MEMS (micro-electromechanical system) or microsystems technology (MST) are made up of extremely small components ranging from 1 to 100 micrometers in size. It is a form of technology that is mostly used to define miniaturized mechanical and electro-mechanical elements that are made using the techniques of microfabrication. MEMS consist of micro-sensors and micro-actuators, which converts one form of energy to another. And micro-sensor converts measured mechanical to an electrical signal; whereas a micro-actuator does vice versa.
Components of MEMS
- Microelectronics and
- MEMS possess high sensitivity.
- MEMS devices have both mechanical and electrical components in micro-scale.
- MEMS minimizes the usage of energy and material which can help with reduction of costs.
- MEMS helps in improving accuracy, reproducibility, reliability, and sensitivity.
- In the initial setup, it requires a huge investment
- Designing part involves very complex procedures.
- Testing equipment’s of MEMS are costly.
MEMS accelerometer is a micro-electromechanical device which is used to measure acceleration and force. There are many types of accelerometer present in the market; they can be divided according to force that is to be measured. One of the most commonly used is the piezoelectric accelerometer. But they are bulky and cannot be used in every kind of operation, that is why small and highly functional device like MEMS accelerometer was developed.
These MEMS sensors have different applications such as gravity sensor, digital compass, GPS tracking, and smartphones for various controls like switch between landscape and portrait modes and to switch between the taps or pocket mode operations, used for anti-blur capture, gaming joysticks as step counters, used for stability of images in camcorders, 3D accelerometer is used in Nokia 5500 for tap gestures for example; you can change MP3’s by tapping on the phone when it is inside the pocket.
There are two types of MEMS accelerometers: variable capacitive and piezoresistive. Variable capacitives are highly sensitive and piezoresistive are low range devices used for acceleration measurement.
MEMS gyroscopes or MEMS angular rate sensors is a micro-electromechanical device which is small, with inexpensive sensors which are used to measure angular velocity or rotational motion or displacement. The unit of angular velocity is measured in revolutions per second (RPS) or degrees per second. It simply measures the speed of rotation.
Mechanically, Gyroscopes is spinning wheel or disc mounted on axle and the axle is free to assume directions.
They rely on the same principle that is vibrating objects undergoing rotation. Every MEMS gyroscopes have some form of the oscillating component from where acceleration can be detected. There are three types of Vibratory Gyroscopes: Vibrating Beam, Vibrating Disk, and Vibrating Shell.
MEMS gyroscopes are used for vehicle stability control and in image stabilization, airbag systems, Industrial robotics, Photography, automotive roll-over prevention, Car navigation systems and many other potential applications.
Pressure sensors is a piezoresistive pressure sensing die processed by MEMS technology. There are different types of applications for pressure sensors are available; a person has to select the right sensor from the wide variety of applications according to the use.
There are different types of pressure sensors which are classified according to their type of pressures such as high or low pressure and type of measurements.
MEMS pressure sensors plays an essential role in many fields of defense, medical, industrial, Beverage Machines, Washing Machines, aerospace applications, Industrial Machinery, automotive applications to monitor and measure the external pressure, the sensor is integrated into the tires of the vehicle, either internally or externally to measure and monitor the pressure of tires, it is also used as brake booster in vehicle braking system.
There are five types of pressure sensors:
- Absolute pressure sensor
- Vacuum pressure sensor
- Sealed pressure sensor
- Gauge pressure sensor
- Differential pressure sensor
MEMS magnetic field sensors are small-scale microelectromechanical systems which help in detecting and measuring magnetic fields. Sensors detect changes in force so that voltage frequency can be easily measured electronically. It can be placed close to the measurement location and thereby achieve higher spatial resolution.
It combines integrated bulk Hall cell technology and instrumentation circuitry to minimize temperature-related lot associated with silicon Hall cell characteristics.
MEMS magnetic field sensors are used for the linear angle, speed, rotational speed, linear position and position measurements in industrial, consumer applications, and automotive.
Over the years, researchers have discovered a huge number of microsensors for almost every modality like temperature, pressure, inertial forces, chemical species, magnetic fields, radiation, etc.
Performance of many of these micro machines have outranked that of macro-scale counterparts. The method of MEMS leverages benefits, such as low per-device production costs.
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