A Capacitive Pressure Sensor With Adjustable Working Range for Deep Sea

Pressure sensors have widespread applications across various fields in air and underwater environments. However, the drastic pressure difference makes it hard for pressure sensors to measure air and deep-sea pressure under the same mechanism. In this study, we present a design of a capacitive pressure sensor based on the soft sensing membrane bending deformation to measure air pressure or extreme hydrostatic pressure. A mechanical model was developed to analyze the relationship between the membrane capacitance and the external pressure condition on different compressible mediums of the sensor. By changing the compressible mediums, the deformability of the sensor membrane under load can be modulated, enabling rapid adjustments to the working range of the sensor by at least four to five orders of magnitude. In the experiments, the sensor demonstrated the capability to monitor gas pressures of 1 kPa in air and hydrostatic pressures of 100 MPa (equal to hydrostatic pressure at a depth of 10000 m) in the pressure vessel. With consistent and stable performance across a low-to-high measurement range, this sensor proves versatile for applications such as wind pressure, depth, and environmental pressure measurements.