The principles of MEMS technology are based upon the mechanical properties of the silicon -- stronger than steel but only a third of the weight -- to create moving structures. Combined with microelectronics, signals generated by the moving structures give perception and control capabilities to create a new generation of sensors.
Typically a MEMS accelerometer consists of interlocking fingers that are alternately moving and fixed. Acceleration is sensed by measuring the capacitance of the structure, which varies in proportion to changes in acceleration. The elements can be arranged like combs to make a linear accelerometer, as is the type used in airbags, or like the spokes of a wheel to make a rotational accelerometer.
While conventional microelectronics development focuses on incremental improvements of a well-established technology, MEMS challenge the way designers work, compelling them to think three dimensionally and to acquire a unique blend of multi-disciplinary skills combining electrical, semiconductor, and mechanical design.
Today MEMS devices are mainly used in the automotive market in airbags to detect very high-g levels, in the rollover detection systems, and in vehicle dynamic control systems to detect low-g levels.
As with any technology, certain market demands must to be attained prior to widespread adoption in a broad range of end applications. In the case of MEMS technology, low cost and higher sensitivities (new awareness of position and movements detected with higher accuracy) had to be achieved.
Today, communication, consumer and industrial markets are considered emerging markets for MEMS devices and will be the key drivers for their success. In a mobile phone or PDA, for example, these sensors can add a new, intuitive motion-based approach to navigation within and between pages. In addition, game pads can use these sensors to enable the user to play by just moving the pad to allow the sensor to determine the inclination rather than pushing buttons. Another application uses a MEMS based accelerometer as a vibration detector in home appliances., i.e. for washers or dryers.
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