Build A Heart Rate Spo2 Monitor Esp32 Gy-max3010

#include <Arduino.h>
// Heart Rate & SpO2 Monitor
// ESP32-S3 + MAX30102
// I2C on GPIO8 (SDA), GPIO9 (SCL)

#include <Wire.h>
#include <MAX30105.h>
#include <heartRate.h>
#include <spo2_algorithm.h>

// Pin definitions
#define I2C_SDA 8
#define I2C_SCL 9
#define MAX30102_INT_PIN 1

// Reporting period for serial update
#define REPORTING_PERIOD_MS 1000

// Objects
MAX30105 particleSensor;

// Heart rate averaging
#define RATE_SIZE 4
byte rates[RATE_SIZE];
byte rateSpot = 0;
long lastBeat = 0;
float beatsPerMinute = 0;
int beatAvg = 0;

// SpO2 calculation buffers (kept small for memory)
#define SPO2_BUFFER_SIZE 50
uint32_t irBuffer[SPO2_BUFFER_SIZE];
uint32_t redBuffer[SPO2_BUFFER_SIZE];
int32_t spo2Value = 0;
int8_t spo2Valid = 0;
int32_t heartRateValue = 0;
int8_t heartRateValid = 0;

// State
uint32_t lastReportTime = 0;
float lastBPM = 0.0;
int lastSpO2 = 0;
bool sensorReady = false;
uint32_t lastSpO2Calc = 0;
#define SPO2_CALC_INTERVAL_MS 5000

// Finger detection threshold
#define FINGER_THRESHOLD 50000

void setup() {
    Serial.begin(115200);
    delay(500);
    Serial.println(F("Heart Rate & SpO2 Monitor starting..."));

    // Initialize I2C with custom pins for ESP32-S3
    Wire.begin(I2C_SDA, I2C_SCL);

    // Configure interrupt pin
    pinMode(MAX30102_INT_PIN, INPUT_PULLUP);

    // Initialize MAX30102
    Serial.println(F("Initializing MAX30102..."));
    if (!particleSensor.begin(Wire, I2C_SPEED_FAST)) {
        Serial.println(F("MAX30102 init FAILED! Check wiring."));
        sensorReady = false;
    } else {
        Serial.println(F("MAX30102 init SUCCESS"));
        sensorReady = true;

        // Configure sensor for SpO2 + HR
        byte ledBrightness = 0x1F; // ~6.4mA
        byte sampleAverage = 4;
        byte ledMode = 2;         // Red + IR
        int sampleRate = 200;
        int pulseWidth = 411;
        int adcRange = 4096;

        particleSensor.setup(ledBrightness, sampleAverage, ledMode,
                             sampleRate, pulseWidth, adcRange);

        // Enable FIFO rolling
        particleSensor.enableAFULL();
    }

    lastReportTime = millis();
    lastSpO2Calc = millis();
}

void loop() {
    if (!sensorReady) {
        // Retry sensor init every 5 seconds
        static uint32_t lastRetry = 0;
        if (millis() - lastRetry > 5000) {
            Serial.println(F("Retrying MAX30102 init..."));
            if (particleSensor.begin(Wire, I2C_SPEED_FAST)) {
                Serial.println(F("MAX30102 init SUCCESS on retry"));
                sensorReady = true;
                particleSensor.setup(0x1F, 4, 2, 200, 411, 4096);
                particleSensor.enableAFULL();
            }
            lastRetry = millis();
        }
        return;
    }

    // Read IR value for heart rate detection
    long irValue = particleSensor.getIR();

    // Check if finger is on sensor
    if (irValue > FINGER_THRESHOLD) {
        // Check for beat
        if (checkForBeat(irValue)) {
            long delta = millis() - lastBeat;
            lastBeat = millis();

            beatsPerMinute = 60.0 / (delta / 1000.0);

            if (beatsPerMinute > 20 && beatsPerMinute < 255) {
                rates[rateSpot++ % RATE_SIZE] = (byte)beatsPerMinute;

                // Compute average
                beatAvg = 0;
                byte count = min((byte)(rateSpot), (byte)RATE_SIZE);
                for (byte x = 0; x < count; x++) {
                    beatAvg += rates[x];
                }
                beatAvg /= count;
            }
        }

        // Periodically compute SpO2
        if (millis() - lastSpO2Calc > SPO2_CALC_INTERVAL_MS) {
            lastSpO2Calc = millis();

            // Collect samples for SpO2 calculation
            for (int i = 0; i < SPO2_BUFFER_SIZE; i++) {
                while (!particleSensor.available())
                    particleSensor.check();

                redBuffer[i] = particleSensor.getRed();
                irBuffer[i] = particleSensor.getIR();
                particleSensor.nextSample();
            }

            // Calculate SpO2
            maxim_heart_rate_and_oxygen_saturation(
                irBuffer, SPO2_BUFFER_SIZE, redBuffer,
                &spo2Value, &spo2Valid,
                &heartRateValue, &heartRateValid);

            if (spo2Valid && spo2Value > 0 && spo2Value <= 100) {
                lastSpO2 = spo2Value;
            }
        }

        lastBPM = beatAvg;
    } else {
        // No finger detected
        lastBPM = 0;
        lastSpO2 = 0;
        beatAvg = 0;
        rateSpot = 0;
    }

    // Report to serial periodically
    if (millis() - lastReportTime > REPORTING_PERIOD_MS) {
        if (irValue > FINGER_THRESHOLD) {
            Serial.print(F("BPM: "));
            Serial.print(lastBPM, 1);
            Serial.print(F("  Avg BPM: "));
            Serial.print(beatAvg);
            Serial.print(F("  SpO2: "));
            Serial.print(lastSpO2);
            Serial.print(F("%  IR: "));
            Serial.println(irValue);
        } else {
            Serial.println(F("No finger detected. Place finger on sensor."));
        }
        lastReportTime = millis();
    }
}