pH 2 Click

pH 2 Click is a compact add-on board used to determine the alkalinity or acidity of a sample. This board features the MCP607, a low-bias current Op Amp from Microchip, performing level shifting and high-input impedance buffering in a single-supply pH-electrode circuit.

Click Product page

Click library

• Author : Stefan Ilic
• Date : Jan 2023.
• Type : ADC/I2C type

Software Support

We provide a library for the pH 2 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 pH 2 Click driver.

Standard key functions :

• ph2_cfg_setup Config Object Initialization function.

  void ph2_cfg_setup ( ph2_cfg_t *cfg );

• ph2_init Initialization function.

  err_t ph2_init ( ph2_t *ctx, ph2_cfg_t *cfg );

Example key functions :

• ph2_calibrate Ph 2 calibrate function.

  err_t ph2_calibrate ( ph2_t *ctx, float pH_value );

• ph2_calculate_ph Ph 2 calculate pH value function.

  err_t ph2_calculate_ph ( ph2_t *ctx, float *pH_value );

• ph2_calibrate_offset Ph 2 calibrate offset function.

  void ph2_calibrate_offset ( ph2_t *ctx );

Example Description

This library contains API for pH 2 Click driver. The library initializes and defines the I2C bus drivers or ADC drivers to read data from pH probe.

The demo application is composed of two sections :

Application Init

Initializes the driver and performs offset calibration, as well as calibration in pH-neutral substance.

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    ph2_cfg_t ph2_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.
    ph2_cfg_setup( &ph2_cfg );
    PH2_MAP_MIKROBUS( ph2_cfg, MIKROBUS_1 );
    err_t init_flag = ph2_init( &ph2, &ph2_cfg );
    if ( ( ADC_ERROR == init_flag ) || ( I2C_MASTER_ERROR == init_flag ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }

    log_printf( &logger, " ================================ \r\n" );
    log_printf( &logger, "     Performing calibration       \r\n" );
    log_printf( &logger, " ================================ \r\n" );
    log_printf( &logger, " Disconect BNC connector, \r\n" );
    log_printf( &logger, "    short-circuit it, \r\n" );
    log_printf( &logger, " adjust offset potentiometer \r\n" );
    log_printf( &logger, " ================================ \r\n" );
    log_printf( &logger, " STAT1 - turn clockwise \r\n" );
    log_printf( &logger, " STAT2 - turn counter-clockwise \r\n" );
    log_printf( &logger, " ================================ \r\n" );

    ph2_calibrate_offset( &ph2 );

    log_printf( &logger, " Calibration completed \r\n" );
    log_printf( &logger, " ================================ \r\n" );

    log_printf( &logger, " Connect probe back \r\n" );
    log_printf( &logger, " ================================ \r\n" );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    log_printf( &logger, "  Place probe into pH  \r\n" );
    log_printf( &logger, " neutral substance for \r\n" );
    log_printf( &logger, " mid point calibration \r\n" );
    log_printf( &logger, " ================================ \r\n" );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    log_printf( &logger, " Starting calibration  \r\n" );
    log_printf( &logger, " ================================ \r\n" );  

    ph2_calibrate( &ph2, 7 );

    log_printf( &logger, " Calibration done!  \r\n" );
    log_printf( &logger, " ================================ \r\n" ); 

    log_info( &logger, " Application Task " );
    log_printf( &logger, " ================================ \r\n" ); 
}

Application Task

This example demonstrates the use of the pH 2 Click board by reading pH value of the substance where probe is placed.

void application_task ( void ) 
{
    float pH_val = 0;
    ph2_calculate_ph( &ph2, &pH_val );
    log_printf( &logger, " pH value: %.3f \r\n", pH_val );
    log_printf( &logger, " ================================ \r\n" ); 
    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.pH2

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.