environment4

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Environment 4 Click

Environment 4 Click demo application is developed using the NECTO Studio, ensuring compatibility with mikroSDK's open-source libraries and tools. Designed for plug-and-play implementation and testing, the demo is fully compatible with all development, starter, and mikromedia boards featuring a mikroBUS™ socket.

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Click Library

• Author : Stefan Filipovic
• Date : Dec 2022.
• Type : I2C type

Software Support

Example Description

This example demonstrates the use of Environment 4 Click board by reading the temperature and humidity data and calculating VOC and NOx indexes.

Example Libraries

• MikroSDK.Board
• MikroSDK.Log
• Click.Environment4

Example Key Functions

• environment4_cfg_setup Config Object Initialization function.

void environment4_cfg_setup ( environment4_cfg_t *cfg );

• environment4_init Initialization function.

err_t environment4_init ( environment4_t *ctx, environment4_cfg_t *cfg );

• environment4_sht_read_meas_hp This function reads the temperature and humidity measurements with high precision from SHT41A device.

err_t environment4_sht_read_meas_hp ( environment4_t *ctx, float *temp, float *hum );

• environment4_sgp_exe_conditioning This function executes conditioning command for SGP41 device by using I2C serial interface.

err_t environment4_sgp_exe_conditioning ( environment4_t *ctx, uint16_t comp_rh, uint16_t comp_t, uint16_t *sraw_voc );

• environment4_sgp_meas_raw_signals This function measures raw signals for SGP41 device by using I2C serial interface.

err_t environment4_sgp_meas_raw_signals ( environment4_t *ctx, uint16_t comp_rh, uint16_t comp_t, uint16_t *sraw_voc, uint16_t *sraw_nox );

Application Init

Initializes the driver, and reads and displays the SGP41 sensor unique serial number and performs its build-in self-test. After that performs the SHT41 sensor software reset and reads its unique serial number. Finally, it initializes the sensirion gas index algorithm for VOC and NOx index calculation.

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    environment4_cfg_t environment4_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.
    environment4_cfg_setup( &environment4_cfg );
    ENVIRONMENT4_MAP_MIKROBUS( environment4_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == environment4_init( &environment4, &environment4_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    uint16_t serial_num_sgp[ 3 ];
    if ( ENVIRONMENT4_OK == environment4_sgp_get_serial_num ( &environment4, serial_num_sgp ) )
    {
        log_printf ( &logger, " SGP Serial number: 0x%.4X%.4X%.4X\r\n", 
                     serial_num_sgp[ 0 ], serial_num_sgp[ 1 ], serial_num_sgp[ 2 ] );
    }
    
    uint8_t test_result_sgp;
    if ( ENVIRONMENT4_OK == environment4_sgp_exe_self_test ( &environment4, &test_result_sgp ) )
    {
        log_printf ( &logger, " SGP Self test result: " );
        if ( ENVIRONMENT4_SGP_SELF_TEST_OK == test_result_sgp )
        {
            log_printf ( &logger, "OK\r\n" );
        }
        else
        {
            if ( ENVIRONMENT4_SGP_SELF_TEST_VOC_PIXEL == test_result_sgp )
            {
                log_printf ( &logger, "VOC pixel fail; " );
            }
            if ( ENVIRONMENT4_SGP_SELF_TEST_NOX_PIXEL == test_result_sgp )
            {
                log_printf ( &logger, "NOx pixel fail; " );
            }
            log_printf ( &logger, "\r\n" );
        }
    }
    
    if ( ENVIRONMENT4_OK == environment4_sht_soft_reset ( &environment4 ) )
    {
        log_printf ( &logger, " SHT Software reset\r\n" );
        Delay_1sec ( );
    }
    
    uint32_t serial_num_sht;
    if ( ENVIRONMENT4_OK == environment4_sht_read_serial_num ( &environment4, &serial_num_sht ) )
    {
        log_printf ( &logger, " SHT Serial number: 0x%.8LX\r\n", serial_num_sht );
    }
    
    log_printf ( &logger, " Initialize Gas Index algorithm for VOC and NOx\r\n" );
    GasIndexAlgorithm_init ( &voc_params, GasIndexAlgorithm_ALGORITHM_TYPE_VOC );
    GasIndexAlgorithm_init ( &nox_params, GasIndexAlgorithm_ALGORITHM_TYPE_NOX );
    
    log_info( &logger, " Application Task " );
}

Application Task

Reads the temperature (degC) and the relative humidity (%RH) data from SHT41 sensor with high precision. For the first 10 seconds it executes NOx conditioning and after that it reads the raw signals for VOC and NOx data and processes them with sensirion's gas index algorithm for calculating VOC and NOx indexes. All data will be displayed on the USB UART approximately once per second.

void application_task ( void )
{
    float temperature, humidity;
    uint16_t comp_rh, comp_t, sraw_voc, sraw_nox;
    int32_t voc_index, nox_index;
    static uint8_t conditioning_num = 10;
    Delay_ms ( 1000 );
    if ( ENVIRONMENT4_OK == environment4_sht_read_meas_hp ( &environment4, &temperature, &humidity ) )
    {
        log_printf ( &logger, "\r\n Temperature: %.2f degC\r\n", temperature );
        log_printf ( &logger, " Humidity: %.2f %%RH\r\n", humidity );
        
        comp_rh = ( uint16_t ) ( humidity * ENVIRONMENT4_SHT_DATA_RESOLUTION / 
                                 ( ENVIRONMENT4_SHT_ABS_MAX_HUM - ENVIRONMENT4_SHT_ABS_MIN_HUM ) );
        comp_t = ( uint16_t ) ( ( temperature - ENVIRONMENT4_SHT_ABS_MIN_TEMP ) * ENVIRONMENT4_SHT_DATA_RESOLUTION / 
                                ( ENVIRONMENT4_SHT_ABS_MAX_TEMP - ENVIRONMENT4_SHT_ABS_MIN_TEMP ) );
        if ( conditioning_num ) 
        {
            if ( ENVIRONMENT4_OK == environment4_sgp_exe_conditioning ( &environment4, comp_rh, comp_t, &sraw_voc ) )
            {
                conditioning_num--;
            }
        } 
        else 
        {
            if ( ENVIRONMENT4_OK == environment4_sgp_meas_raw_signals ( &environment4, comp_rh, comp_t, &sraw_voc, &sraw_nox ) )
            {
                GasIndexAlgorithm_process( &voc_params, ( int32_t ) sraw_voc, &voc_index );
                GasIndexAlgorithm_process( &nox_params, ( int32_t ) sraw_nox, &nox_index );
                log_printf ( &logger, " VOC Index: %ld\r\n", voc_index );
                log_printf ( &logger, " NOx Index: %ld\r\n", nox_index );
            }
        }
    }
}

Note

Time required for reliably detecting VOC and NOx events on switching ON is typically less than 60 seconds. Refer to the SGP41 sensor datasheet for more timing specifications.

Application Output

This Click board can be interfaced and monitored in two ways:

• Application Output - Use the "Application Output" window in Debug mode for real-time data monitoring. Set it up properly by following this tutorial.
• UART Terminal - Monitor data via the UART Terminal using a USB to UART converter. For detailed instructions, check out this tutorial.

Additional Notes and Information

The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.

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