How an accelerometer in a smartphone works to track your movements

Of all the components of a smartphone, the accelerometer probably holds the title of the most technologically fascinating, yet also underrated gadget on the device. When you want an image to be landscape or portrait on your phone, just turn the phone in the direction you want and the screen will follow you. Have you ever wondered how the phone recognized that you tilted it in that direction?

In order to respond to the rotation of the phone, it must detect in which direction you are moving it. An accelerometer is a great way to do this, and they come in all shapes and sizes. Despite this, accelerometers generally contain the same three variables:

• The accelerometer housing that moves with the device in which it is installed. This acts as the base of the sensor which moves at the same speed as the device.
• The moving part of the accelerometer that moves as the case moves around it. This movement depends on the inclination of the device.
• Sensors on the accelerometer that look at the moving part and monitor the movement of the device based on the result.

These are two very complicated words, but don't worry – they are quite simple in practice! First, let's explore capacitance accelerometers.

Do you know those physical ball maze toys you sometimes find in Christmas cookies? Imagine one of these, but it's just an empty square with no obstacles. Imagine that you have also connected the sides of the square to detect when the metal ball hits the sides. When you tilt the square, the ball rolls and hits one of the sides, triggering the sensor.

Of course, cell phones do not contain small marble maze puzzles! What they have, however, is something similar. Instead of a ball, the phone uses a grid suspended on brackets. These mounts have a bit of leniency, allowing the grille to move slightly as the phone moves.

Between the sections of the grid are small "fingers" that detect where the grid is. When the phone tilts, the grid moves on its supports towards the movement, and the fingers detect this movement. Fingers indicate which way the phone has tipped.

What are piezoelectric accelerometers?

On the other hand, piezoelectric accelerometers get their name from the piezoelectric effect, which the accelerometer uses to measure orientation.

Imagine if I had you standing with your back against the wall, holding a mattress at arm's length, eyes closed. I would then ask you to let me know if you notice the mattress moving. You can't see the mattress, but you can feel how it moves.

Now, if I push or pull on the mattress, it puts stress on your arms. Either you feel the mattress being pulled or pushed towards you. From that feeling alone, you can tell if I'm pulling or pushing the mattress.

Piezoelectric accelerometers work the same way. They use a mechanism that pushes and pulls against a crystal, which in turn emits electricity depending on the stress applied. This constraint is then translated into motion measurements.

Tilt and rotation

Accelerometers are an amazing and intriguing part of a smartphone, but they're sadly underrated. Now you know how they work and how they detect the direction of your phone.

How important is the accelerometer in your own phone? Let us know below.

Image credit:Wikipedia