MAX30102 Pulse Oximeter with an ESP32 DevKit V1

// MAX30102 Pulse Oximeter on ESP32 DevKit V1: wiring and a free simulation at https://www.tinkered.ai/components/max30102/esp32
#include <Wire.h>
#include "MAX30105.h"
#include "heartRate.h"

MAX30105 sensor;
const byte RATE_SIZE = 4;
byte rates[RATE_SIZE];
byte rateSpot = 0;
long lastBeat = 0;
float beatsPerMinute = 0;
int beatAvg = 0;

void setup() {
  Serial.begin(115200);
  if (!sensor.begin(Wire, I2C_SPEED_FAST)) {
    Serial.println("MAX30102 not found");
    while (1) delay(10);
  }
  sensor.setup();                     // 6.4 mA LEDs, 4 averaged at 400 sps, 411 us, 4096 nA
  sensor.setPulseAmplitudeRed(0x0A);  // red dimmed: heart rate uses the IR channel
  sensor.setPulseAmplitudeGreen(0);
}

void loop() {
  long ir = sensor.getIR();
  if (checkForBeat(ir)) {
    long delta = millis() - lastBeat;
    lastBeat = millis();
    beatsPerMinute = 60 / (delta / 1000.0);
    if (beatsPerMinute < 255 && beatsPerMinute > 20) {
      rates[rateSpot++] = (byte)beatsPerMinute;
      rateSpot %= RATE_SIZE;
      beatAvg = 0;
      for (byte x = 0; x < RATE_SIZE; x++) beatAvg += rates[x];
      beatAvg /= RATE_SIZE;
    }
  }
  Serial.print("IR=");
  Serial.print(ir);
  Serial.print(" BPM=");
  Serial.print(beatsPerMinute);
  Serial.print(" Avg=");
  Serial.print(beatAvg);
  if (ir < 50000) Serial.print(" (no finger)");
  Serial.println();
}