Heart Rate 2 Click

Heart Rate 2 Click is an add-on board based on MAXM86161 from Maxim Integrated a complete, integrated, optical data acquisition system, ideal for optical pulse oximetry and heart-rate detection applications. The optical readout has a low-noise signal conditioning analog front-end (AFE), including 19-bit ADC, an industry-lead ambient light cancellation (ALC) circuit, and a picket fence detect and replace algorithm.

Click Product page

Click library

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

Software Support

We provide a library for the HeartRate2 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 HeartRate2 Click driver.

Standard key functions :

• Config Object Initialization function.

  void heartrate2_cfg_setup ( heartrate2_cfg_t *cfg );

• Initialization function.

  HEARTRATE2_RETVAL heartrate2_init ( heartrate2_t ctx, heartrate2_cfg_t cfg );

• Click Default Configuration function.

  void heartrate2_default_cfg ( heartrate2_t *ctx );

Example key functions :

• This function settings en pin status.

  void heartrate2_set_en ( heartrate2_t *ctx, uint8_t state );

• This function restarts device.

  void heartrate2_soft_reset ( heartrate2_t *ctx );

• This function reads data buffer from the desired register.

  void heartrate2_read_fifo ( heartrate2_t ctx, heartrate2_fifo_data_t fifo );

Examples Description

This example demonstrates the use of Heart rate 2 Click board.

The demo application is composed of two sections :

Application Init

Initilizes the driver, resets the device, checks the device ID and applies default settings.

void application_init ( void )
{
    log_cfg_t log_cfg;
    heartrate2_cfg_t cfg;
    uint8_t rd_stat;

    /** 
     * 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.

    heartrate2_cfg_setup( &cfg );
    HEARTRATE2_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    heartrate2_init( &heartrate2, &cfg );

    log_printf( &logger, "Configuring the module...\r\n" );
    Delay_ms ( 1000 );

    heartrate2_set_en( &heartrate2, HEARTRATE2_PIN_HIGH );
    Delay_ms ( 100 );
    heartrate2_soft_reset ( &heartrate2 );

    rd_stat = heartrate2_generic_read( &heartrate2, HEARTRATE2_REG_PART_ID );

    if ( rd_stat != HEARTRATE2_DEV_ID )
    {
        log_error( &logger, "---- WRONG ID ----" );
        log_printf( &logger, "Please restart your system.\r\n" );
        for ( ; ; );
    }

    heartrate2_default_cfg( &heartrate2, HEARTRATE2_CONFIG_GREEN );
    log_printf( &logger, "The module has been configured!\r\n" );
    Delay_ms ( 1000 );
}

Application Task

Reads the data from Green diode and displays the results on USB UART if the measured data is above defined threshold, otherwise, it displays a desired message on the terminal.

void application_task ( void )
{
    heartrate2_fifo_data_t fifo_object;

    heartrate2_read_fifo( &heartrate2, &fifo_object );

    if ( fifo_object.tag == HEARTRATE2_FIFO_TAG_PPG1_LEDC1 )
    {
        counter++;
        if ( fifo_object.data_val > 1000 )
        {
            log_printf( &logger, "%lu;\r\n", fifo_object.data_val );
            counter = 1000;
        }
        else if ( counter > 1000 )
        {
            log_printf( &logger, "Please place your index finger on the sensor.\r\n" );
            counter = 0;
        }
    }
}  

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.HeartRate2

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.