Your New Shirt Can Hear Your Heartbeat!
A new fibre uncovered in MIT had gone off with a bang “This shows that the performance of the fibre on the membrane is comparable to a handheld microphone,” says Noel, one of the search crew.
Synthetics that can even be called a revolutionary fibre, function as a microphone, taking up sounds between a conversation while rustling bushes, and chirping birds and hence converting them to electrical signals. Studies state in Nature on March 16 that there is a substance that can be woven into a cloth which ultimately is able to hear handclaps and weak sounds, such as the wearer’s heartbeat. Fabrics like these could give a pleasant, or even attractive approach to monitor physiological processes or enhance hearing.
According to Wei Yan, a materials scientist at Nanyang Technological University in Singapore, acoustic fabrics have been around for hundreds of years but were only used to suppress sound. Yan, who worked on the fabric while at MIT, describes it as a “completely distinct concept.”
The human eardrum impressed Yan and his colleagues. The cochlea, which is a spiral-shaped bone found in the inner ear, in the process of auditory transduction converts sound waves into electrical signals by causing vibrations in the eardrum. “This eardrum turns out to be formed of fibres,” says Yoel Fink, an MIT materials expert. Collagen fibres radiate from the centre of the eardrum’s inner layers, while others create concentric rings. The crisscrossing filaments aid hearing and resemble the fabrics people weave, according to Fink.
Sound vibrates cloth at the nanoscale in a similar way to what happens in an eardrum. Cotton fibres and others from Twaron, a rigid polymer, easily transform incoming sound to vibrations in the new fabric. A single fibre containing a blend of piezoelectric materials, which produce a voltage when squeezed or bent, is woven together with these threads. The buckling and bending of the piezoelectric-containing fibre generate electrical impulses, which can be transferred via a tiny circuit board to a device that reads and records the voltage.
The team says that the fabric microphone is responsive to a wide range of noise levels, from a quiet library to noisy traffic, however, they are still investigating what signal processing is required to separate target sounds from ambient noise. This sound-sensing fabric, when integrated into clothing, feels like ordinary fabric, according to Yan, which also continues to work as a microphone after being washed ten times.
The researchers used the cloth to make a shirt that could hear the wearer’s heart like a stethoscope as a proof of concept. The fabric microphone might be used in this way to listen for murmurs and may one day be able to provide information equivalent to an echocardiogram, the ultrasound of the heart. Placing such microphones in clothing, if it proves to be useful as a monitoring and diagnostic tool, could make it easier for doctors to track cardiac problems in young children who have trouble staying still.
“It can be integrated with spacecraft skin to listen to (accumulating) space dust, or embedded into buildings to detect cracks or strains,” Yan proposes. “It can even be woven into a smart net to monitor fish in the ocean. The fibre is opening widespread opportunities.”
Works Cited
https://www.sciencenews.org/article/fabric-hear-heartbeat-fiber-vibration-voltage-sound-material
https://www.news18.com/news/buzz/this-fabric-can-hear-your-heartbeat-heres-how-4888352.html
