ESP32 with MAX30100 (Pulse Oximeter and Heart Rate Sensor)

This project demonstrates how to interface an ESP32 microcontroller with the MAX30100 sensor to measure heart rate and blood oxygen saturation (SpO2). The MAX30100 integrates a pulse oximeter and a heart rate monitor and communicates with the ESP32 via I2C.

Hardware Requirements

ESP32 development board
MAX30100 Pulse Oximeter and Heart Rate Sensor module
Jumper wires
Breadboard (optional)

Wiring

Connect the MAX30100 to the ESP32 using the following connections:

MAX30100 Pin	ESP32 Pin	Description
VCC	3.3V or 5V	Power supply
GND	GND	Ground
SCL	GPIO 22	I2C Clock (SCL)
SDA	GPIO 21	I2C Data (SDA)
INT	Optional	Interrupt (optional)

Note: The MAX30100 module should work with both 3.3V and 5V depending on the specific model. Check your sensor module specifications before connecting power.

Software Requirements

Arduino IDE with ESP32 board support (Follow this guide to install ESP32 in the Arduino IDE).
MAX30100 library by oxullo (can be installed via Arduino Library Manager).

Installation

1. Install the ESP32 Board Support

Open Arduino IDE.
Go to File > Preferences.

In the "Additional Boards Manager URLs" field, add:

https://dl.espressif.com/dl/package_esp32_index.json

Go to Tools > Board > Boards Manager, search for "ESP32" and install the ESP32 board package.

2. Install the MAX30100 Library

Go to Sketch > Include Library > Manage Libraries.
Search for MAX30100 by oxullo.
Click Install.

3. Code Example

Use the following code to interface with the MAX30100 sensor and display heart rate and SpO2 readings on the serial monitor.

#include <Wire.h>
#include "MAX30100_PulseOximeter.h"

// Define the I2C pins (default GPIO 21 for SDA and GPIO 22 for SCL)
#define REPORTING_PERIOD_MS     1000

PulseOximeter pox;
uint32_t tsLastReport = 0;

// Callback routine for when a pulse is detected
void onPulseDetected()
{
    Serial.println("Pulse detected!");
}

void setup()
{
    Serial.begin(115200);

    // Initialize I2C communication
    Wire.begin(21, 22);

    Serial.print("Initializing Pulse Oximeter...");

    // Initialize the Pulse Oximeter
    if (!pox.begin()) {
        Serial.println("FAILED");
        for(;;);
    } else {
        Serial.println("SUCCESS");
    }

    // Set the callback for when a pulse is detected
    pox.setOnBeatDetectedCallback(onPulseDetected);
}

void loop()
{
    // Update the sensor readings
    pox.update();

    // Report the heart rate and SpO2 readings every second
    if (millis() - tsLastReport > REPORTING_PERIOD_MS) {
        Serial.print("Heart rate:");
        Serial.print(pox.getHeartRate());
        Serial.print(" bpm / SpO2:");
        Serial.print(pox.getSpO2());
        Serial.println(" %");

        tsLastReport = millis();
    }
}