MAX10302 on a MEGA

I have a been developing a pulse oximeter using pins A4 and A5 on an arduino uno and it has been working well. i am now moving the project to a Mega and i can not get the MAX10302 working. any ideas or information would be very helpful. i am new to arduino so sorry for any stupidity within my code.

  Optical SP02 Detection (SPK Algorithm) using the MAX30105 Breakout
  By: Nathan Seidle @ SparkFun Electronics
  Date: October 19th, 2016

  This demo shows heart rate and SPO2 levels.

  It is best to attach the sensor to your finger using a rubber band or other tightening
  device. Humans are generally bad at applying constant pressure to a thing. When you
  press your finger against the sensor it varies enough to cause the blood in your
  finger to flow differently which causes the sensor readings to go wonky.

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

MAX30105 particleSensor;

#define MAX_BRIGHTNESS 255

#if defined(__AVR_ATmega328P__) || defined(__AVR_ATmega168__)
//Arduino Uno doesn't have enough SRAM to store 100 samples of IR led data and red led data in 32-bit format
//To solve this problem, 16-bit MSB of the sampled data will be truncated. Samples become 16-bit data.
uint16_t irBuffer[100]; //infrared LED sensor data
uint16_t redBuffer[100];  //red LED sensor data
uint32_t irBuffer[100]; //infrared LED sensor data
uint32_t redBuffer[100];  //red LED sensor data

int32_t bufferLength; //data length
int32_t spo2; //SPO2 value
int8_t validSPO2; //indicator to show if the SPO2 calculation is valid
int32_t heartRate; //heart rate value
int8_t validHeartRate; //indicator to show if the heart rate calculation is valid

int pulseLED = 11; //Must be on PWM pin
int readLED = 13; //Blinks with each data read
int pass;
int count;

void setup()
  static int count = 0;
  Serial.begin(115200); // initialize serial communication at 115200 bits per second:

  pinMode(pulseLED, OUTPUT);
  pinMode(readLED, OUTPUT);

  // Initialize sensor
  if (!particleSensor.begin(Wire, I2C_SPEED_FAST)) //Use default I2C port, 400kHz speed
    Serial.println(F("MAX30105 was not found. Please check wiring/power."));
    while (1);

  int ledBrightness = 60; //Options: 0=Off to 255=50mA
  int sampleAverage = 4; //Options: 1, 2, 4, 8, 16, 32
  int ledMode = 3; //Options: 1 = Red only, 2 = Red + IR, 3 = Red + IR + Green
  int sampleRate = 100 ; //Options: 50, 100, 200, 400, 800, 1600, 3200,
  int pulseWidth = 411; //Options: 69, 118, 215, 411
  int adcRange = 4096; //Options: 2048, 4096, 8192, 16384

  particleSensor.setup(ledBrightness, sampleAverage, ledMode, sampleRate, pulseWidth, adcRange); //Configure sensor with these settings

  bufferLength = 100; //buffer length of 100 stores 4 seconds of samples running at 25sps
  for (int32_t spo2 = -999; spo2 < 100 && 95 < spo2 ; spo2++); //smooting average for spo2
  //calculate heart rate and SpO2 after first 100 samples (first 4 seconds of samples)
  maxim_heart_rate_and_oxygen_saturation(irBuffer, bufferLength, redBuffer, &spo2, &validSPO2, &heartRate, &validHeartRate);

  //Continuously taking samples from MAX30102. SpO2 are calculated every 1 second

  for (int c = 0; c < 7; c++)
    int count = count + 1;
    for (int i = 25; i < 100; i++)
      redBuffer[i - 25] = redBuffer[i];
      irBuffer[i - 25] = irBuffer[i];

    //take 25 sets of samples before calculating the heart rate.
    for (int i = 75; i < 100; i++)
      while (particleSensor.available() == false) //do we have new data?
        particleSensor.check(); //Check the sensor for new data

      //digitalWrite(readLED, !digitalRead(readLED)); //Blink onboard LED with every data read

      redBuffer[i] = particleSensor.getRed();
      irBuffer[i] = particleSensor.getIR();
      particleSensor.nextSample(); //We're finished with this sample so move to next sample
      if (spo2 >= 90) {
        Serial.print(F(", Pass/Fail="));
        int pass = 1;
      else {
        Serial.print(F(", Pass/Fail="));
        int pass = 0;


      Serial.print(F(", SPO2="));
      Serial.print(spo2, DEC);

      Serial.print(F(", SPO2Valid="));
      Serial.println(validSPO2, DEC);

    maxim_heart_rate_and_oxygen_saturation(irBuffer, bufferLength, redBuffer, &spo2, &validSPO2, &heartRate, &validHeartRate);

void loop()


You need to explain what you expected to happen, and what happens instead.

nevermind just figured it out had to change the pins that where being called from a4 and a5 to 20 and 21. it is working now but the values are off. it is currently reading out SPo2 of 27-29 when it was reading 97 to 99 on the uno.

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