A low-power MEMS microphone array for wireless acoustic sensors

In this article we present the design of a low-power MEMS microphone array for wireless sensors. The array is used as part of a device that performs acoustic Angle-Of-Arrival (AOA) measurements. The power consumption of this design is lower than that of comparable designs. Each of the 4 analog channels (each with a microphone and amplifier) can be turned on or off (standby) separately. The power consumption is 1.8 mW per channel, and about 0.13 μW in standby. For a single AOA detection cycle (array activation, audio sampling, AOA computation), the energy consumption is 6.02 mJ. When consecutive AOA detections are performed, the energy cost per detection converges to 3.20 mJ. The AOA accuracy corresponds with the expectations. With a mean error of 4°, this is lower than that of comparable designs.