Highly sensitive giant magnetoresistance (GMR) based ultra low differential pressure sensor

In this study, we demonstrate a simple, cost-effective, giant magnetoresistance (GMR) based magnetic pressure sensor. The basic principle lies behind the measurement of the change in the magnetic field profile generated by the deflected diaphragm attached with a permanent magnet. This magnetic field profile change on the sensor surface was measured by highly sensitive magnetoresistive gradiometer sensor. Based on studied magnetic field distribution of a magnet, a prototype pressure sensor was designed and fabricated, which consists of a polymer diaphragm, a permanent magnet and a giant magnetoresistance based magnetic field gradient sensor. The fabricated prototype was calibrated for ultra-low differential pressure range and it shows: (i) sensitivity up to 16.67 mu V/V/Pa and (ii) nonlinearity of 1.5% FS in the range of 0-300 Pa. The real time application was demonstrated where, the sensor was flush mounted on a NACA 4415 airfoil, and both the static and the dynamic suction pressures were recorded as a function of the wind velocity and also with different angle of attack (AOA). The measured pressure was found to be highly accurate while compared with existing static measurement system. (C) 2018 Elsevier B.V. All rights reserved.