Modular QMB sensors array for E-health applications

This work describes the design and development of a gas sensor module, using QMBs (Quartz Crystal Microbalances) as sensing element, for E-health applications (e.g. Exhaled Breath Analysis). The developed module can be used with other modules, as an array of gas sensors, in a master-slave architecture based on an I2C communication bus. A custom electronic interface has been developed to properly drive the QMBs and a microcontroller has been used to read the output signal: the module is able to use QMBs with a fundamental resonant frequency ranging from 20 to 50 MHz, with a sensing resolution of about 1 Hz. The performances of the sensing modules have been investigated with a particular focus on sensor's responses to typical Relative Humidity and Temperature levels of exhaled breath samples.