Microphones

Basic Description

Microphones are acoustic-to-electric transducers that convert sound in the form of acoustic pressure fluctuations into electrical signals. The most widely used microphones for automotive applications are condenser microphones due to their high accuracy and stability.

Condenser microphones consists of a highly stressed thin metal diaphragm (5 mm) and a backplate that acts as an electrode located very close to the metal diaphragm (15 to 30 mm). A variable capacitor is thus formed as the diaphragm moves in response to acoustic pressure variations.

In cars, microphones are used in communication systems, entertainment systems, glass breakage detectors, knock sensors, and noise cancelling systems. Sound detection is even being used to aid airbag systems by helping to determine the severeness of a crash [6].

Manufacturers

Andrea Electronics, B&K, Bosch, Gentex, Onosokki, Shure, ST Semiconductor

For More Information

[1] Microphone, Wikipedia.

[2] Engineering Acoustics/Microphone Design and Operation, Wikibooks, Oct. 2009.

[3] Types of Microphones, HowStuffWorks.com, Apr. 1, 2001.

[4] How Do Microphones Work?, Mediacollege.com.

[5] Airbags Learn to See and Hear, Continental website.

[6] Analog and Digital MEMS Microphone Design Considerations, Jared Lewis, EETimes, March 27, 2013.