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mpu9250

Connect MPU-9250 sensor on Raspberry Pi hardware I2C bus

Since R2021a

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Description

The mpu9250 object reads linear acceleration, angular velocity, and magnetic field along the X, Y, and Z axes using the InvenSense I2C-based MPU-9250 inertial measurement unit (IMU) sensor interfaced with the Raspberry Pi® hardware. Before you use the mpu9250 object, ensure that the I2C interface is enabled on your Raspberry Pi kernel. You can then create a connection to the Raspberry Pi board using the raspi object and set its properties. For more information, see raspi.

Creation

Syntax

sensor = mpu9250(mypi)
sensor = mpu9250(mypi,Name,Value)

Description

sensor = mpu9250(mypi) creates a MPU-9250 sensor object with default property values. The object represents a connection to the sensor on the Raspberry Pi hardware mypi.

example

sensor = mpu9250(mypi,Name,Value) creates a MPU-9250 sensor object with properties using one or more Name,Value arguments.

example

Input Arguments

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Raspberry Pi hardware board connection specified as a raspi object.

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

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

I2C bus address of the Raspberry Pi hardware board.

Example: sensor = mpu9250(mypi, 'Bus', 'i2c-1') creates the sensor object on the 'i2c-1' bus of the Raspberry Pi board.

Data Types: char

Specify the I2C address of the sensors when multiple I2C devices with the expected address for MPU9250 are connected to the same hardware board. MPU9250 can have multiple I2C addresses depending on the logic level on pin AD0 of the sensor.

Pin NamePin StateI2C Address
AD0Low[0x68, 0x0C]
High[0x69, 0x0C]

You can specify the I2C address in:

  • Numeric array of hexadecimal, decimal, or binary format of I2C Addresses

  • String array of hexadecimal value of I2C Addresses

  • Cell array of character vector of hexadecimal value of I2C Addresses

Example: imu = mpu9250(mypi,'I2CAddress',[0x68, 0x0C])

'0x69' is the I2C address of the accelerometer and gyroscope of MPU9250. '0x0C' is the I2C address of the magnetometer of MPU9250.

If not specified, the object will be created with one of the available I2C device address in the table. Availability of I2C device with the expected address will be determined by using scanI2CBus.

Object Functions

readAccelerationRead one sample of acceleration from sensor
readAngularVelocityRead one sample of angular velocity from sensor
readMagneticFieldRead one sample of magnetic field from sensor

Examples

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Ensure that the I2C interface on the Raspberry Pi kernel is enabled and then create an mpu9250 sensor object.

You can enable the I2C interface using:

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)

GPIO header pins I2C_SDA (GPIO 2) and I2C_SCL (GPIO 3) are used for I2C functionality. Display pin mapping of the Raspberry Pi hardware board.

showPins(mypi);
Raspberry Pi 3 Model B+ GPIO Pin Map diagram

Get the addresses of the MPU-9250 sensor connected to the I2C bus 'i2c-1'.

sensor = scanI2CBus(mypi,'i2c-1');
ans =

  1×2 cell array

    {'0x69'}    {'0xC'}

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

Extended Capabilities

Version History

Introduced in R2021a

See Also

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