This Wearable Pressure Sensor Is the Cat's Whiskers — or Inspired By Them, At Least

Researchers from Shinshu University and Nantong Univeristy have developed a novel form of pressure sensor, designed for use in sport-tracking wearables — and inspired by the whiskers of cats.

"Cats, known for their exception agility and sensory acuity, rely highly on their well-developed sensory systems for spatial awareness," explains Chunghong Zhu, associate professor at Shinshu University and corresponding author on the paper. "Their whiskers, or vibrissae, are robust yet highly sensitive tactile detectors, deeply embedded within special structures called follicle-sinus complexes (FSCs), which amplify and convert weak mechanical signals into neural stimuli, allowing cats to detect even the smallest pressure variations in their environment. Our biomass fiber aerogels mimic both cat vibrissae and FSCs, yielding excellent sensitivity and stability."

The team's sensor is based on hemp microfibers, an environmentally-friendly renewable resource which is used to create biomass fiber/sodium alginate aerogels (BFAs). These aerogels are extremely light and porous — and the fibers within mimic the operation of cat's whiskers, capturing and transmitting even weak mechanical disturbances with the cavity structure of the aerogel acting like the cat's sinus cavities to buffer and amplify the signals.

Prototype sensors built using the hemp-based BFAs proved able to detect pressure with a sensitivity of 6.01kPa⁻¹ and a response time of 255 milliseconds, while showing notable fatigue resistance and excellent dynamic response under varying rates of load. To demonstrate what that means in real-world terms, the researchers used the prototype in a wearable designed to capture carotid pulse signals, another which can recognize human motion patterns, and devices for handwriting recognition and Morse code information transmission — while a real-world test saw the sensor used in a wearable sports monitor designed to detect differences in badminton serving techniques.

"Our research offers a green, scalable solution for developing wearable pressure sensors," Zhu claims, "avoiding energy-intensive carbonization and or complex processing."

The team's work has been published in the journal Advanced Functional Materials under open-access terms.