Fabric-based sensor for applications in biomechanical pressure measurement

Abstract

Wearable pressure sensor is an important element in human gait and biomechanical investigations. Many studies have been carried out to ensure its reliability and comfort to the user even when the sensor has to be operated under extreme conditions such as uneven surface with high curvature area, high humidity environment, and wide range of dynamic pressure. However, the existing pressure sensors that could endure such extreme conditions usually involve complex fabrication processes and often incur high cost of materials. Therefore, in this paper we present a novel pressure sensor made of low cost fabric materials with simple fabrication process. The sensor is constructed from a conductive fabric using piezoresistive technique. A unit area of our pressure sensor is made of a thin layer of piezoresistive material and it is placed in between two layers of conductive fabrics. To vary sensing sensitivity and to cater wide range of pressure, our proposed sensor uses special mesh layers which are placed in between the piezoresistive layer and the conductive layers. This way, wide range of dynamic pressure can be captured. To test the proposed sensor, five units of pressure sensors have been designed with variety of mesh layering techniques. These sensors are tested using 0- 3 kg load and the data are analyzed graphically. Our experimental results on the resistive versus pressure response show a similar trend as compared with the existing popular pressure sensor such as flexiforce in term of force versus resistance curve. The use of mesh layer allows measurement of higher magnitude of pressure. Since the performance of our sensor can be tailored to exhibits the performance of the exiting commercial sensors therefore the proposed technique can be an alternative affordable solution to that of the existing expensive sensors.