Monday, August 20, 2012

MEMS microphones

Traditionally a microphone is considered to be a relatively large electromechanic component that involves coils and bias currents. In the recent years the MEMS techniques have revolutionized also this area of sensors. The constant shrinking and lower power consumption of sensors makes us curious of the possible use cases those open.

One example of a small and energy efficient microphone is the Analog Devices ADMP404. Its dimensions are 3.35 mm × 2.50 mm × 0.88mm, which is rather small even for a MEMS microphone. The budgetary price listed by the manufacturer is $1.20@1kpcs, which should not be a deal breaker for most of the applications.

With a microphone the size of this it would be possible to make a very discrete microphone array for tracking audio sources in environments where visual methods to not work (darkness, heavy vegetation, haze, etc.). And because the ADMP404 consumes less than 250µA when active, these audio trackers could even be battery operated. This kind of mobile device would be perfect for spotting animals in a dense forest or when trying to locate where a gun shot originated.

If you have utilized MEMS microphones in your projects, feel free to share your experience in the comments. What microphone you decided to use and why?

More: datasheet, ADMP404

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