MEMS - accelerometers

Bauman Moscow State Technical University

Faculty: Machine-building technologies

Essay

MEMS - accelerometers

Student of the group MT11-27: P.V.Ryabova

Teacher: T.D. Margaryan

Moscow, 2017 .

1.Introduction.

The subject of my research is MEMS accelerometers and gyroscopes. An accelerometer is an electromechanical device that will measure both static (gravity) and dynamic (vibration motion) accelerations. The development of accelerometers in technique has revolved, making MEMS accelerometer smaller, less powerful, easy to calibrate and use. MEMS-accelerometers costs low and have a wide range of applications. They can be found in cars, planes, mobile phones, and there are many other industrial applications. They became indispensable in automobile industry, computer and audio-video technology.

2.Howthe typical accelerometer works

In general, accelerometer acts as a damped mass on a spring. When the accelerometer experiences an acceleration, the mass is displaced to the point that the spring is able to accelerate the mass at the previous place. The displacement is measured to give the acceleration.

3.Types of accelerometers.

There are 3 basic types of measuments of proof-mass displacement in accelerometers: piezoelectric, piesoresistive and capacitive.

Piezoelectric devices use piesoceramics or quartz as a spring. Piesomatherial deformation convert the mechanical motion into an electric signal. Piesoresistive devices use a piesoresistors integrated in a spring to detect a spring deformation. This accelerometers are usually used for very high sensitive devices, because the process of production is very expensive, but the products are precise.

Another, the most common in technique is capacitive. This accelerometers use a magnetic source to generate the magnetic field between the proof-mass and a substrate. When the mass move to the next position, magnetic field between it and silicon substrate changes and this data is measured. Capacitive accelerometers are smaller than other, simply to produce and calibrate.

A typical MEMS capacitive accelerometer is composed of movable proof mass with a frame on the substrate. It has a lot of capacitor sets, all capacitors are wired parallel like a comb. In over to be more precise than a simple pair of capacitors.

4. Conclusion.

MEMS accelerometers are one of the simplest but also most applicable micro-electromechanical systems. Size of MEMS accelerometers is getting smaller, frequency response and sense range are getting wider. Prices of MEMS accelerometers and other MEMS devices aren’t excessive. I can be sure that the future for MEMS is bright. If you really want to get into the hardcore high level details of accelerometers, and want to try soldering surface mount packages, Analog Devices has a huge selection of accelerometers and datasheets.