Unlike some previous developments in this field, the ETH researchers pass acoustic waves through glass fibres, thereby making measurements more precise and the textiles lighter, more breathable and easier to wash.
“While research has already been conducted into smart textiles based on acoustics, we are the first to explore the use of glass fibre in combination with signals that use different frequencies,” said Yingqiang Wang, the first author of the study that has been published in Nature Electronics.
The researchers have woven glass fibres into the fabric at regular intervals. At one end of each glass fibre is a small transmitter that emits sound waves. The other end of each of the glass fibres is connected to a receiver that measures whether the waves have changed.
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Each transmitter works at a different frequency, so it requires little computing power to determine which fibre the sound waves have changed on. According to ETH Zurich, previous smart textiles often struggled with data overload and signal processing issues since each sensor location had to be evaluated individually.
“In the future, the data could be sent directly to a computer or smartphone in real time,” said Daniel Ahmed, Professor of Acoustic Robotics for Life Sciences and Healthcare at ETH.
When a glass fibre moves, the length of the acoustic waves passing through it changes, as they lose energy. In the case of a T-shirt, this can be caused by body movement or breathing.
“We used frequencies in the ultrasonic range, around 100 kHz – well beyond the range of human hearing, which is between 20Hz and 20kHz,” said Wang.
The researchers have shown that their concept works in the lab. In the future, SonoTextiles could be used in a variety of ways: as a shirt or T-shirt, they could monitor the breathing of asthma patients and trigger an alarm in an emergency.
In sports training and performance monitoring, athletes could receive real-time analysis of their movements to optimise their performance and prevent injuries. The textiles also have potential for sign language as gloves with this technology could simultaneously translate hand movements into text or speech. They could also be used in virtual or augmented reality environments.
The researchers now want to make the system more robust and examine how the electronics can be better integrated into the textiles.
Comment: The UK is closer to deindustrialisation than reindustrialisation
"..have been years in the making" and are embedded in the actors - thus making it difficult for UK industry to move on and develop and apply...