Compass Sensor – Working and Applications

From years unknown, navigation has helped in the growth of civilizations. New places were discovered, trades have begun and all of this was possible when people began to navigate from one place to another. New methods were also invented to make navigation easy. With the passage of time, the means of navigations have developed and modernized. Through all these changing years one technology that remained consistent to help in navigation is Compass. Today compass is highly modernized and applied for new applications. Both analog and digital forms of the compass were developed. Compass Sensor can also be found in smartphones and many mobile devices.

What is a Compass Sensor?

The invention of the compass date’s back to the 2nd century.  It was used by the Chinese for divination and alignment of building materials during construction. It was in the 11th century that people started using Compass for finding directions during navigation.

Compass sensor is the device whose function is to give the right directions with respect to the North and South magnetic poles of the earth. The needle present on a compass always points towards the geometric North of Earth. This device makes use of principles of magnetism for operation.

But this magnetic force of the earth is so weak that people previously used to design compass by suspending a thin magnetic strip. In the Compass present in smartphones magnet is not used as a component because it causes interference in communication.

Digital Compass Sensor
Digital Compass Sensor

Digital Compass Sensor is actually a magnetometer that can measure the Earth’s magnetic field. With the use of ‘Hall Effect’ and by calculating the ultralow frequency signals coming from the North or South direction, this sensor can calculate the orientation and direction.

Working Principle

The first compass used in the 11th century was a simple structure with a bowl of water containing a magnetic needle floating on it. Later many improved and reliable versions were developed. Digital Compass Sensor that is used in the smartphone is based on the magnetometer sensor.


The resistance of the magnetic sensor present in magnetometer changes in proportional to the magnetic field present in a particular direction. The magnetometer measures the magnetic field strength and orientation.

This information from magnetometer is stored by the CPU as digital data. This Sensor always points towards the Geometric North. The Compass found in electric devices is a solid-state sensor. Usually, two or three magnetic sensors are present on the device from which the microprocessor can read data and detects the orientation of the device.

Magnetic Compass Sensor

There are two configurations of Compass Sensors available based on there working principle. They are the Magnetic Compass and Gyro Compass. Magnetic Compass contains a magnetic element to detect the magnetic field. This magnetic element aligns itself with magnetic lines of Earth’s magnetic field.

Magnetic Compass points towards the magnetic pole Earth. Whereas Gyro compass points towards the true poles of the earth. Gyro compass consists of a rapidly spinning wheel.


Compass sensors were adopted by Western Europe and the Islamic World for navigation in the early 11th century. Besides navigation of voyages, today this Sensor is used for a wide range of applications.

Compass Sensor is the most reliable device for navigation. location and finding direction. It is highly useful for trekkers to find direction. Compass sensors are used in aviation and military applications. In construction, the compass sensor is used to align building material.

For divers, submarines and Marine force Compass Sensor is an everyday tool.

Compass Sensor in Andriod

To get the functionality of Compass on Android, the device must have a magnetometer. Compass Sensor app. installed on the device make use of data provided by the magnetometer to calculate orientation and direction and display a digital compass on the screen. By this, the phone can detect North and auto-rotate Google map according to our physical direction.

As this Sensor depends on the information provided by a magnetometer, to get a Compass Sensor without Magnetic Sensor is not possible. In such a situation, one can get the information about the direction using Google Maps as those operate using GPS and it doesn’t require a magnetic sensor.

There are many apps available for digital Compass Sensor for Android. For hardware installation, many digital Magnetometers are available in the market in the form of small IC’s. These IC’s are easy to interface with microcontrollers. These Sensors have also found their application in robotics. What happens when Compass Sensor is used near ferromagnetic substances?