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MEMS stands for Micro-Electro Mechanical System. It is the technology which is based advanced technologies used to form small structures with dimensions in micrometer scale. MEMS technology is now being employed to manufacture state-of-the-art MEMS-based accelerometers.
Initially, MEMS accelerometers was designed using piezoresistors. Since piezoresistors are less sensitive than capacitive detection, the majority of MEMS accelerometers nowadays use capacitive sensing principle. MEMS-based accelerometer typically consists of a proof mass with plates attached through a mechanical suspension system to a reference frame. Movable plates (part of the seismic mass) and the outer plates in stationary state form differential capacitor. Because of the forces due to acceleration, the seismic mass deflects; the deflection is measured in terms of capacitance change. [4,3.]
Figure 10. MEMS-based accelerometer structure [4,3]
Materials and manufacturing technologies
Find more information what materials have been used in your sensor and how the sensor is manufactured. You could use the following questions as a starting point:
- Does it contain Silicon? Is the structure crystalline or polysilicon?
- What plastic materials are used and why?
- Are metals used? Which ones? Why?
- How about ceramics and glasses?
- Why some materials are more favorable than others in your sensor or application?
- How is the sensor manufactured?
- What are the typical manufacturing process steps?
Complement your sensor article with these information. Add a sub-chapter to your article and named it: Materials and manufacturing technologies.
Selection of an accelerometer
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Accelerometers have many different applications ranging from industry, entertainment, sports to education. These applications can be, for example, triggering airbag deployments or monitoring of nuclear reactors. Accelerometers can also be used to measure static acceleration (gravity), tilt of an object, dynamic acceleration in an aircraft, shock to an object in a car, orientation or vibration of an object. Cell phones, washing machines or computers nowadays also have accelerometers.
Material and manufacturing process
under construction...
References
- Johnson C. Process Control: Instrumentation Technology. Prentice Hall; 2006.
- Kushwah R. Accelerometer [online]. Kushwah; 16 April 2012.
URL: http://ei-notes.blogspot.fi/2012/04/accelerometer.html. Accessed 1 April 2014. - Jain P. Accelerometers [online]. EngineersGarage.
URL: http://www.engineersgarage.com/articles/accelerometer. Accessed 1 April 2014. - Micro Device Laboratory. Result [online].
URL: http://mdl.pme.nthu.edu.tw/nthu_pme_lab_eng/pages/result/16.html. Accessed 1 April 2014. - rdes27. Sensors [online].
URL: http://sensors-actuators-info.blogspot.fi/. Accessed 1 April 2014 - Fraden J. Handbook of Modern Sensors: Physics, Designs, and Applications (4th edition)
STMicroelectronics. LIS3L02AL MEMS inertial sensor datasheet [online]. STMicroelectronics; May 2006.
URL: http://www.e-brt.com/upload/files/20111011111758_77.pdf. Accessed 9 April 2014.Analog Devices. ACCELEROMETER SPECIFICATIONS - QUICK DEFINITIONS [online]. Analog Devices.
URL: http://www.analog.com/en/content/td_accelerometer_specifications_definitions/fca.html. Accessed 9 April 2014.- Analog Devices. Tilt Measurement Using a Dual Axis Accelerometer [online]. Analog Devices.
URL: http://www.analog.com/en/circuits-from-the-lab/cn0189/vc.html. Accessed 20 April 2014. Analog Devices. Circuit Note CN-0189 - Tilt Measurement Using a Dual Axis Accelerometer [online]. Analog Devices; 2012.
URL: http://www.analog.com/static/imported-files/circuit_notes/CN0189.pdf. Accessed 20 April 2014.Analog Devices. Precision +-1.7g, +-5g, +-18g Single-/Dual-Axis iMEMS Accelerometer ADXL103/ADXL203 Data Sheet [online]. Analog Devices.
URL: http://www.analog.com/static/imported-files/data_sheets/ADXL103_203.pdf. Accessed 20 April 2014.