#include <Wire.h>// lcd
#include <LiquidCrystal_I2C.h>// lcd
LiquidCrystal_I2C lcd(0x27, 16, 2);// lcd

#include<Servo.h>// servo
Servo servo1;// servo


float duration_us, distance_cm;// ultrasonic


void setup() {
  // put your setup code here, to run once:

  lcd.init();          // Initialize LCD
  lcd.backlight();     // Turn on backlight
  lcd.setCursor(0, 0);
  lcd.print("I2C LCD Demo");
  delay(1000); // Pause before starting loop


  Serial.begin (9600);
  servo1.attach(3);   // for servo 
  servo1.write(0); // for initial condition at 0 degree

  pinMode(7, OUTPUT); // set trig pin to output mode
  pinMode(8, INPUT);  // set echo pin to input mode
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(7, LOW);
  delayMicroseconds(10);
  digitalWrite(7, HIGH);
  delayMicroseconds(10);
  digitalWrite(7, LOW);
  duration_us = pulseIn(8, HIGH);
 distance_cm= duration_us * 0.0344 / 2;
  Serial.print("distance: ");
  Serial.print(distance_cm);
  Serial.println(" cm");
  delay(500);

  if(distance_cm<5){
    servo1.write(90);
  }
  else{
    servo1.write(0);
  }

  // for display the result on lcd display
  lcd.setCursor(0, 1);      // Row 1 (second line)
  lcd.print("Distance : ");     
  lcd.print(distance_cm);       // Display the counter value
  lcd.print("   ");         // Clear any old digits
}