Introduction
The linear acceleration or directional movement of an object is measured by an accelerometer, whereas the angular velocity, tilt, or lateral orientation is measured by a Gyroscope Sensor. Accelerometers and gyroscopes are often used together because they complement one other.
In this blog, we will learn about Accelerometers and Gyroscopes, different types of Accelerometers and gyroscopes, and their applications.
Accelerometers
An accelerometer is an electrical sensor that detects and evaluates the acceleration forces acting on an item in order to establish its position in space and track its movement.
There are three types of accelerometers, each of which is designed to perform effectively in its particular setting. Piezoelectric, piezoresistance, and capacitive are the three types.
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Piezoelectric: A piezoelectric accelerometer detects changes in acceleration by using the piezoelectric effect (piezoelectric materials produce electricity when subjected to physical stress). The most typical applications for piezoelectric accelerometers are vibration and shock measurement.
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Piezoresistance: Piezoresistance accelerometers are less sensitive than piezoelectric accelerometers, making them more suitable for automotive crash testing. The resistance of a piezoresistance accelerometer rises in relation to the amount of force put on it.
- Capacitive: The acceleration of an item is determined by changes in electrical capacitance in capacitive accelerometers. The distance between the sensor's capacitor plates changes as the diaphragm moves when the sensor is accelerated.
MEMS Capacitive Accelerometer Diagram. (Source: HowToMechatronics)
Working of Accelerometers
An accelerometer is a device that uses an electromechanical sensor to measure static or dynamic acceleration.
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Static: The constant force acting on a body, such as gravity or friction, is known as static acceleration. To a significant extent, these pressures are predictable and uniform. For example, the gravitational acceleration is constant at 9.8m/s, and the gravitational force is about the same everywhere on the planet.
- Dynamic: Vibration or shock are two examples of non-uniform dynamic acceleration forces. An automobile accident is a great example of dynamic acceleration in action. When contrasted to its former state, the acceleration shift is sudden. Accelerometers, according to theory, can detect acceleration and convert it to observable values such as electrical signals.
Commonly Used Accelerometers
The most extensively used accelerometers for test and measurement purposes are piezoelectric (PE) accelerometers. These devices come in a variety of sensitivities, weights, sizes, and forms, and can measure frequencies ranging from a few Hz to 30 kHz.
Piezoelectric accelerometers come in two varieties (vibration sensors). The first is a "high impedance" output accelerometer, and the second is a "low impedance" output accelerometer.
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High Impedance: The piezoelectric crystal in this type of accelerometer generates an electrical charge that is directly coupled to the measurement devices. The charge output needs particular accommodations and instrumentation typically seen in research labs. This sort of accelerometer is also employed in high temperature (>120C) applications where low impedance variants aren't possible.
- Low Impedance: A low impedance output accelerometer is the second type of accelerometer. A charge accelerometer serves as the front end of a low impedance accelerometer, which has a minuscule built-in micro-circuit and FET transistor that transforms the charge into a low impedance voltage that can be easily interfaced with standard instruments. In industry, this sort of accelerometer is extensively utilized.
Applications of Accelerometers
Accelerometers are used in a variety of sectors. Some of them are:
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Digital Cameras and Smartphones: Accelerometers in smartphones and digital cameras rotate the display depending on how you hold it.
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Vehicles: The airbags are triggered by accelerometers, which provide a signal when they experience a violent shock.
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Drones: Accelerometers assist drones in maintaining their direction while flying.
- Rotating Machinery: Accelerometers are used in rotating machines to detect undulating vibrations.
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