Heart Beat Sleep Sensor

#include "Particle.h"


SYSTEM_MODE(AUTOMATIC);
#include "Particle.h"


SYSTEM_MODE(AUTOMATIC);

SerialLogHandler logHandler(LOG_LEVEL_INFO);

int heartPin = 6;
int analogPin = A5;
int led = 7;
int sensor;
int lastSample;
int beats = 0;
unsigned long minuteStart = 0;
int highestNum = 0;
int lowestNum = 4000;
int threshHold;
bool readingStart = true;
unsigned long time2;
unsigned long timePassed1 = 10000;
unsigned long timePassed2 = 10000;
int countDownLength = 10;
double beats10Sec;
int cycleTimes = 1;


void setup() {
    pinMode(led, OUTPUT);
    pinMode(heartPin, OUTPUT);
    Serial.begin(9600);
    digitalWrite(heartPin, HIGH);
}

void loop() {
    if(countDownLength > 0){
        Serial.print("Count Down: ");
        Serial.println(countDownLength);
        countDownLength -= 1;
        delay(1000);
        minuteStart = millis();
    }
    else {
        time2 = millis();
        sensor = analogRead(analogPin);
        //Serial.println(sensor);
        if(time2-minuteStart<timePassed2){
            if(sensor>highestNum && sensor<3400){
                highestNum = sensor;
            }
            if(sensor<lowestNum && sensor>1300){
                lowestNum = sensor;
            }
        }
        else{
            if (readingStart){
                Serial.println("Calibration Ended");
                Serial.println("Reading Started");
                readingStart = false;        
            }
            threshHold = (lowestNum+highestNum)/2;
            if(sensor >= threshHold && lastSample < threshHold){
                digitalWrite(led, HIGH);
                //Serial.println(sensor);
                beats++;
            }else if(sensor < threshHold && lastSample > threshHold){
                digitalWrite(led, LOW);
                //Serial.println(sensor);
            }
            lastSample = sensor;
            if (time2-minuteStart > timePassed1*cycleTimes+timePassed2){
                beats10Sec = (double)beats*(6.0/cycleTimes);
                cycleTimes ++;
                Serial.print("BPM: ");
                Serial.println(beats10Sec);
                if(beats10Sec>40 && beats10Sec<60){
                    Serial.println("Good Sleep");
                }else{
                    Serial.println("Bad Sleep");
                }
                if(time2 - minuteStart >= timePassed2 + 60000){
                    //Serial.print(" BPM: ");
                    //Serial.println(beats);
                    beats = 0;
                    minuteStart = time2;
                    Serial.println("Reading ended");
                    readingStart = true;
                    cycleTimes = 1;
                }
            }
        }
        delay(100);
    }
}