High sensitivity knitted fabric bi-directional pressure sensor based on conductive blended yarn

Flexible pressure sensors have a broad range of applications, such as physiological signal monitoring, human-machine interfacing devices and soft robotics. The main challenges are laborious fabrication process, complex structure, poor conforming to human body. In this study, we report a wearable pressure sensor based on conductive blended yarn that is made into a plain knit fabric construction. The knitted fabric can be used as both wale direction sensor and course direction sensor with different sensitivities. The underlying sensing mechanisms for the two directions are analyzed using equivalent circuit networks. The pressure sensor demonstrates high sensitivity (0.73 kPa⁻¹) for a wide range of pressure from nearly zero to 100 kPa and a very short response time (less than 0.4 s). (paper)