A Flexible Crosstalk-Free Piezoresistive Pressure Sensor Array Based on Interdigital-Electrode for High-Precision Pressure Mapping

Flexible piezoresistive pressure sensor arrays have become an attractive field of research due to their extensive use in human-machine interface, human posture monitoring, healthcare, and other scenarios. However, the inherent crosstalk issue always affects the sensing performance of piezoresistive sensor arrays. In this study, a flexible crosstalk-free pressure sensor array with an interdigital-electrode layout structure is demonstrated. The device mainly consists of an interdigital-electrode (IDE) array on a flexible printed circuit (FPC) board, pressure-sensitive Velostat films, and current-regulating diodes. The combination of IDE and diodes allows a simplified sensor structure with an excellent ability to pattern crosstalk-free pres-sure distributions. The performance of a single sensing unit has been fully characterized, and a high spatial resolution pressure sensor array of $9\times 14$ sensing units is successfully fabricated and tested. As examples of pressure mapping, the proposed sensor array has been used to measure the pressure distribution of foot stepping, palm pressing, and sitting with high precision.