#include <Wire.h> 

#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

#define trigPin A0 //Sensor Trig pin connected to Arduino pin A0

#define echoPin A1 //Sensor Echo pin connected to Arduino pin A1


long duration;
int distance;
int distanceInch;
const int relay = 2;


void setup()

{

  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(relay, OUTPUT);
  pinMode(relay, LOW);

  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("ULTRASONIC ACT.");
  delay(2000);
  lcd.setCursor(0,1);
  lcd.print("Ricardo Fulgar");
  delay(2000);
  lcd.clear();
  lcd.setCursor(0,0);  //Set LCD cursor to upper left corner, column 0, row 0
  lcd.print("Distance:");//Print Message on First Row
  lcd.setCursor(0,1);
  lcd.print("Distance:");


}



void loop()

{

  digitalWrite(trigPin, HIGH);

  delayMicroseconds(10);

  digitalWrite(trigPin, LOW);

  duration = pulseIn(echoPin, HIGH); //duration is the time the echoPin received HIGH

  distance = duration*0.034/2;

  distanceInch = distance*0.39;


  lcd.setCursor(9,0);    
  lcd.print(distance); //Print measured distance
  lcd.print(" cm");  //Print your units.
  lcd.setCursor(9,1);   
  lcd.print(distanceInch); //print measured distance
  lcd.print(" inch");  //Print your units. 
  delay(200); //pause to let things settle

  if(distance>300){

  digitalWrite(relay, HIGH);
  }
  else{
    digitalWrite(relay, LOW);
  }

}