//=================================================================
//                  INIT
//=================================================================
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16,2); //

const int LED_RED=10;
const int LED_GREEN=11;
const int RELAY=12;

//buttons for up and down
const int up_key=3;
const int down_key=2;

int SetPoint=28;
int heater = 0;

unsigned long previousMillis = 0;
const long interval = 300000;  // 5 minutes
//=================================================================
//                  SETUP
//=================================================================
void setup(){
  Serial.begin(9600);
  //Serial.print("boot \n");
  pinMode(LED_RED,OUTPUT);
  pinMode(LED_GREEN,OUTPUT);
  pinMode(RELAY,OUTPUT);
  pinMode(up_key,INPUT);
  pinMode(down_key,INPUT);

  digitalWrite(up_key,HIGH);
  digitalWrite(down_key,HIGH);

  lcd.init();
  lcd.backlight();

  digitalWrite(LED_GREEN,HIGH);  //Green LED Off
  digitalWrite(LED_RED,LOW);     //Red LED On
  digitalWrite(RELAY,LOW);       //Turn off Relay
  delay(2000);
  lcd.clear();

  //add special char °
  byte Celsius[8] = {B11100,B10100,B11100,B0000,B00000,B00000,B00000,B00000};
  lcd.createChar(0, Celsius);


}
//=================================================================
//                  LOOP
//=================================================================
void loop(){
  double Temperature = ((5.0/1024.0) * analogRead(A0)) * 10;

  lcd.setCursor(0,0);

  lcd.print("T.  IST: ");
  //Serial.print("T.  IST: ");

  //Serial.print(Temperature);
  //Serial.print('\n');
  lcd.print(Temperature, 0);

  lcd.write((uint8_t)0);
  //Serial.print(" C");
  lcd.print("C");

//key input
  if(digitalRead(down_key)==LOW)
  {
    if(SetPoint>0)
    {
      SetPoint--;
    }
  }
  if(digitalRead(up_key)==LOW)
  {
    if(SetPoint<150)
    {
      SetPoint++;
    }
  }

//Display Set point on LCD
  lcd.setCursor(0,1);
  lcd.print("T. SOLL: ");
  //Serial.print("T. SOLL: ");

  lcd.print(SetPoint);
  //Serial.print(SetPoint);

  lcd.write((uint8_t)0);
  //Serial.print(" C");
  lcd.print("C");

//Check Temperature is in limit
unsigned long currentMillis = millis();

  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;

    if(Temperature > SetPoint)
    {
       digitalWrite(RELAY,LOW);    //Turn off heater
       digitalWrite(LED_RED,LOW);
       digitalWrite(LED_GREEN,HIGH);  //Turn on Green LED

      Serial.print("Turn off heater \n");
    }
    else
    {
      digitalWrite(RELAY,HIGH);    //Turn on heater
      digitalWrite(LED_GREEN,LOW);
      digitalWrite(LED_RED,HIGH);  //Turn on RED LED

      Serial.print("Turn on heater \n");
    }
  }

    delay(100); //Update at every 100mSeconds
}
//=================================================================