Capacitive Pressure Sensor Based on Interdigitated Capacitor for Applications in Smart Textiles

Abstract

Today, Electronic skin (E-skin) is an active research area in human–computer interaction and intelligent wearable devices using different approaches. Our research aims to offer a systematic approach to electro-textile pressure sensors that rely on interdigitated capacitors (IDCs) for applications in artificial intelligence, particularly those involving smart wearable textile devices, including choosing appropriate materials to achieve high sensing performance. Firstly, the sensor characteristics were measured with a precision LCR meter throughout the frequency range from 1 to 300 kHz. The parallel plate measurement method is applied to measure and quantify the dielectric change as a function of pressure-sensing performance. The 16451B dielectric test fixture Keysight, which can measure the dielectric material with frequency, was applied to measure the dielectric constant and dissipation factor. The influence of choosing the substrate layer on sensitivity operation was included. Second, the influence of the volume percentage of CNTs on the characteristics of composite materials is examined. The presence of CNT improves the bonding strength of the sensor layer as well as the sensor's robustness when used in high-frequency applications. Thirdly, a large pressure detection range (up to 400 kPa) and quick response times (less than 20 ms) with a sensitivity range of 0.008125 (at 400 kPa) to 0.1 KPa1 have been made possible by the combination of CNTs with Ecoflex rubber (at 20 kPa). Finally, to obtain excellent performance, variables including frequency, fabric substrate, filler loading, and dielectric layer structure must be properly considered.