Making Waves in Fashion

In the world of portable electronics, the smaller a device is, the better. Think back to the early days of mobile computing, for instance, when a computer was the size and weight of a tightly-packed suitcase. Sure, that is an upgrade compared to a desktop machine for getting work done on the go, but it is hardly convenient. Today’s smartphones are far better still, but even they have their limitations. As small as they are, they still are not especially good for applications like continuous health monitoring.

When sensors and computing units need to be in constant contact with the body, smaller and lighter systems are needed. This need has given rise to the concept of wearable devices, but even these are often too cumbersome to be practical. The ideal wearable device would simply be integrated into our clothing, rendering it completely transparent to us as it goes about its tasks.

We may not be fully there yet, but recent work coming out of ETH Zurich takes us a few steps closer. They have developed a lightweight and inexpensive shirt that can track the motions of the body — even subtle movements like breathing — using sound waves. The unique design of the shirt does not require any complex or bulky electronics for sensing, but instead makes use of thin glass microfibers.

Rather than relying on conventional electronic components for sensing, these so-called SonoTextiles use ultrasonic frequencies to detect motion, pressure, and touch. At the end of each of the glass microfibers, which are woven into the shirt in a grid, is a piezoelectric transducer that emits or receives sound waves that travel through the fibers. When the fiber is disturbed by motion, such as a breath or a bend of the arm, the properties of the sound waves change in a measurable way.

Because each glass fiber is tuned to a different frequency, the system avoids the heavy computational load often associated with sensor arrays. Instead of having to process a large number of raw signals from every sensor, it can isolate and analyze specific frequencies to identify exactly which fiber was disturbed. This design not only reduces energy consumption but also simplifies the software and hardware required to interpret the data.

Looking beyond the sensing components themselves, the textiles do still rely on piezoelectric transducers and some type of computing unit for readout and processing. As such, there is still some element of bulk and inconvenience associated with SonoTextiles. This would almost certainly complicate washing of the garments as well.

Even still, this smart fabric could be very useful. A shirt equipped with SonoTextiles could continuously monitor the breathing patterns of asthma patients, for instance, issuing alerts if abnormalities are detected. Or gloves made from the material could detect specific hand gestures, opening the door to real-time, transparent sign language translation.

With further development, SonoTextiles could fundamentally alter how we interact with our devices, turning everyday garments into active participants in our health, communication, and interactions with the environment.