// Variable Declaration
#include <LiquidCrystal.h>

LiquidCrystal lcd(12, 14, 27, 26, 33, 32);

const int trigPin = 18;
const int echopin = 5;
const int Btn = 4;
const int relay = 25;
const int ImpulseDuration = 5000;

#define SOUND_SPEED 0.034;

long duration;
float distance;
int BtnStatus;

void setup() {
  
  Serial.begin(9600);

  lcd.begin(16, 2);
  pinMode(relay, OUTPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(echopin, INPUT);
  pinMode(Btn, INPUT_PULLUP);

}

void loop() {
  
    // Clear trigger & init btn
  digitalWrite(trigPin, LOW);
  digitalRead(Btn);
  delay(2);
  BtnStatus = digitalRead(Btn);
  delay(10);
 
  // Send pulse
  digitalWrite(trigPin, HIGH);
  delay(10);
  
  digitalWrite(trigPin, LOW);

  duration = pulseIn(echopin, HIGH);
  distance = duration * 0.017;
  lcd.setCursor(3,0);
  lcd.println(distance);

  if(BtnStatus != HIGH or distance > 300){
    open();
    delay(ImpulseDuration);
    close();
  }
  else {
    close();
    delay(10);
}
// delay(100);
}

void open() {
  digitalWrite(relay, HIGH);
}

void close() {
  digitalWrite(relay, LOW);
}