The Influence of Different Materials on the Magnetometer Operation

This article deals with magnetometry and magnetometers, which are used for the detection and measurement of magnetic fields. The HMC2003 magnetoresistive magnetometer in this article is used to measure components of the Earth's magnetic field in the application for determining magnetic North. This article presents the basic principles of measuring the components of the Earth's magnetic field, the effects of basic groups of magnetic and nonmagnetic materials on the resulting components of the magnetic field and the resulting value of the magnetic azimuth. Another benefit is the application of the mathematical apparatus necessary to measure the components of the magnetic field in the measuring chain, which includes the main elements such as the Arduino UNO development board, 24-bit analog-to-digital converter ADS1256 (Analog Devices) and the Arduino IDE environment. An inseparable contribution of the article is also an innovative view on the calibration of the HMC2003 magnetometer, for determining its basic parameters, such as the offsets and the scale factors of the magnetometer, compensation of the influence of magnetically hard objects on the operation of the magnetometer. One of the main benefits is also the design of the SET-RESET circuit for restoring the properties of the magnetically sensitive part of the HMC2003 sensor, which was implemented in the measuring chain. In terms of assessing the effects of various materials and objects on magnetometer measurements, various paramagnetic, diamagnetic, ferromagnetic samples, neodymium magnet B52 and a mobile device - a smartphone - were chosen.