Smartphone sensors and what they do

Ever wondered how your smartphone adjusts display brightness automatically, or even how the screen turns off when you pick/make a call? Well, smartphones have changed a lot since their inception. For them to serve us efficiently, smartphones are packed with sensors. Pretty much like our senses, these smartphone sensors collect information, and then the smartphone acts accordingly to the data.

Today’s high-end flagships have a lot of sensors for more functionality. The common thing between them and their low end and mid end counterparts is the basic sensors. These sensors are fundamental to every smartphone’s activity. They include; Proximity sensor, Ambient Light sensor, GPS, Accelerometer, and Gyroscope.

Proximity Sensor

If you look closely near the earpiece, you might notice something apart from the camera. It’s either the location of the proximity sensor or the ambient light sensor. As the name suggests, the proximity sensor determines how close your smartphone is in relation to an object; including you. It uses infrared(IR) or capacitative detectors. It produces a beam of IR which is invisible, when it hits an object it is reflected back and picked up by the sensor. This sensor is responsible for turning the screen off when you pick a call.

Ambient Light Sensor

This sensor collects information on the light conditions of your smartphone. If the environment is bright, the screen will be bright and vice versa. Smartphones that lack this sensor will not adjust display brightness automatically. High-end flagships use this sensor to fine tune how images are displayed on their screens.

GPS Sensor

This is the most well-known sensor; Precisely, it’s more of a receiver. The Global Positioning System (GPS) receiver uses satellites to provide geolocation information and time. This receiver usually connects to more than three satellites for accurate information. The GPS receiver in our smartphones also works by connecting to cell towers and WIFI. GPS is mostly used for navigation and location purposes. Applications such as Maps rely on it extensively; it’s a must have feature.


Unlike what you might be thinking, the accelerometer sensor in smartphones is used for orientation purposes. It measures your phones acceleration in relation to earth’s gravity; free fall. It’s involved with the directional movement of the device. It’s made up of a micro electro mechanical system which measures the acceleration. The sensor is used to determine whether to orient the screen in a portrait mode or landscape mode. Other applications use it to execute commands such as shake to cut/change music or even connect to other devices. The accelerometer can also work with other sensors for a greater purpose such as the magnetometer and gyroscope. When working with the gyroscope, lateral orientation is also provided.


As said earlier, some sensors are better when they form a team. A gyroscope is also used for orientation but when velocity is involved. It’s more precise than the accelerometer. In more technical terms, a gyroscope measures angular rotational velocity whereas the accelerometer is used for linear movements. Both the gyroscope and accelerometer use a 3-axis plane for effectiveness.

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