Implementation, Characterization, and Evaluation of an Inexpensive Low-Power Low-Noise Infrasound Sensor Based on a Micromachined Differential Pressure Transducer and a Mechanical Filter

The implementation, characterization, and evaluation of a low-cost infrasound sensor developed at the Infrasound Laboratory at the New Mexico Institute of Mining and Technology (Infra-NMT) are described. This sensor is based on a commercial micromachined piezoresistive differential pressure transducer that uses a mechanical high-pass filter to reject low-frequency outband energy. The sensor features a low-noise, 2.02-mPa rms (0.5–2 Hz), 5.47-mPa rms (0.1–20 Hz), or 5.62-mPa rms (0.05–20 Hz), flat response between 0.01 and at least 40 Hz; inband sensitivity of 45.13 ± 0.23 μV Pa−1; and a nominal linear range from −124.5 to +124.5 Pa. Intended for outdoor applications, the influence of thermal changes in the sensor’s response has been minimized by using a thermal compensated pressure transducer powered by an ultralow drift (