Heart Rate Click

Heart Rate Click is a heart rate monitoring and pulse oximetry measuring Click board™. It features an advanced oximeter and heart rate monitoring sensor, which relies on two integrated LEDs, a photosensitive element, and a very accurate and advanced low noise analog front end, to provide clean and accurate readings.

Click Product page

Click library

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

Software Support

We provide a library for the HeartRate 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 HeartRate Click driver.

Standard key functions :

• Config Object Initialization function.

  void heartrate_cfg_setup ( heartrate_cfg_t *cfg );

• Initialization function.

  HEARTRATE_RETVAL heartrate_init ( heartrate_t ctx, heartrate_cfg_t cfg );

• Click Default Configuration function.

  void heartrate_default_cfg ( heartrate_t *ctx );

Example key functions :

• Using this function we can check if the data is ready for reading

  uint8_t heartrate_data_ready ( heartrate_t *ctx );

• Using this function we can read IR and RED values.

  uint8_t heartrate_read_ir_red ( heartrate_t ctx, uint16_t ir_buff, uint16_t *red_buff );

• This function reads data from the desired register.

  void heartrate_generic_read ( heartrate_t ctx, uint8_t reg, uint16_t len, uint8_t data_buf );

Examples Description

This Click features an advanced oximeter and heart rate monitoring sensor, which relies on two integrated LEDs. It is enough to place an index finger on a top of the sensor to get both of the heart rate and blood oxygen saturation via the I2C interface.

The demo application is composed of two sections :

Application Init

Initializes heartrate driver and set the Click board default configuration.

void application_init ( void )
{
    log_cfg_t log_cfg;
    heartrate_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.

    heartrate_cfg_setup( &cfg );
    HEARTRATE_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    heartrate_init( &heartrate, &cfg );

    heartrate_default_cfg( &heartrate );
    Delay_ms ( 100 );
}

Application Task

Reading values from both Ir and Red diode and displaying their average values on the USB UART.

void application_task ( void )
{
    if ( heartrate_data_ready( &heartrate ) )      
    {
        sample_num = heartrate_read_ir_red( &heartrate, ir_buff, red_buff );             
        if ( sample_num > 0 )
        {
            ir_average = 0;
            red_average = 0;
            for ( uint8_t cnt = 0; cnt < sample_num; cnt++ )
            {              
                ir_average += ir_buff[ cnt ];
                red_average += red_buff[ cnt ];
            }                 
            ir_average  /= sample_num;
            red_average /= sample_num;
            counter++;
            if( red_average > 100 && ir_average > 100 )                
            {       
                log_printf( &logger, "%lu;%lu;\r\n", red_average, ir_average );
                counter = 500;
            }
            else
            {
                if ( counter > 500 ) 
                {
                    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.HeartRate

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.