Accelerometer

Introduction

An accelerometer is a tool used to measure the acceleration of a body. We are able to monitor and analyse both linear and angular acceleration using the accelerometer’s sensor. This function is used by us in many aspects of daily life and is a requirement for many fundamental systems and gadgets. An accelerometer, which measures numbers in one, two, or three planes, can be used to measure the acceleration force, or “g.” When the threshold is reached, a routine may start. Capacitive accelerometers, piezoelectric accelerometers, and piezoresistance accelerometers are the three basic types of accelerometers. Both inertial navigation and guidance systems make extensive use of them.

What is an Accelerometer?

An accelerometer is a sensor that allows us to track both linear and angular acceleration. This function is used by us in many aspects of daily life and is a requirement for many fundamental systems and gadgets. Static forces and dynamic forces are the two categories into which acceleration forces are divided. Static forces are those that can be constantly applied to an object, such as friction or gravity. Dynamic forces are those that can be described as “moving” and are applied to the object at various rates (for instance, vibration).

How does an Accelerometer work?

• The accelerometer operates on a very straightforward principle. An accelerometer, which measures numbers in one, two, or three planes, can be used to measure the acceleration force, or “g.”
• If the threshold is exceeded, it can trigger a routine. 
• The three-axis accelerometer, which features a system made up of three different accelerometers, is the most often used type of accelerometer. Each one calculates the acceleration in the X, Y, and Z planes in a separate direction.
• One of the popular models of a 3 axis accelerometer is the OKYSTAR OKY3230 type. The accelerometer will only estimate the force of gravity as the standard when it is in a stable position, which is when there is no external acceleration experienced by the accelerometer.
• Now, if we take a look at a three axes accelerometer and put it in a position where the sensor on the X axis points in the left direction, the Y axis points down, and the Z axis points forward, then the accelerometer will present the reading that is as follows:

$X=0 g, Y=1 g, Z=0 g$

Purpose of accelerometer

An accelerometer is a device used in vehicles to measure the acceleration motion brought on by either motion or gravity. The accelerometer’s primary function is to transform mechanical motion into electrical impulses.

Capacitive accelerometer

A capacitive accelerometer measures an object’s acceleration by monitoring changes in electrical capacitance. The most popular accelerometer is this one.

• Comparing the capacitive accelerometers to the other two types of accelerometers, they are the smallest and least expensive.
• Its name implies that it is a micro-electro mechanical system, and its parts range in size from 1 to 100 micrometres.
• The primary mechanism by which the capacitive accelerometer operates relies on the movement of a known mass suspended on springs. The mass is attached to one end of the spring, and the capacitor is attached to the other.
• When the sensor is subjected to a force, the mass moves, changing the capacitance of the capacitors and, in turn, the distance between their plates.
• However, for a variety of high amplitude signals and frequencies, this accelerometer’s accuracy is lower than that of other types of accelerometers.

Piezoelectric accelerometer

Using the piezoelectric effect, piezoelectric accelerometers can identify changes in acceleration.

• The working principle is similar to the piezoresistive one.
• When a material, often PZT, is subjected to acceleration, a deformation occurs that results in a change. But in this instance, it’s electric charge rather than resistance.
• Piezoelectric accelerometers have a very high sensitivity and accuracy, making them suitable for widespread application.
• They can be used for crash and impact tests in challenging conditions as well as for obtaining particularly sophisticated and accurate seismic estimation.

Piezoresistance accelerometers

As the pressure exerted on the piezoresistance accelerators increases, so does their resistance.

• As compared to piezoelectric accelerometers, these are far less sensitive.
• These accelerometers make use of the piezoresistive effect, a phenomenon that occurs when mechanical stress is applied and causes a change in a semiconductor or metal’s electrical resistance. An electrical signal is then produced by the accelerometer from the change.

Applications of accelerometer

An accelerometer is a piece of equipment used to measure a body’s acceleration. Both inertial navigation and guidance systems make extensive use of it. Other typical applications for accelerometers include:

• It plays a crucial role in the airbag deployment system of contemporary cars.
• It can be used to gauge seismic activity, vehicle velocity, or even inclination.
• It can be used to gauge how deeply to compress the chest during CPR.
• It can also be used to rotate the screen of a digital camera or a smartphone while displaying the images on the screen in an upright position.
• In a variety of modern electronics, accelerometers are crucial and active components.

Summary

An accelerometer is a sensor that allows us to track both linear and angular acceleration. The accelerometer operates on a pretty straightforward principle. An accelerometer, which measures numbers in one, two, or three planes, can be used to measure the acceleration force, or “g.” Capacitive accelerometers, piezoelectric accelerometers, and piezoresistance accelerometers are the three basic types of accelerometers. Accelerometers are used in a wide variety of scientific applications. The inertial navigation systems are most frequently used for aircraft or missiles.

Frequently Asked Questions

1. What is a gravimeter?

Ans: An accelerometer is known as a gravimeter when it has been expressly designed to be used in gravimetry, or to measure gravity.

2. What is the most common use of accelerometers?

Ans: Accelerometers are used in a wide variety of scientific applications. The inertial navigation systems are most frequently used for aircraft or missiles.

3. What are MEMS accelerometers?

Ans: Micro-electromechanical systems, or MEMS, are able to sense vibrations even at extremely small scales. To track changes in these electrical devices’ positions, they are mostly employed in a variety of portable gadgets.

4. How can an accelerometer be used for hard drive protection?

Ans: When a device experiences excessive acceleration or vibration, an accelerometer can identify it. It safeguards the hard disc in this case by emptying the reading heads to prevent contact with the pattern.

5. What are the key characteristics we need to keep in mind while selecting an accelerometer?

Ans: The sensor bandwidth, sensitivity, frequency response, and dynamic range of an accelerometer are some of the important properties we must take into account for a particular application.