Researchers Create a Fabric That Can ‘Hear’ Your Heartbeat

This fabric acts as both a speaker and microphone, detecting even faint noises and converting them into electrical signals

Red and blue fabrics
MIT researchers wove a fiber designed from a piezoelectric material with traditional yarn to create a machine-washable fabric.  Courtesy of the Finke Lab

Imagine sitting in your house, when suddenly you receive a phone call through your shirt. You answer the call and converse with the person on the other end.

Sound crazy? This scenario might soon be possible because of new research from engineers at the Massachusetts Institute of Technology and their collaborators at Rhode Island School of Design. These scientists have created a fabric that can hear sounds around you and inside your body. They published their research in the journal Nature

“Wearing an acoustic garment, you might talk through it to answer phone calls and communicate with others,” says lead author Wei Yan, who is now a professor at the Nanyang Technological University in Singapore, in an MIT statement. “In addition, this fabric can imperceptibly interface with the human skin, enabling wearers to monitor their heart and respiratory condition in a comfortable, continuous, real-time and long-term manner.”

To create the garment, the team wove a flexible piezoelectric fiber into fabric. Piezoelectric materials “generate internal electrical charge from applied mechanical stress,” per Sciencing’s Francine Mends. When the fiber is exposed to sound waves, vibrations create electrical signals—similar to how our ears work. 

Piezoelectric materials have “huge potential” for a variety of applications, Vijay Thakur, a materials scientist at Scotland’s Rural College in Edinburgh who was not involved in the research, tells Science NewsCarolyn Wilke, including monitoring human bodies and aircraft materials. 

The team wove the fibers in with traditional yarns to create panels, which they then sewed into a shirt. To test the shirt’s ability to detect the direction of a sound, researchers clapped at various angles away from the garment. 

The front and back view of a button-down shirt. The back shows two sewn-in panels
Researchers sewed in two panels of acoustic fabric in the back of a dress shirt. Courtesy of the Finke Lab

“The fabric was able to detect the angle of the sound to within 1 degree at a distance of 3 meters away,” says co-author and MIT researcher Grace Noel in the statement.

They also tested whether clothes could act as a fabric stethoscope by sewing a single fiber into the inner lining of a shirt, according to MIT. Yoel Fink, a co-author and materials scientist at MIT, says in the statement that this could be used in maternity clothes in the future to monitor a baby’s fetal heartbeat. The fabric can even be machine-washed. 

“The resulting fabrics are capable of efficiently detecting audible sounds with performance on par with commercial microphones,” the authors write in the paper. The fibers can pick up noises such as human speech, birds chirping and leaves rustling, per the study. 

The fibers can also amplify sounds, which could help those who are hard of hearing. This solution could also be used to help detect cracks in buildings or be woven into a net to monitor fish, the researchers say in the statement.

Ultimately, Fink tells Popular Science’s Shi En Kim that his goal is to put other digital operations within fabric, including information storage and signal processing. 

“Computers are going to really become fabrics,” he tells the publication. “We’re getting very close.”