readMagneticField

Read one magnetic field data sample from MPU-9250 sensor

Syntax

[magReadings,timestamp] = readMagneticField(sensor)

Description

[magReadings,timestamp] = readMagneticField(sensor) returns one sample of the magnetic field data from the MPU-9250 IMU sensor. The magnetic field sample is returned as a 3-by-1 vector in μT (microtesla) along the X, Y, and Z axes. The function also returns the timestamp at which MATLAB^® receives the magnetic field data from the MPU-9250 sensor. The timestamp output is optional.

Note

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

Examples

Read Magnetic Field Data from MPU-9250 Sensor

Read the magnetic field data from the MPU-9250 IMU sensor on the X, Y, and Z axes.

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

mypi = raspi;

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 an mpu9250 sensor object on the I2C bus 'i2c-1' on addresses '0x69' and '0x0C'.

sensor = mpu9250(mypi,'Bus','i2c-1','I2CAddress',{'0x69','0x0C'});

sensor = 

  mpu9250 with properties:

                         I2CAddress: 105 ("0x69")
                                   : 12 ("0xC")
                                Bus: i2c-1 

Return one sample of magnetic field data read from the MPU-9250 I2C sensor on the X, Y, and Z axes.

[magReadings,timestamp] = readMagneticField(sensor);

magReadings =

  data

    9.6000    3.0000   16.2000

timestamp = 

  datetime

   10-Dec-2020 18:25:35.846

Since the timestamp output is optional, you can obtain only the magnetic field data from the MPU-9250 sensor.

[magReadings] = readMagneticField(sensor);

magReadings =

  data

    9.6000    3.0000   16.2000

Input Arguments

sensor — MPU-9250 sensor object

mpu9250 object

MPU-9250 sensor object connection to the Raspberry Pi hardware board, specified as a mpu9250 object.

Example: sensor = mpu9250(mypi) creates a connection to the MPU-9250 sensor on the Raspberry Pi object mypi.

Output Arguments

magReadings — Magnetic field values read from MPU-9250 sensor

3-by-1 vector magnetic field data

Read the magnetic field data from the MPU-9250 sensor on the X, Y, and Z axes.

timestamp — Timestamp of magnetic field values read from MPU-9250 sensor

datetime

Read the date and time at which MATLAB receives the magnetic field sample value from the MPU-9250 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 an mpu9250 sensor object and do not specify the I2C address in the name-value pair, the default I2C address is considered by the MPU-9250 sensor. For the MPU-9250 sensor, the default I2C address is {'0x68','0x0C'}.

• 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