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.
- ESP32 development board
- MAX30100 Pulse Oximeter and Heart Rate Sensor module
- Jumper wires
- Breadboard (optional)
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.
- 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).
- 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.
- Go to Sketch > Include Library > Manage Libraries.
- Search for MAX30100 by oxullo.
- Click Install.
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();
}
}