Low-Power Ultrasonic Dosimeter

The Interdisciplinary Consulting Corporation (IC2) proposes to develop a low-power, wearable ultrasonic dosimeter including an instrumentation-grade, ultrasonic microphone using microelectromechanical systems (MEMS) piezoelectric sensing, advanced packaging technology, and low-power analog and digital electronics. The goal of this research is to develop microphones and low-power electronics that will enable continuous monitoring of ultrasonic energy in the wearerÆs environment and recording of events that could be harmful to the wearer, while leveraging MEMS batch-fabrication technology to reduce the sensor size and low-power electronics to provide a rechargeable, wearable package. This device will address the limitations and challenges associated with measurement and quantification of ultrasonic radiation exposure in workplace and home environments. The proposed innovation is to combine MEMS sensor technology with advanced packaging technology, and low-power analog and digital electronics to develop a low-power, wearable ultrasonic dosimeter. Leveraging past experience with piezoelectric microphones and low-power, wireless data acquisition systems, the proposed effort focuses on optimizing the sensor design for ultrasonic frequencies of interest, co-locating the low-power signal conditioning, analog-to-digital conversion, and data recording electronics with the sensor, and designing a small form-factor, rechargeable, minimally intrusive enclosure that is wearable by an end user. The instrumentation-grade microphones are batch fabricated using micromachining technologies to enable low cost per device and consistent device performance.Ā The piezoelectric sensors consist of a cavity-vent structure with an annular piezoelectric ring situated on the edge of the diaphragm. Using flip-chip bonding and advanced packaging techniques, the sensors are mounted into a small enclosure along with low-power signal conditioning, analog-to-digital conversion, and data recording electronics to create a wearable device.Ā The proposed ultrasonic piezoelectric MEMS microphones offer multiple advantages over competing technologies including lower power consumption and significantly lower cost per channel while meeting strict performance requirements. The low-power analog and digital electronics will enable continuous monitoring, detection, and recording of ultrasonic events and will be powered by a small rechargeable battery. These advantages combine to reduce the size and cost of ultrasonic sound level measurement equipment, enabling the creation of a wearable ultrasonic dosimeter for use in industrial settings. Ā