lps22hb

Connect to LPS22HB sensor on Raspberry Pi hardware I2C bus

Since R2021a

Description

The lps22hb object reads ambient temperature and absolute pressure using the STMicroelectronics^® I2C-based LPS22HB sensor interfaced with the Raspberry Pi^® hardware. This object represents a connection from MATLAB^® to the LPS22HB sensor connected on the Raspberry Pi hardware board I2C pins I2C1_SDA (GPIO 2) and I2C1_SCL (GPIO 3). Before you use the lps22hb 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 = lps22hb(mypi)

sensor = lps22hb(mypi,Bus, I2CAddress)

Description

sensor = lps22hb(mypi) creates a LPS22HB sensor object with default property values. The object represents a connection to the sensor on the Raspberry Pi hardware mypi.

sensor = lps22hb(mypi,Bus, I2CAddress) creates a LPS22HB sensor object that represents a connection to the sensor connected to the I2C bus on the Raspberry Pi hardware mypi.

Input Arguments

mypi — Raspberry Pi hardware connection

raspi object

Raspberry Pi hardware board connection specified as a raspi object.

Example: sensor = lps22hb(mypi) creates a connection to the LPS22HB 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 = lps22hb(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 LPS22HB sensor

'0x5C' (default) | '0x5D'

I2C address of the LPS22HB sensor. This is the address of the sensor when multiple sensors are connected to the same hardware board. LPS22HB sensor has two peripheral addresses that depend on the logic level of pin SA0 of the sensor. For example, if the logic level of SA0 is low, the I2C address is '0x5C' and if the logic level of SA0 is high, the I2C address is '0x5D'.

Example: sensor = lps22hb(mypi,'I2CAddress','0x5D')

Data Types: string | integer | hexadecimal | binary | char

Object Functions

readTemperature	Read one ambient temperature data sample from LPS22HB sensor
readPressure	Read one absolute pressure data sample from LPS22HB sensor

Examples

Create LPS22HB Sensor Connection

Ensure that the I2C interface on the Raspberry Pi kernel is enabled and then create an lps22hb 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.

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)

Get the address of the LPS22HB sensor connected to the I2C bus 'i2c-1'.

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

ans =

  1×1 cell array

    {'0x5D'}

Create an lps22hb sensor object on the I2C bus 'i2c-1' on address '0x5D'.

sensor = lps22hb(mypi,'Bus','i2c-1','I2CAddress','0x5D');

sensor = 

  lps22hb with properties:

                         I2CAddress: 93 ("0x5D")
                                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 lps22hb sensor object and do not specify the I2C address in the name-value pair, the default I2C address is considered by the LPS22HB sensor. For the LPS22HB sensor, the default I2C address is '0x5C'.

Version History

Introduced in R2021a