Bmm150 - Magnetometer

The Bmm150 is a magnetometer that can be controlled either through I2C or through SPI. This implementation was tested in a ESP32 platform, specifically in an M5Stack Gray.

Documentation

Documentation for the Bmm150 can be found here

Usage

You can find an example in the sample directory. Usage is straight forward. The previous "Calibration" method was removed, as it would need to be completely rewritten to do something useful.

I2cConnectionSettings mpui2CConnectionSettingmpus = new(1, Bmm150.DefaultI2cAddress);

using Bmm150 bmm150 = new Bmm150(I2cDevice.Create(mpui2CConnectionSettingmpus));

while (!Console.KeyAvailable)
{
    MagnetometerData magne;
    try
    {
        magne = bmm150.ReadMagnetometer(true, TimeSpan.FromMilliseconds(11));
    }
    catch (Exception x) when (x is TimeoutException || x is IOException)
    {
        Console.WriteLine(x.Message);
        Thread.Sleep(100);
        continue;
    }

    Console.WriteLine($"Mag data: X={magne.FieldX}, Y={magne.FieldY}, Z={magne.FieldZ}, Heading: {magne.Heading}, Inclination: {magne.Inclination}");

    Thread.Sleep(500);
}

Expected output

Mag data: X=15.5 µT, Y=6.25 µT, Z=16.13 µT, Heading: 338.04 °, Inclination: 46.13 °
Mag data: X=18.44 µT, Y=4.75 µT, Z=13.56 µT, Heading: 345.55 °, Inclination: 36.34 °
Mag data: X=18.06 µT, Y=1.44 µT, Z=19.81 µT, Heading: 355.45 °, Inclination: 47.65 °
Mag data: X=17.69 µT, Y=1.44 µT, Z=15.44 µT, Heading: 355.35 °, Inclination: 41.11 °
Mag data: X=17.69 µT, Y=0 µT, Z=19.81 µT, Heading: 0 °, Inclination: 48.24 °
Mag data: X=17.69 µT, Y=-0.69 µT, Z=16.13 µT, Heading: 2.23 °, Inclination: 42.35 °
Mag data: X=18.81 µT, Y=0 µT, Z=19.06 µT, Heading: 0 °, Inclination: 45.38 °
Mag data: X=16.63 µT, Y=-1.44 µT, Z=18 µT, Heading: 4.94 °, Inclination: 47.27 °
Mag data: X=17.69 µT, Y=-1.44 µT, Z=16.5 µT, Heading: 4.65 °, Inclination: 43.01 °
Mag data: X=17.69 µT, Y=0.69 µT, Z=20.94 µT, Heading: 357.77 °, Inclination: 49.81 °
Mag data: X=18.06 µT, Y=-0.31 µT, Z=15.44 µT, Heading: 0.99 °, Inclination: 40.52 °
Mag data: X=17 µT, Y=4.38 µT, Z=20.56 µT, Heading: 345.57 °, Inclination: 50.42 °
Mag data: X=16.63 µT, Y=8.5 µT, Z=18 µT, Heading: 332.92 °, Inclination: 47.27 °
Mag data: X=14 µT, Y=10.69 µT, Z=17.63 µT, Heading: 322.64 °, Inclination: 51.54 °
Mag data: X=14.75 µT, Y=8.5 µT, Z=17.25 µT, Heading: 330.05 °, Inclination: 49.47 °

Calibration

To calibrate a compass, you need to calculate the deviation table. See Iot.Device.Nmea0183.MagneticDeviationCorrection for a class to create an automatic deviation table.

Not supported/implemented features of the Bmm150

• Device Self-Tests
• Device Reset
• Toggle operation modes (defaults to normal mode)

Notes

• The BMI160 embeds this BMM150.