#include <LiquidCrystal_I2C.h>

#define lcdAddress 0x27
#define lcdColumn 20
#define lcdRows 4
LiquidCrystal_I2C lcd(lcdAddress,lcdColumn,lcdRows);

#define greenLedPin 26
#define redLedPin 27
#define  pulsePin 17
int minHeartRate = 60;
int maxHeartRate = 100;
void setup() {
  // put your setup code here, to run once:
  lcd.init();
  lcd.backlight();
  pinMode(greenLedPin, OUTPUT);
  pinMode(redLedPin, OUTPUT);
  //pinMode(pulsePin, INPUT);

}
void heartRateCalculation(int pulseValue){
 
}
void loop() {
   int pulseValue = analogRead(pulsePin);
  
  // Convert pulseValue to voltage
  float voltage = pulseValue * (5 / 1023.0);
  
  // calculate heartRate from voltage
  int heartRate = (voltage / 3.3) * 675;
  if (heartRate  >= minHeartRate && heartRate <= maxHeartRate){
    lcd.clear();
    lcd.setCursor(1, 0);
    lcd.print("HR monitor");
    lcd.setCursor(2,2);
    lcd.print("Heart rate: ");
    lcd.println(heartRate);
    delay(100);
    digitalWrite(greenLedPin, HIGH);
    delay(50);
    digitalWrite(greenLedPin, LOW);
  }
  else{
    
    lcd.clear();
    lcd.setCursor(1, 0);
    lcd.print("Heart rate monitor");
    lcd.setCursor(0, 1);
    lcd.print("Heart rate Abnormal ");
    lcd.setCursor(2, 2);
    lcd.print("Heart rate: ");
    lcd.println(heartRate); 
    delay(100);
    digitalWrite(redLedPin, HIGH);
    delay(50);
    digitalWrite(redLedPin, LOW);

  }
}