An ultra-low-power omnidirectional MEMS microphone array for wireless acoustic sensors

This paper presents an omnidirectional ultra low-power MEMS microphone array for use in low-power distributed wireless sensor networks. The microphone array is used for determining the Angle-of-Arrival (AoA) of sound events in an indoor environment. When the angles, measured by several wireless sensor nodes, are combined, a sound event can be located. This array consisting of 4 microphone elements, each with their own switchable two-stage amplifier, is completely configurable using an on board low-power microcontroller. This means that only the necessary elements are active when they are actually needed. Due to the selection of ultra low-power components and smart switching, the power consumption of the array is much lower than other similar designs, consuming only 0.8 mW when the array is activated and 66 nW during sleep.