#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27,16,2);
int trigPin = 8;
int echoPin = 9;

int LED = 4;
int buzzer =3; 

//define variable
long duration;
int distance;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  lcd.init();
  lcd.clear();         
  lcd.backlight();
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

//int LED = 3;
//int buzzer =4; 
   pinMode(LED, OUTPUT);
      pinMode(buzzer, OUTPUT);


}

void loop() {



  // put your main code here, to run repeatedly:
  //Clears the trigPin
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  //Set the trigPin on HIGH for 10 micro seconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  //Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  //Calculate the distance
  distance = duration*0.034/2;


if (distance <=20 && distance >=10)
{
 // display warning
 // led on
 //
  lcd.setCursor(1,0);   //Set cursor to character 2 on line 0
    lcd.print("       ");  
  lcd.print("Warning");  

  digitalWrite(LED, HIGH);

}

if (distance <10)
{
 // display warning
 // led blinking
  // buzzer sound.. 
 // digitalWrite(led1, HIGH);
  lcd.print("                     ");  
   lcd.print("Warning: too close");  

digitalWrite(LED, HIGH);

  tone(buzzer, 1000);
  delay (1000);
   noTone(buzzer);
   delay (1000);


}



}