Using sound waves to create a smart T-shirt

Think about sporting a T-shirt that measures your respiration or gloves that translate your hand actions into instructions to your laptop. Researchers at ETH Zurich, led by Daniel Ahmed, Professor of Acoustic Robotics for Life Sciences and Healthcare, have laid the foundations for simply such sensible textiles.

In contrast to many earlier developments on this space, which often use electronics, the ETH researchers depend on acoustic waves handed by glass fibers. This makes the measurements extra exact and the textiles lighter, extra breathable and simpler to clean. “They’re additionally cheap as a result of we use available supplies, and the ability consumption could be very low,” says Ahmed.

Acoustic sensors embedded in cloth

The researchers name their growth SonoTextiles. They’ve remodeled regular materials into sensible sensors that react to the touch, stress and motion. “Whereas analysis has already been carried out into sensible textiles based mostly on acoustics, we’re the primary to discover using glass fiber together with alerts that use totally different frequencies,” explains Yingqiang Wang, the primary writer of the research that has been published in Nature Electronics.

The researchers have woven glass fibers into the material at common intervals. At one finish of every glass fiber is a small transmitter that emits sound waves. The opposite finish of every of the glass fibers is linked to a receiver that measures whether or not the waves have modified.

Every transmitter works at a distinct frequency. This implies it requires little computing energy to find out which fiber the sound waves have modified on. Earlier sensible textiles usually struggled with information overload and sign processing points, since every sensor location needed to be evaluated individually. “Sooner or later, the information may very well be despatched on to a pc or smartphone in actual time,” says Ahmed.

When a glass fiber strikes, the size of the acoustic waves passing by it modifications, as they lose vitality. Within the case of a T-shirt, this may be attributable to physique motion and even respiration. “We used frequencies within the ultrasonic vary, round 100 kilohertz—effectively past the vary of human listening to, which is between 20 hertz and 20 kilohertz,” Wang emphasizes.

Extremely versatile

The researchers have proven that their idea works within the lab. Sooner or later, SonoTextiles may very well be utilized in a wide range of methods: as a shirt or T-shirt, they may monitor the respiration of bronchial asthma sufferers and set off an alarm in an emergency.

In sports activities coaching and efficiency monitoring, athletes might obtain real-time evaluation of their actions, to optimize their efficiency and forestall accidents. The textiles even have the potential for signal language: gloves with this know-how might concurrently translate hand actions into textual content or speech. They may be utilized in digital or augmented actuality environments.

“SonoTextiles might even measure an individual’s posture and enhance their high quality of life as an assistive know-how,” provides Chaochao Solar, who shares first authorship of the research. Individuals who wish to enhance their posture might obtain focused suggestions to right poor posture. The textiles might additionally point out when a wheelchair consumer wants to alter place to forestall stress ulcers.

Though the on a regular basis usability of SonoTextiles is doubtlessly very excessive, Ahmed provides that there’s nonetheless room for enchancment by way of sensible software. Glass microfibers labored effectively as sound conductors within the lab, however they may doubtlessly break in on a regular basis use.

“The sweetness is that we will simply substitute the glass fibers with steel. Sound additionally propagates successfully by steel,” explains Ahmed. “We want to develop our analysis on this route and in addition into different functions.” The researchers now wish to make the system extra strong and look at how the electronics may be higher built-in into the textiles.