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Accelerometer Sensor Basics

accelerometer sensor mems acceleration measurements

This page describes the basic function of an Accelerometer sensor, its working principle, and its various applications.

What is an Accelerometer Sensor and How it Works?

Accelerometer schematic structure

Definition: An Accelerometer is a sensor that determines the direction a device is facing by sensing the acceleration of gravity. It’s typically developed using a MEMS (Micro-Electro-Mechanical Systems) design.

Most modern phones are equipped with accelerometers. This sensor device measures the proper acceleration of the device it’s installed in. It’s an electro-mechanical device that measures acceleration forces.

These forces can be either static or dynamic. Static refers to the constant force of gravity, while dynamic refers to the force produced by movement or vibration of the accelerometer.

Acceleration is defined as the change in velocity or speed divided by time. The sensor measures the component of acceleration due to gravity acting on each of the 3 axes. These components are trigonometrically related to the angle of inclination. When measuring large magnitudes of acceleration, on the order of 1 to 2 g, it’s also known as a strong motion sensor.

There are different types of Accelerometers, each with varying specifications. The appropriate accelerometer type is selected based on specific needs. These specifications include:

  • C: Number of components
  • F-Range: Frequency range over which the response is flat, available from DC to 800 Hz.
  • Out V: Maximum output voltage
  • In V: Supply voltage, e.g., 12V
  • I: Current consumption (mA)
  • G: Generator constant (V/ms-1 or V/g)
  • W: Weight of sensor
  • Dynamic Range: in dB
  • Resolution: in nm/s

Companies like NXP Semiconductors have developed various types of accelerometers such as 3-axis, 2-axis, and 1-axis versions. They also offer digital accelerometers which can be easily integrated with microcontroller and processor bus lines.

Accelerometer Sensor Applications

  • Used in both academic research and the consumer market.
  • Accelerometers in laptops protect the hard drive from damage in the event of a free fall.
  • Detects car crashes and deploys airbags almost instantaneously.
  • Determines the direction of tilt of the device where it is mounted or installed, such as tablets, e-readers, and smartphones.
  • Used in medical and home appliances.