Air quality click

Air quality click carries an MQ-135 sensor for detecting poisonous gases that impact air quality in homes and offices. The click is designed to run on a 5V power supply. It communicates with the target microcontroller over the AN pin on the mikroBUS™ line.

click Product page

Click library

• Author : Jelena Milosavljevic
• Date : Jun 2021.
• Type : ADC type

Software Support

We provide a library for the airquality 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 airquality Click driver.

Standard key functions :

• airquality_cfg_setup Config Object Initialization function.

  void airquality_cfg_setup ( airquality_cfg_t *cfg );

• airquality_init Initialization function.

  AIRQUALITY_RETVAL airquality_init ( airquality_t *ctx, airquality_cfg_t *cfg );

Example key functions :

• airquality_read_an_pin_value This function reads results of AD conversion of the AN pin.

  err_t airquality_read_an_pin_value ( airquality_t *ctx, uint16_t *data_out );

• airquality_read_an_pin_voltage This function reads results of AD conversion of the AN pin and converts them to proportional voltage level.

  err_t airquality_read_an_pin_voltage ( airquality_t *ctx, float *data_out );

Example Description

The demo application shows the reading of the adc values given by the sensors.

The demo application is composed of two sections :

Application Init

Configuring clicks and log objects.

void application_init ( void ) {
    log_cfg_t log_cfg;  /**< Logger config object. */
    airquality_cfg_t airquality_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.

    airquality_cfg_setup( &airquality_cfg );
    AIRQUALITY_MAP_MIKROBUS( airquality_cfg, MIKROBUS_1 );
    if ( airquality_init( &airquality, &airquality_cfg ) == ADC_ERROR ) {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }
    airquality_default_cfg ( &airquality );
    log_info( &logger, " Application Task " );
}

Application Task

Reads the adc value and prints in two forms (DEC and HEX).

void application_task ( void ) {
    uint16_t airquality_an_value = 0;

    if ( airquality_read_an_pin_value ( &airquality, &airquality_an_value ) != ADC_ERROR ) {
        log_printf( &logger, " ADC Value : %u\r\n", airquality_an_value );
    }

    float airquality_an_voltage = 0;

    if ( airquality_read_an_pin_voltage ( &airquality, &airquality_an_voltage ) != ADC_ERROR ) {
        log_printf( &logger, " AN Voltage : %.3f[V]\r\n\n", airquality_an_voltage );
    }

    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.Airquality

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.