#include <Wire.h>
#include <LiquidCrystal_I2C.h>
const int trigPin = 11; 
const int echoPin = 12;
const int buzzer = 10;

LiquidCrystal_I2C lcd(0x27,16,2);
long duration; 
int distance; 

void setup() {
 Serial.begin(9600); //Kecepatan pengiriman data 9600 bit per detik 
  pinMode(trigPin, OUTPUT); //Setting Trigger sebagai output 
  pinMode(echoPin, INPUT); //Setting Echo sebagai input 
  pinMode(buzzer, OUTPUT); //Setting Buzzer sebagai output 
}

void loop() {
digitalWrite(trigPin, LOW); //Trigger off mengirimkan sinyal 
delayMicroseconds(2); //Selang waktu 0.002 detik 
digitalWrite(trigPin, HIGH); //Trigger on mengirimkan sinyal 
delayMicroseconds(10); // Selang waktu 0.01 detik 
digitalWrite(trigPin, LOW); //Trigger off mengirimkan sinyal  

duration = pulseIn(echoPin, HIGH);
distance= duration*0.034/2;

 if (distance <10){ //Jika jarak benda < 10 cm 
    tone(buzzer, 1000); 
    delay(100);
    noTone(buzzer); 
    delay(100);   }                
 if(distance >10){ //Jika jarak benda > 10 cm 
    noTone(buzzer);} //Buzzer off                
}