Magnetometer Guide

Introduction

A compass is a navigational instrument that is used to determine direction relative to the surface of the earth. Compasses measure direction with respect to the 4 cardinal directions (North, East, South, West) with 0 degrees indicating straight North and 180 degrees indicating straight South.

Electronic compasses work in exactly the same way as any other compass: They detect the Earth's magnetic field and respond to it. The difference is that an electronic compass uses a magnetometer to detect the field as opposed to a small magnet. This allows them to be much more accurate and allows them to respond more quickly to changes in direction than a traditional compass ever could.

How Compasses Work

Small compasses found in clocks, mobile phones, and other electronic devices are solid-state compasses, usually built out of two or three magnetic field sensors that provide data for a microprocessor. The correct heading relative to the compass is calculated using trigonometry. Often, the device is a discrete component which outputs either a digital or analog signal proportional to its orientation. This signal is interpreted by a controller or microprocessor and used either internally, or sent to a display unit. The sensor uses highly calibrated internal electronics to measure the response of the device to the Earth's magnetic field.

Basic Use

Compasses are typically mounted on an object that the user wants to monitor the direction of. In order to get the most accurate readings it is recommended to mount the compass to the object in such a way that there is minimal room for shifting. You will need to calibrate the compass as well.

Calibration

Calibration involves setting the compass up to handle the magnetic field characteristics in your particular region of the world as well as disturbances caused by a more localized magnetic fields such as speaker magnets. To calibrate effectively you will need to determine the Earth's magnetic field strength at your location. This data is available on line in the form of magnetic field calculators all you have to do is enter in your zip or postal code.

Calibration is required for any applications needing more accuracy than North, East, South, West.

For more information on calibrating the compass on the 1056 refer to our calibration guide.