HVAC Click

HVAC Click is a compact add-on board that contains Sensirion’s next-generation miniature CO2 sensor. This board features the SCD41, a carbon dioxide sensor build on the photoacoustic sensing principle, and Sensirion’s patented PASens® and CMOSens® technology to offer high accuracy at a minor form factor.

Click Product page

Click library

• Author : Stefan Ilic
• Date : Oct 2021.
• Type : I2C type

Software Support

We provide a library for the Hvac Click as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Library Description

This library contains API for Hvac Click driver.

Standard key functions :

• hvac_cfg_setup Config Object Initialization function.

  void hvac_cfg_setup ( hvac_cfg_t *cfg );

• hvac_init Initialization function.

  err_t hvac_init ( hvac_t *ctx, hvac_cfg_t *cfg );

Example key functions :

• hvac_sps30_start_measurement SPS30 start measurement command function.

  void hvac_sps30_start_measurement ( hvac_t *ctx );

• hvac_sps30_get_ready_flag SPS30 get ready flag function.

  uint8_t hvac_sps30_get_ready_flag ( hvac_t *ctx );

• hvac_sps30_read_measured_data SPS30 read measured data function.

  void hvac_sps30_read_measured_data ( hvac_t *ctx, mass_and_num_cnt_data_t *m_n_c_data );

Example Description

This is an example that demonstrates the use of the HVAC Click board.

The demo application is composed of two sections :

Application Init

Initialization driver enables - I2C, SCD40: perform factory reset, serial number, features, product type platform type, product version and SPS30: perform start measurement mode, also write log.

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    hvac_cfg_t hvac_cfg;  /**< Click config object. */

    /** 
     * Logger initialization.
     * Default baud rate: 115200
     * Default log level: LOG_LEVEL_DEBUG
     * @note If USB_UART_RX and USB_UART_TX 
     * are defined as HAL_PIN_NC, you will 
     * need to define them manually for log to work. 
     * See @b LOG_MAP_USB_UART macro definition for detailed explanation.
     */
    LOG_MAP_USB_UART( log_cfg );
    log_init( &logger, &log_cfg );
    log_info( &logger, " Application Init " );

    // Click initialization.
    hvac_cfg_setup( &hvac_cfg );
    HVAC_MAP_MIKROBUS( hvac_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == hvac_init( &hvac, &hvac_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }

    log_info( &logger, " Application Task " );
    Delay_ms ( 1000 );
    hvac_scd40_send_cmd( &hvac, HVAC_PERFORM_FACTORY_RESET );
    log_printf( &logger, "  Perform Factory Reset   \r\n" );
    log_printf( &logger, "--------------------------\r\n" );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );

    hvac_scd40_get_serial_number ( &hvac, ser_num );
    log_printf( &logger, "   SCD40 - Serial Number : %.4d-%.4d-%.4d \r\n", 
                ( uint16_t ) ser_num[ 0 ], ( uint16_t ) ser_num[ 1 ], ( uint16_t ) ser_num[ 2 ] );
    log_printf( &logger, "--------------------------\r\n" );
    Delay_ms ( 100 );
    hvac_scd40_get_feature_set_version( &hvac, &version_data );
    log_printf( &logger, "     SCD40 - Features     \r\n" );
    log_printf( &logger, " Product Type    : %d \r\n", ( uint16_t ) version_data.product_type );
    log_printf( &logger, " Platform Type   : %d \r\n", ( uint16_t ) version_data.platform_type );
    log_printf( &logger, " Product Version : %d.%d \r\n", 
                ( uint16_t ) version_data.product_major_version, 
                ( uint16_t ) version_data.product_minor_version );
    log_printf( &logger, "--------------------------\r\n" );
    Delay_ms ( 100 );

    hvac_sps30_start_measurement ( &hvac );
    Delay_ms ( 100 );
}

Application Task

This is an example which demonstrates the use of HVAC Click board. HVAC Click board can be used to measure : Concentration of CO2 in air, Temperature ( degree Celsius ), Relative Humidity ( % ), Mass Concentration of PM1.0, PM2.5, PM4.0, PM10 and Number Concentration of PM0.5, PM1.0, PM2.5, PM4.0 and PM10. All data logs write on USB uart changes.

void application_task ( void ) 
{
    hvac_scd40_send_cmd( &hvac, HVAC_MEASURE_SINGLE_SHOT );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );

    hvac_scd40_read_measurement( &hvac, &hvac_data );
    Delay_ms ( 100 );

    log_printf( &logger, " CO2 Concent = %d \r\n ", hvac_data.co2_concent );

    log_printf( &logger, " Temperature = %.2f C \r\n", hvac_data.temperature );

    log_printf( &logger, " R. Humidity = %.2f %% \r\n", hvac_data.r_humidity );
    log_printf( &logger, "- - - - - - - - - - - - -  \r\n" );

    while ( HVAC_SPS30_NEW_DATA_IS_READY != hvac_sps30_get_ready_flag( &hvac ) );


    log_printf( &logger, "   Mass Concentration :   \r\n" );
    hvac_sps30_read_measured_data( &hvac, &sps30_data );
    Delay_ms ( 100 );

    log_printf( &logger, " PM 1.0 = %.2f ug/m3 \r\n", sps30_data.mass_pm_1_0 );
    log_printf( &logger, " PM 2.5 = %.2f ug/m3 \r\n", sps30_data.mass_pm_2_5 );
    log_printf( &logger, " PM 4.0 = %.2f ug/m3 \r\n", sps30_data.mass_pm_4_0 );
    log_printf( &logger, " PM 10  = %.2f ug/m3 \r\n", sps30_data.mass_pm_10 );
    log_printf( &logger, "-   -   -   -   -   -   - \r\n" );

    log_printf( &logger, "  Number Concentration :  \r\n" );
    log_printf( &logger, " PM 0.5 = %.2f n/cm3 \r\n", sps30_data.num_pm_0_5 );
    log_printf( &logger, " PM 1.0 = %.2f n/cm3 \r\n", sps30_data.num_pm_1_0 );
    log_printf( &logger, " PM 2.5 = %.2f n/cm3 \r\n", sps30_data.num_pm_2_5 );
    log_printf( &logger, " PM 4.0 = %.2f n/cm3 \r\n", sps30_data.num_pm_4_0 );
    log_printf( &logger, " PM 10  = %.2f n/cm3 \r\n", sps30_data.num_pm_10 );
    log_printf( &logger, "--------------------------\r\n" );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
}

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Other Mikroe Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.Hvac

Additional notes and informations

Depending on the development board you are using, you may need USB UART Click, USB UART 2 Click or RS232 Click to connect to your PC, for development systems with no UART to USB interface available on the board. UART terminal is available in all MikroElektronika compilers.