A no-crosstalk multi-functional tactile sensor for precise physiological monitoring

Abstract

Tactile sensors with multifunctional sensing characteristics enhance people’s perception of external stimuli and have become an indispensable part of human–computer interaction. However, constructing a multi-functional tactile sensor that is able to respond to multiple stimuli without signal crosstalk still remains challenging. Here, we proposed a temperature–pressure integrated multi-functional tactile sensor (TP-MTS) by coupling thermoresistive and contact-electrification effects, which can simultaneously detect human body temperature and physiological motion. A sensing electrode model was validated by using a PVDF/PEG/Gr (polyvinylidene difluoride/Polyethylene terephthalate/graphene) composite thermoresistive film instead of the traditional metal as the electrode of the pressure sensing unit. The multi-functional tactile sensor converts temperature and pressure stimuli into two independent output signals from different paths, realizing simultaneous detection of temperature and pressure without signal crosstalk. The TP-MTS can achieve real-time temperature monitoring with a minimum resolution of 0.1℃ and a sensitivity of 1.51 % ℃^-1 and it could also detect pressure in a wide pressure range (0.25 kPa ∼ 253.87 kPa) with the sensitivity of 3.73 kPa⁻¹. Through the structure design and the huge impedance difference between the thermosensitive film and the triboelectric unit, the real-time monitoring of temperature and pulse is realized simultaneously in a single device without crosstalk.