readMagneticField

Read one sample of magnetic field from sensor

Syntax

[magReadings,timestamp] = readMagneticField(sensorobj)

Description

[magReadings,timestamp] = readMagneticField(sensorobj) returns one sample of the magnetic field data on x, y, and z axes read from the sensor in units of µT (microtesla) along with the timestamp. Timestamp is optional.

Note

• The readMagneticField function is available for the MPU9250, LSM9DS1, LSM303C, and ICM20948 sensors.

• To generate C/C++ code for this function, you must have an Embedded Coder^® license.

Examples

Read Magnetic Field

Create a connection from MATLAB^® to the Raspberry Pi^® hardware board.

mypi = raspi('raspberrypi-hysdu8X38o','rocky','bullwinkle')

mypi = 

  Raspi with Properties:

           DeviceAddress: 'raspberrypi-hysdu8X38o'
                    Port: 18734
               BoardName: 'Raspberry Pi 3 Model B+'
           AvailableLEDs: {'led0'}
    AvailableDigitalPins: [4,5,6,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27]
    AvailableSPIChannels: {‘CE0’,’CE1’}
       AvailableI2CBuses: {'i2c-1'}
             I2CBusSpeed: 100000
        AvailabelWebCams: mmal service 16.1 (platform:bcm2835-v4l2)

Create the sensor object for the sensor in use.

Note

The sample code and output in this example is for lsm9ds1 object. If you are using another sensor that supports readMagneticField function, use the corresponding sensor object.

sensorobj = lsm9ds1(mypi,'Bus','i2c-1','I2CAddress',{'0x6A','0x1C'});

sensorobj = 

  lsm9ds1 with properties:

                         I2CAddress: 106 ("0x6A")
                                   : 28 ("0x1C")
                                Bus: i2c-1 

Return one sample of magnetic field data read from the sensor on the X, Y, and Z axes.

[magReadings,timestamp] = readMagneticField(sensor);

magReadings =

  data

    9.1980    7.0980  -52.9480


timestamp = 

  datetime

   9-Dec-2020 16:13:28.573

Since the timestamp output is optional, you can obtain only the magnetic field data from the sensor.

[magReadings] = readMagneticField(sensor);

magReadings =

  data

    9.1980    7.0980  -52.9480

Input Arguments

sensorobj — Sensor object

char

The sensor object.

Output Arguments

magReadings — Value read from the sensor

scalar

The magnetic field value on x, y, and z axes read from the sensor.

timestamp — Timestamp

datetime

The time at which MATLAB receives magnetic field data from the sensor, specified as a datetime.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

• Timestamp value is always returned in seconds.

• When you create a sensor object and do not specify the I2C address in the name-value pair, the default I2C address is considered by the sensor.

• To generate C/C++ code for this function, you must have an Embedded Coder license. For more information on selecting the right product stack according to your development goals, see Product Stack for Raspberry Pi Blockset.

Version History

Introduced in R2021a