The compass application on your smartphone somehow knows which direction the phone is pointing. Similarly, the stargazing application in your phone knows which part of the sky you are looking at, to display constellations correctly. Ever wondered how they do it? Smartphones and other mobile technologies identify their orientation with the help of a small device made up of axis-based motion sensing, and the device is known as an accelerometer. In this article, we will study accelerometer in detail.

What is Accelerometer?

An accelerometer is an electromechanical device that is used to measure acceleration forces. Such forces may be static like the force of gravity or, they may be dynamic as in the case of mobile devices.

How does an accelerometer work?

An accelerometer comes in the form of a simple circuit for a large electronic device. Despite the humble appearance, the accelerometer is made of different parts and works in many ways, two of which are the piezoelectric effect and the capacitance sensor.

  • The piezoelectric effect is the most popular form and uses microscopic crystal structures that get stressed due to accelerative forces. A voltage arises in the crystals from the stress, and the accelerometer translates this voltage to velocity and orientation.
    Piezoelectric Accelerometer
  • The capacitance accelerometer senses the changes in capacitance between microstructures. If the accelerative force moves one of these microstructures, the capacitance changes and the accelerometer translates this capacitance into voltage for interpretation.
  • Capacitive Accelerometer

  • Accelerometers are made of multiple axes – two to determine two-dimensional motion with an option for a third for 3D positioning. Smartphones make use of the three-axis model while cars make use of the two-axis to determine the moment of impact.

What is the use of accelerometer?

Applications of Accelerometer

The applications of accelerometer extend to multiple disciplines, following are a few of its uses:

  • Accelerometers in laptops protect the hard drive from damage. If the laptop were to fall while in use, the accelerometer would detect the fall and immediately turn off the hard drive to avoid hitting the reading heads into the hard drive platter.
  • Accelerometers in cars are used to detect car crashes and deploy airbags immediately.
  • Smartphones rotate their display between landscape and portrait mode depending on how one titles the phone.

Accelerometers are actively used in many electronics today, and it plays an active role in a wide range of functionalities. In many cases, the presence of this simple sensor is unnoticed, and the odds are that you may already be using a device with it.

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