Micromachined Infrasound Sensors (Final Report)

The goals of this STTR were (i) to realize an infrasound sensor node that is low-cost, small, and therefore suitable for array deployment, while still achieving an input-referred noise floor lower than the low-noise model (LNM) across all frequencies of interest to the monitoring community, and (ii) to realize a complete digital-sensor system in which sensors have an on-board analog-to-digital converter (ADC) and integrated microcontroller, enabling two-way communication between sensors and data acquisition systems. This report summarizes the fabrication, testing, and packaging of a piezoresistive-sensed diaphragm designed specifically for infrasonic monitoring. Progress towards a digital sensor is also summarized. The design and realization of several digital subsystems is presented including data intake, digitization, timing, on-board storage, and transmission.