#include <Wire.h> 
#include <DHT.h>
#include <PubSubClient.h>
#include <Arduino.h>
#include <LiquidCrystal_I2C.h>

#define lcd_ADDR 0x27
#define lcd_COLUMNS 16
#define lcd_ROWS 2

LiquidCrystal_I2C lcd(lcd_ADDR, lcd_COLUMNS, lcd_ROWS);

#define PULSE_PIN 35
#define redLEDPin 12
#define greenLEDPin 14

int minHeartRate = 60;
int maxHeartRate = 100;

void setup() {
  lcd.init();
  lcd.backlight();
  Wire.begin(23, 22);
  Serial.begin(115200);
  lcd.print("Heart Monitor");
  pinMode(redLEDPin, OUTPUT);
  pinMode(greenLEDPin, OUTPUT);
}

void loop() {
  // Read pulseValue from PULSE_PIN 
  int16_t pulseValue = analogRead(PULSE_PIN);
  
  // Convert pulseValue to voltage
  float voltage = pulseValue * (5 / 4095.0);
  
  // calculate heartRate from voltage
  int heartRate = (voltage / 3.3) * 675;

  
  if (heartRate < minHeartRate){
    lcd.clear();
    lcd.print("Heart rate below ");
    lcd.setCursor(0, 1);
    lcd.print("minimum: ");
    lcd.println(heartRate);
    lcd.setCursor(13,1);
    lcd.print("b/m");
    digitalWrite(redLEDPin, HIGH); // Turn on LED
    delay(20); // Wait for half of the blink interval
    digitalWrite(redLEDPin, LOW); // Turn off LED
    delay(20); // Wait for the other half of the blink interval

  }
  else if (heartRate > maxHeartRate){
    lcd.clear();
    lcd.print("Heart rate above ");
    lcd.setCursor(0, 1);
    lcd.print("maximum: ");
    lcd.println(heartRate);
    lcd.setCursor(13,1);
    lcd.print("b/m");
    digitalWrite(redLEDPin, HIGH); // Turn on LED
    delay(20); // Wait for half of the blink interval
    digitalWrite(redLEDPin, LOW); // Turn off LED
    delay(20); // Wait for the other half of the blink interval

    
  }else{
    lcd.clear();
    
    lcd.println("Heart Monitor");
    lcd.setCursor(0, 1);
    lcd.print("Heart rate:");
    lcd.println(heartRate);
     lcd.setCursor(13,1);
    lcd.println("b/m");
    digitalWrite(greenLEDPin, HIGH); // Turn on LED
    delay(100); // Wait for half of the blink interval
    digitalWrite(greenLEDPin, LOW); // Turn off LED
    delay(100); // Wait for the other half of the blink interval

  }
  

  delay(1000); 
}