Microelectromechanical systems (MEMS) are a class of devices characterised both by their small size and the manner in which these are made. These are made up of component sizes between 1 and 100 micrometres. MEMS devices can vary from simple structures to extremely complex electromechanical systems with multiple moving elements under the control of integrated microelectronics.
Generally, MEMS consist of mechanical microstructures, microactuators, microsensors and microelectronics in one package. Figure shows the block diagram of MEMS device.
Some common types of MEMS sensors available in the market are:
MEMS accelerometers
These sensors are used in smartphones for various controls including switching between landscape and portrait modes, anti-blur capture and pocket-mode operation. They are generally two types of MEMS accelerometers: variable capacitive and piezoresistive.
Variable capacitive (VC) MEMS accelerometers are the lower range, high sensitivity devices used for structural monitoring and constant acceleration measurements. Piezoresistive (PR) MEMS accelerometers are the higher range, low sensitivity devices used in shock and blast applications.
MEMS gyroscopes
These detect the angular displacement of an object. MEMS gyros are used for vehicle stability control.
MEMS gyroscopes are used in automotive roll-over prevention and airbag systems, image stabilization, and have many other potential applications [1].
MEMS pressure sensors
These sensors are used in automotive, industrial, medical, defence and aerospace applications. It also finds useful application in Washing Machines, Industrial Machinery, Beverage Machines, etc.
MEMS magnetic field sensors
A MEMS magnetic field sensor is a small-scale microelectromechanical system (MEMS) device for detecting and measuring magnetic fields (Magnetometer).Many of these operate by detecting effects of the Lorentz force: a change in voltage or resonant frequency may be measured electronically, or a mechanical displacement may be measured optically. These sensors find use in position sensing, current detection, speed detection, vehicle detection, space exploration, etc. Fluxgate sensors. These find many applications in space research, geophysics, mineral prospecting, automation and industrial process control.
