DHT22 2 Click

DHT22 2 Click is used for measuring the environmental temperature and relative humidity. It uses the AM2322 sensor, with very accurate thermal and humidity measuring capabilities. It can use either 1-Wire or I2C protocol to communicate with the integrated circuit.

Click Product page

Click library

• Author : MikroE Team
• Date : maj 2020.
• Type : I2C type

Software Support

We provide a library for the Dht222 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 form compilers IDE(recommended way), or downloaded from our LibStock, or found on mikroE github account.

Library Description

This library contains API for Dht222 Click driver.

Standard key functions :

• dht222_cfg_setup Config Object Initialization function.

  void dht222_cfg_setup ( dht222_cfg_t *cfg ); 

• dht222_init Initialization function.

  err_t dht222_init ( dht222_t *ctx, dht222_cfg_t *cfg );

Example key functions :

• dht222_read_reg This function reads data from the desired register.

  err_t dht222_read_reg ( dht222_t *ctx, uint8_t address, uint8_t *data_out, uint8_t len );

• dht222_write_reg This function writes data to the desired register.

  err_t dht222_write_reg ( dht222_t *ctx, uint8_t address, uint8_t *data_in, uint8_t len );

• dht222_get_temp_hum The function reads the temperature and humidity data from the sensor AM2322 on the DHT22 2 Click.

  err_t dht222_get_temp_hum ( dht222_t *ctx, uint16_t *temperature, uint16_t *humidity );

Examples Description

This example demonstrates the use of DHT22 2 Click board by reading the temperature and humidity data.

The demo application is composed of two sections :

Application Init

Initializes the driver and logger.

void application_init ( void )
{
    log_cfg_t log_cfg;
    dht222_cfg_t cfg;

    /** 
     * 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.
    dht222_cfg_setup( &cfg );
    DHT222_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    dht222_init( &dht222, &cfg );
    Delay_ms ( 500 );
}

Application Task

Reads the temperature (degrees C) and the relative humidity (%RH) data and displays the results on the USB UART approximately once per second.

void application_task ( void )
{
    uint16_t temperature = 0;
    uint16_t humidity = 0;
    if ( DHT222_OK == dht222_get_temp_hum ( &dht222, &temperature, &humidity ) )
    {
        log_printf( &logger, " Humidity   : %.1f %%\r\n", ( float ) humidity / 10 );
        log_printf( &logger, " Temperature: %.1f C \r\n", ( float ) temperature / 10 );
        log_printf( &logger, "---------------------\r\n" );
        Delay_ms ( 1000 );
    }
}

The full application code, and ready to use projects can be installed directly form compilers IDE(recommneded) or found on LibStock page or mikroE GitHub accaunt.

Other mikroE Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.Dht222

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. The terminal available in all Mikroelektronika compilers, or any other terminal application of your choice, can be used to read the message.