dht22

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DHT22 Click

DHT22 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 : MikroE Team
• Date : May 2020.
• Type : GPIO type

Software Support

Example Description

This is a example which demonstrates the use of DHT22 Click board by measuring temperature and relative humidity.

Example Libraries

• MikroSDK.Board
• MikroSDK.Log
• Click.Dht22

Example Key Functions

• dht22_cfg_setup Config Object Initialization function.

void dht22_cfg_setup ( dht22_cfg_t *cfg );

• dht22_init Initialization function.

err_t dht22_init ( dht22_t *ctx, dht22_cfg_t *cfg );

• dht22_get_measurement_data DHT22 get measurement data from the sensor function.

err_t dht22_get_measurement_data ( dht22_t *ctx, float *humidity, float *temperature );

• dht22_start_signal DHT22 sends start signal to the sensor function.

void dht22_start_signal ( dht22_t *ctx );

• dht22_check_sensor_response DHT22 release the bus to wait the sensor response signal function.

uint8_t dht22_check_sensor_response ( dht22_t *ctx );

Application Init

Initializes the SDA data pin depending on the selected GPIO pin (SDA1/SDA2) and log module.

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    dht22_cfg_t dht22_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.
    dht22_cfg_setup( &dht22_cfg );
    DHT22_MAP_MIKROBUS( dht22_cfg, MIKROBUS_1 );

   if ( DIGITAL_OUT_UNSUPPORTED_PIN == dht22_init( &dht22, &dht22_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }

    log_info( &logger, "---- Application Init done. ----" );
}

Application Task

Reads the temperature and humidity from the sensor and displays the values on the USB UART.

void application_task ( void )
{
    static float temperature = 0;
    static float humidity = 0;
    
    dht22_init_sda_output( &dht22 );
    if ( DHT22_OK == dht22_start_signal( &dht22 ) )
    {
        dht22_init_sda_input( &dht22 );
        if ( DHT22_OK == dht22_check_sensor_response( &dht22 ) )
        {
            if ( DHT22_OK == dht22_get_measurement_data( &dht22, &humidity, &temperature ) )
            {
                log_printf( &logger, " Humidity : %.2f %%\r\n", humidity );
                log_printf( &logger, " Temperature : %.2f degC\r\n", temperature );
                log_printf( &logger, " ---------------------------\r\n" );
                Delay_ms ( 1000 );
            }
        }
    }
}

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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