#include <Arduino.h>

const int trigPin = 2;  
const int echoPin = 4;  
const int led1Pin = 19; 
const int led2Pin = 18;  
const int led3Pin = 5;  
const int led4Pin = 17;  
const int buzzerPin = 13;  

#define max_distance 400

void setup() {
  Serial.begin(115200);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(led1Pin, OUTPUT);
  pinMode(led2Pin, OUTPUT);
  pinMode(led3Pin, OUTPUT);
  pinMode(led4Pin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
}

void loop() {
  
  long durasi, jarak;
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  durasi = pulseIn(echoPin, HIGH);
  jarak = (durasi / 2) / 29.1;  

Serial.println("jarak");
Serial.println(jarak);
Serial.println("cm");
delay(500);

  
  if (jarak > 300) {
    digitalWrite(led1Pin, HIGH);
    digitalWrite(led2Pin, HIGH);
    digitalWrite(led3Pin, HIGH);
    digitalWrite(led4Pin, HIGH);
    digitalWrite(buzzerPin, HIGH);
  } else if (jarak > 200) {
    digitalWrite(led1Pin, HIGH);
    digitalWrite(led2Pin, HIGH);
    digitalWrite(led3Pin, HIGH);
    digitalWrite(led4Pin, LOW);
    digitalWrite(buzzerPin, LOW);
  } else if (jarak > 100) {
    digitalWrite(led1Pin, HIGH);
    digitalWrite(led2Pin, HIGH);
    digitalWrite(led3Pin, LOW);
    digitalWrite(led4Pin, LOW);
    digitalWrite(buzzerPin, LOW);
  } else if (jarak > 50) {
    digitalWrite(led1Pin, HIGH);
    digitalWrite(led2Pin, LOW);
    digitalWrite(led3Pin, LOW);
    digitalWrite(led4Pin, LOW);
    digitalWrite(buzzerPin, LOW);
  } else {
    digitalWrite(led1Pin, LOW);
    digitalWrite(led2Pin, LOW);
    digitalWrite(led3Pin, LOW);
    digitalWrite(led4Pin, LOW);
    digitalWrite(buzzerPin, LOW);
  }

  delay(500);  
}