#include <LiquidCrystal_I2C.h>
#include <DHT.h>
#define DHTPIN 4
#define DHTTYPE DHT22
DHT dht(DHTPIN,DHTTYPE);
LiquidCrystal_I2C lcd (0x27,16,2);
int button = 7;
int lasteState=-1;
float previousTemp = NAN;
float previousHumi = NAN;
unsigned long previousMillis = 0;
const long interval = 500;
int relay = 8;





void setup() {
pinMode(button, INPUT_PULLUP);
lcd.init();
lcd.backlight();
dht.begin();
pinMode(relay, OUTPUT);


}

void loop() {
  int stateB =digitalRead(button);
  float temp =dht.readTemperature();
  if (temp > 40.0)
  {
    digitalWrite(relay, HIGH);
  }
  else
  {

        digitalWrite(relay, LOW);


  }
  float humi =dht.readHumidity();

  if (stateB != lasteState)
  {
    lcd.clear();
    lasteState=stateB;
  }
  unsigned long currentMillis = millis();
  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;
  if ( stateB == 1)
  {
    if (!isnan(temp) && !isnan(humi)) { 
      lcd.setCursor(0,0);
      lcd.print("Temp:");
      lcd.print(temp);
      lcd.print(" C ");
      lcd.setCursor(0,1);
      lcd.print("humi:");
      lcd.print(humi);
      lcd.print("%");
      if (temp != previousTemp || humi != previousHumi) {
        previousTemp = temp;
        previousHumi = humi;
        
      }
      }
      else
      {
      lcd.setCursor(0, 0);
      lcd.print("Error reading");
      lcd.setCursor(0, 1);
      lcd.print("sensor data!");
      }
  }
  else
  {
    lcd.setCursor(0,0);
    lcd.print("Door is Open");
  }
  
  }
}