lsm9ds1

Connect to LSM9DS1 sensor on Raspberry Pi hardware I2C bus

Since R2021a

Description

The lsm9ds1 object reads linear acceleration, angular velocity, and magnetic field along the X, Y, and Z axes using the STMicroelectronics^® I2C-based LSM9DS1 inertial measurement unit (IMU) sensor interfaced with the Raspberry Pi^® hardware. This object represents a connection from MATLAB^® to the LSM9DS1 sensor connected on the Raspberry Pi hardware board I2C pins I2C1_SDA (GPIO 2) and I2C1_SCL (GPIO 3). Before you use the lsm9ds1 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 enableI2C and raspi.

Creation

Syntax

sensor = lsm9ds1(mypi)

sensor = lsm9ds1(mypi,Name,Value)

Description

sensor = lsm9ds1(mypi) creates a LSM9DS1 sensor object with default property values. The object represents a connection to the sensor on the Raspberry Pi hardware, mypi.

sensor = lsm9ds1(mypi,Name,Value) creates a LSM9DS1 sensor object with properties using one or more Name,Value arguments.

Input Arguments

mypi — Raspberry Pi hardware connection

raspi object

Raspberry Pi hardware board connection specified as a raspi object.

Example: sensor = lsm9ds1(mypi) creates a connection to the LSM9DS1 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.

Bus — I2C bus address of Raspberry Pi board

'i2c-0' | 'i2c-1'

I2C bus address of the Raspberry Pi hardware board.

Example: sensor = lsm9ds1(mypi, 'Bus', 'i2c-0') creates the sensor object on the 'i2c-0' bus of the Raspberry Pi board.

Data Types: char

I2CAddress — I2C address of LSM9DS1 sensor

{'0x6B','0x1E'} (default) | {'0x6A','0x1C'} | {'0x6A','0x1E'} | {'0x6B','0x1C'}

I2C address of the LSM9DS1 sensor. This is the address of the sensor when multiple sensors are connected to the same hardware board. LSM9DS1 has two peripheral addresses that depend on the logic level of pins SDO_A/G and SDO_M of the sensor.

SDO_A/G Pin State	SDO_M Pin State	I2C Address of Sensor
Low	Low	{'0x6A','0x1C'}
Low	High	{'0x6A','0x1E'}
High	Low	{'0x6B','0x1C'}
High	High	{'0x6B','0x1E'}

You can specify the I2C address in hexadecimal, decimal, or binary format.

Example: sensor = lsm9ds1(mypi,'I2CAddress',{'0x6A','0x1C'}), where '0x6A' is the I2C address of the accelerometer and gyroscope of LSM9DS1 and '0x1C' is the I2C address of the magnetometer of the LSM9DS1 sensor.

Data Types: numeric array | string array | cell array

Object Functions

readAcceleration	Read one acceleration data sample from LSM9DS1 sensor
readAngularVelocity	Read one angular velocity data sample from LSM9DS1 sensor
readMagneticField	Read one magnetic field data sample from LSM9DS1 sensor

Examples

Create LSM9DS1 Sensor Connection

Ensure that the I2C interface on the Raspberry Pi kernel is enabled and then create an lsm9ds1 sensor object. Follow these steps to enable the I2C interface in the Raspberry Pi hardware kernel.

Open the Raspberry Pi Linux^® terminal.

Open the Raspberry Pi Software Configuration Tool dialog box.

sudo raspi-config

Select Interfacing Options > I2C.

Select Yes when prompted to enable the I2C interface.

Select Yes when prompted to automatically load the I2C kernel module.

Select Finish.

Select Yes when prompted to reboot.

Tip

You can also enable the I2C interface using the Raspberry Pi Resource Monitor App. For more information, see Enabling External Peripherals on Raspberry Pi Hardware Kernel.

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)

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);

Get the addresses of the LSM9DS1 sensor connected to the I2C bus 'i2c-1'.

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

ans =
 

  1×2 cell array
 

    {'0x6A'}    {'0x1C'}

Create an lsm9ds1 sensor object on the I2C bus 'i2c-1' on addresses '0x6A' and '0x1C'.

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

sensor = 

  lsm9ds1 with properties:

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

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 lsm9ds1 sensor object and do not specify the I2C address in the name-value pair, the default I2C address is considered by the LSM9DS1 sensor. For the LSM9DS1 sensor, the default I2C address is {'0x6B','0x1E'}.

Version History

Introduced in R2021a