into its components.

Fink notes that the research at MIT was in close collaboration with the textile department at RISD led by Missakian. Gitelson-Kahn incorporated the digital fibres into a knitted garment sleeve, thus paving the way to creating the first digital garment.

On-body artificial intelligence

The fibre also takes a few steps forward into artificial intelligence by including, within the fibre memory, a neural network of 1,650 connections. After sewing it around the armpit of a shirt, the researchers used the fibre to collect 270 minutes of surface body temperature data from a person wearing the shirt, and analyse how these data corresponded to different physical activities. Trained on these data, the fibre was able to determine with 96% accuracy what activity the person wearing it was engaged in.

Adding an AI component to the fibre further increases its possibilities, the researchers say. Fabrics with digital components can collect a lot of information across the body over time, and these “lush data” are perfect for machine learning algorithms, says Loke. 

A close-up photograph shows the fibre threading through a needle. Image: Pin-Wen Chou. Photo: Pin-Wen Chou

“This type of fabric could give quantity and quality open-source data for extracting out new body patterns that we did not know about before,” he says.

With this analytic power, the fibres someday could sense and alert people in real-time to health changes like a respiratory decline or an irregular heartbeat, or deliver muscle activation or heart rate data to athletes during training.

The fibre is controlled by a small external device, so the next step will be to design a new chip as a microcontroller that can be connected within the fibre itself.

“When we can do that, we can call it a fibre computer,” says Loke. 

In a first, the digital fibre contains memory, temperature sensors, and a trained neural network program for inferring physical activity.