Piezoresistive microcantilever-based gas sensor using dynamic mode measurement

The purpose of this paper is to investigate an application of a piezoresistive microcantilever for gas sensor using a dynamic mode operation. The working principle of the microcantilever sensor is based on the measurement of microcantilever deflection or resonance frequency change due to the objects attached on the microcantilever surface. The measurement was performed by using Wheatstone bridge circuit, which is constructed by two piezoresistors in the microcantilever and two external resistors, in order to measure the resonance frequency shift of the microcantilever vibration. The result shows that the voltage of oscillation peak-to-peak from the output of Wheatstone bridge circuit, which represents the microcantilever vibrations, decreases with the time due to the gas detection. This occurs due to the resonance frequency shift caused by the addition of gas molecules mass on the microcantilever surface. This result indicates that the developed system can be used as gas sensor.