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Connect to HTS221 sensor on Raspberry Pi hardware I2C bus


The hts221 object reads ambient temperature and relative humidity using the STMicroelectronics® I2C-based HTS221 sensor interfaced with the Raspberry Pi™ hardware. This object represents a connection from MATLAB® to the HTS221 sensor connected on the Raspberry Pi hardware board I2C pins I2C1_SDA (GPIO 2) and I2C1_SCL (GPIO 3). Before you use the hts221 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.




sensor = hts221(mypi) creates a HTS221 sensor object with default property values. The object represents a connection to the sensor on the Raspberry Pi hardware mypi.


sensor = hts221(mypi,Name,Value) creates a HTS221 sensor object with properties using one or more Name,Value arguments.

Input Arguments

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Raspberry Pi hardware board connection specified as a raspi object.

Example: sensor = hts221(mypi) creates a connection to the HTS221 sensor on the Raspberry Pi object mypi.

Name-Value Pair Arguments

Specify optional comma-separated pairs of Name,Value arguments. Name is the argument name and Value is the corresponding value. Name must appear inside quotes. You can specify several name and value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

I2C bus address of the Raspberry Pi hardware board.

Example: sensor = hts221(mypi, 'Bus', 'i2c-1') creates the HTS221 sensor object on 'i2c-1' bus of the Raspberry Pi board.

Data Types: char

Object Functions

readTemperatureRead one ambient temperature data sample from HTS221 sensor
readHumidityRead one relative humidity data sample from HTS221 sensor


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Ensure that the I2C interface on the Raspberry Pi kernel is enabled and then create an hts221 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.

Raspberry Pi Kernel I2C Interfacing options selection on Linux terminal

Select Yes when prompted to enable the I2C interface.

Raspberry Pi Kernel I2C Interfacing enabling options

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

Select Finish.

Select Yes when prompted to reboot.


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)

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.

Raspberry Pi 3 Model B+ GPIO Pin Map diagram

Get the address of the HTS221 sensor connected to the I2C bus 'i2c-1'.

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

  1×1 cell array


Create an hts221 sensor object on the I2C bus 'i2c-1' on address '0x5F'.

sensor = hts221(mypi,'Bus','i2c-1');
sensor = 

  hts221 with properties:

                         I2CAddress: 95 ("0x5F")
                                Bus: i2c-1

Extended Capabilities

Introduced in R2021a