Researchers have developed a technology that can be used to detect a body’s movements and vital information. The new soft transmission lines can be used in clothing or hospital bed sheets to make them capable of monitoring breathing and other vital movements, or in AI-powered textiles that allow robots to interact more safely and intuitively with humans.
The researchers invented a sensor that can detect different kinds of fabric deformation such as stretch, pressure, and torque all at the same time. Conventional sensors in textiles have had several drawbacks. First, they are fragile and break easily and second, a large number of them is required to cover a large area, which eliminates many of the advantages of fabrics. And third, each type of conventional sensor can detect only one kind of deformation.
By incorporating concepts from reflectometry, the team was able to create soft, fiber-shaped sensors that open up new doors for smart textiles. The technology works similar to a radar but sends out electrical pulses instead of electromagnetic waves. The fiber sensors operate like transmission lines for high-frequency communication. The system measures the time between when a signal is sent out and when it’s received and uses that to determine the exact location, type, and intensity of deformation.
This kind of detection technology has not been used in structures combining extended mechanical flexibility and high electronic performance, which are key for measuring deformations.
Creating the fibers is a complex task involving an optical fiber fabrication process applied to unusual materials such as elastomers or liquid metals that serve as the conductors. With these fibers, the entire surface of a fabric becomes one large sensor.