#include <Wire.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16,2);
const int triggerPin = 3;
const int echoPin = 2;
#define buzzerPin 11
const int LED1 = 8;
const int LED2 = 9;
const int LED3 = 10;
int frekuensi = 250;

long durasi;
int jarak;

void setup() {
 lcd.backlight();
 lcd.init();
 lcd.setCursor(0, 0);
 lcd.print("PROGRAM MULAI");
 lcd.clear();
 Serial.begin(9600);
 pinMode(triggerPin, OUTPUT); 
 pinMode(echoPin, INPUT);  
 pinMode(buzzerPin, OUTPUT);  
 pinMode(LED1, OUTPUT); 
 pinMode(LED2, OUTPUT);
 pinMode(LED3, OUTPUT);   
    
}

void loop() {
 digitalWrite(triggerPin, LOW);
  delayMicroseconds(2);
  digitalWrite(triggerPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(triggerPin, LOW);
  durasi = pulseIn(echoPin, HIGH);
  jarak = durasi * 0.034 / 2;

  if (jarak > 60) {
    digitalWrite(LED1, HIGH);
    digitalWrite(LED2, LOW);
    digitalWrite(LED3, LOW);
    lcd.setCursor(0, 0);
    lcd.println("JARAK: ");
    lcd.setCursor(7, 0);
    lcd.print(jarak);
    lcd.setCursor(12, 0);
    lcd.print("CM");
    lcd.setCursor(0, 1);
    lcd.print("HATI HATI");
  } 
  else if(jarak <= 60 && jarak >= 20){
    digitalWrite(LED2, HIGH);
    digitalWrite(LED1, LOW);
    digitalWrite(LED3, LOW);
    lcd.setCursor(0, 0);
    lcd.println("JARAK: ");
    lcd.setCursor(7, 0);
    lcd.print(jarak);
    lcd.setCursor(12, 0);
    lcd.print("CM");
    lcd.setCursor(0, 1);
    lcd.print("WASPADA");
  }
  else if(jarak < 20){
    digitalWrite(LED3, HIGH);
    digitalWrite(LED2, LOW);
    digitalWrite(LED1, LOW);
    lcd.setCursor(0, 0);
    lcd.println("JARAK: ");
    lcd.setCursor(7, 0);
    lcd.print(jarak);
    lcd.setCursor(12, 0);
    lcd.print("CM");
    lcd.setCursor(0, 1);
    lcd.print("BERBAHAYA");
  tone (buzzerPin, frekuensi);
  delay(250);
  noTone(buzzerPin);
  delay(250);
  }
}