Design of an acousto-magnetic oxygen sensor

The purpose of this study is to build an oxygen measurement system based on acousto-magnetic principle. Oxygen molecule can be attracted by a magnetic field due to its paramagnetic property. When oxygen molecules are driven by an alternative magnetic field, they vibrate and generate an acoustic signal. In consequence, the concentration of oxygen in the air can be measured by detecting the amplitude of acoustic pressure generated in the gap of a C-type electromagnet. Finite element analysis is also used to simulate the distribution of magnetic field intensity and force applied on oxygen molecules near the gap of electromagnet. The correlation coefficient of calibration using gases with known oxygen concentration is 0.9998 in the range from 0% to 100%. At the low concentration range, between 0% and 20%, the correlation coefficient is 0.9951.