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The fluctuation in the readings from a LIS3MDL sensor

Question asked by M. Jeong on Oct 11, 2017
Latest reply on Oct 13, 2017 by Miroslav B

I'm testing a LIS3MDL magnetic field sensor using an Arduino Pro mini. The Arduino IDE has a library for Pololu LIS3MDL module and example codes as well. I connected the sensor module to the Arduino via I2C and ran an example program. The program is supposed to read the magnitude of the magnetic field in x, y, z axes with the sensor and to send the readings to PC via UART. The program is working fine, except that I see fluctuations in the readings. The sensor module is laid on my desk and is about 1m from desktop. The following is a set of readings that I received from the sensor. 

M:    678   1720   2750
M:    701   1739   2784
M:    692   1754   2769
M:    684   1742   2833
M:    729   1733   2837
M:    671   1750   2742
M:    719   1757   2786
M:    739   1746   2762
M:    735   1742   2790
M:    675   1722   2734
M:    725   1696   2809
M:    733   1690   2772
M:    671   1726   2800
M:    670   1711   2764
M:    670   1726   2782
M:    706   1689   2793
M:    699   1713   2811
M:    725   1716   2766
M:    685   1724   2749
M:    707   1709   2736
M:    682   1733   2762
M:    705   1718   2784
M:    694   1710   2788
M:    710   1725   2755
M:    723   1713   2775
M:    719   1716   2746
M:    667   1700   2766
M:    698   1715   2782
M:    653   1711   2798
M:    714   1694   2765
M:    677   1705   2799
M:    669   1691   2783
M:    682   1722   2832
M:    698   1720   2787
M:    653   1747   2787
M:    698   1715   2727
M:    677   1714   2777
M:    647   1719   2724
M:    682   1713   2737
M:    685   1756   2790
M:    703   1745   2802
M:    687   1739   2745
M:    692   1736   2761
M:    670   1719   2766
M:    706   1752   2819
M:    720   1715   2822
M:    706   1727   2757
M:    675   1751   2857
M:    635   1752   2769
M:    732   1755   2813
M:    656   1743   2744
M:    660   1731   2828
M:    685   1777   2820
M:    674   1746   2797
M:    679   1799   2771

According to the library the range is +-4 gauss. Thus the amplitude of the fluctuation is about (100/6842) = 0.01gauss.

 

1. Is the fluctuation normal for the LSI3MDL? I wonder if it's an intrinsic property of the sensor.

 

2. Isn't it possible to have an accuracy of 1 degrees, when one measures the orientation with LIS3MDL? 

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