Intermediate
30 min
0

Monitor your heart's health with MAX30101 and STM32F437ZG

Keep your heart on track

Heart rate 4 Click with UNI Clicker

Published Jul 28, 2023

Click board™

Heart rate 4 Click

Development board

UNI Clicker

Compiler

NECTO Studio

MCU

STM32F437ZG

Stay in tune with your heart's needs and elevate your well-being with our cutting-edge heart rate monitoring technology

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Hardware Overview

How does it work?

Heart Rate 4 Click is based on the MAX30101 high-sensitivity pulse oximeter and heart-rate sensor from Analog Devices. The click is designed to run on either 3.3V or 5V power supply. It communicates with the target MCU over the I2C interface, with additional functionality provided by the INT pin on the mikroBUS™ line. The MAX30101 is an integrated pulse oximetry and heart-rate monitor module. It includes internal LEDs, photodetectors, optical elements, and low-noise electronics with ambient light rejection. The MAX30101 integrates red, green, and IR

(infrared) LED drivers to modulate LED pulses for SpO2 and HR measurements. The LED current can be programmed from 0 to 50mA with proper supply voltage. The device includes a proximity function to save power and reduce visible light emission when the user's finger is not on the sensor. The MAX30101 has an on-chip temperature sensor for calibrating the temperature dependence of the SpO2 subsystem. The temperature sensor has an inherent resolution of 0.0625°C. Oxygen-saturated blood absorbs light differently than unsaturated blood. Pulse

oximeters measure the oxygen saturation in one's blood. Or, more precisely, the percentage of hemoglobin molecules in blood saturated with oxygen. These readings go from 94% to 100% in a healthy adult. Since oxygen-saturated blood absorbs more infrared light than red light, and unsaturated blood absorbs more red light than infrared light, the SpO2 readings are calculated by comparing the amount of these two types of light. It is best to use your finger for measurement.

Heart rate 4 Click top side image
Heart rate 4 Click bottom side image

Features overview

Development board

UNI Clicker is a compact development board designed as a complete solution that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It supports a wide range of microcontrollers, such as different ARM, PIC32, dsPIC, PIC, and AVR from various vendors like Microchip, ST, NXP, and TI (regardless of their number of pins), four mikroBUS™ sockets for Click board™ connectivity, a USB connector, LED indicators, buttons, a debugger/programmer connector, and two 26-pin headers for interfacing with external electronics. Thanks to innovative manufacturing technology, it allows you to build

gadgets with unique functionalities and features quickly. Each part of the UNI Clicker development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the UNI Clicker programming method, using a third-party programmer or CODEGRIP/mikroProg connected to onboard JTAG/SWD header, the UNI Clicker board also includes a clean and regulated power supply module for the development kit. It provides two ways of board-powering; through the USB Type-C (USB-C) connector, where onboard voltage regulators provide the appropriate voltage levels to each component on the board, or using a Li-Po/Li

Ion battery via an onboard battery connector. All communication methods that mikroBUS™ itself supports are on this board (plus USB HOST/DEVICE), including the well-established mikroBUS™ socket, a standardized socket for the MCU card (SiBRAIN standard), and several user-configurable buttons and LED indicators. UNI Clicker is an integral part of the Mikroe ecosystem, allowing you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

UNI clicker double image

Microcontroller Overview

MCU Card / MCU

default

Type

8th Generation

Architecture

ARM Cortex-M4

MCU Memory (KB)

1024

Silicon Vendor

STMicroelectronics

Pin count

144

RAM (Bytes)

262144

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
Interrupt
PD3
INT
NC
NC
TX
NC
NC
RX
I2C Clock
PB8
SCL
I2C Data
PB9
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

Heart rate 4 Click Schematic schematic

Step by step

Project assembly

UNI Clicker front image hardware assembly

Start by selecting your development board and Click board™. Begin with the UNI Clicker as your development board.

UNI Clicker front image hardware assembly
Thermo 28 Click front image hardware assembly
SiBRAIN for STM32F745VG front image hardware assembly
Prog-cut hardware assembly
UNI Clicker MB 1 - upright/with-background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
Necto image step 5 hardware assembly
Necto image step 6 hardware assembly
Necto image step 7 hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Debug Image Necto Step hardware assembly

Track your results in real time

Application Output

After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.

Application Output Step 1

After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.

Application Output Step 3

Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.

Application Output Step 4

Software Support

Library Description

This library contains API for Heart Rate 4 Click driver.

Key functions:

  • heartrate4_get_intrrupt - Function is used to read desired interrupt specified by flag

  • heartrate4_get_red_val - Function is used to read the oldest RED value

  • heartrate4_enable_slot - Function is used to determine which LED is active in each time slot

Open Source

Code example

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

/*!
 * \file 
 * \brief HeartRate4 Click example
 * 
 * # Description
 * This example demonstrates the use of Heart rate 4 click board.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initalizes I2C driver, applies default settings, and makes an initial log.
 * 
 * ## Application Task  
 * Reads data from Red diode and displays the results on USB UART if the measured data
 * is above defined threshold, otherwise, it displays desired message on the terminal.
 *
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "heartrate4.h"

// ------------------------------------------------------------------ VARIABLES

static heartrate4_t heartrate4;
static log_t logger;

static uint32_t red_samp = 0;
static uint8_t counter = 200;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    heartrate4_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.

    heartrate4_cfg_setup( &cfg );
    HEARTRATE4_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    heartrate4_init( &heartrate4, &cfg );

    Delay_ms( 100 );
    heartrate4_default_cfg( &heartrate4 );
    Delay_ms( 100 );
}

void application_task ( void )
{
    if ( heartrate4_get_intrrupt( &heartrate4, 1 ) & 0x40 )
    {
        red_samp = heartrate4_get_red_val( &heartrate4 );
        counter++;
        
        // If sample pulse amplitude is not under threshold value 0x8000
        if ( red_samp > 0x8000 )
        {
            log_printf( &logger, "%lu\r\n", red_samp );
            Delay_ms( 1 );
            counter = 200;
        }
        else if ( counter > 200 )
        {
            log_printf( &logger, "Place Finger On Sensor\r\n" );
            Delay_ms( 100 );
            counter = 0;
        }
    }
}

void main ( void )
{
    application_init( );

    for ( ; ; )
    {
        application_task( );
    }
}


// ------------------------------------------------------------------------ END

Additional Support

Resources