int ledRed = 4;
int ledBlue = 5;
int ledYellow = 18;
int ledGreen = 19;

#define ECHO_PIN 2
#define TRIG_PIN 15

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(ECHO_PIN, OUTPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ledRed, OUTPUT);
  pinMode(ledYellow, OUTPUT);
  pinMode(ledGreen, OUTPUT);
  pinMode(ledBlue, OUTPUT);
}

void loop() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  int duration = pulseIn(ECHO_PIN, HIGH);
  float distance = duration * 0.034/2;

  Serial.print("Jarak: ");
  Serial.println(distance); 

  if (distance >50){
    digitalWrite(ledRed, HIGH);
    digitalWrite(ledGreen, LOW);
    digitalWrite(ledYellow, LOW);
    digitalWrite(ledBlue, LOW);
    delay(500);
   
  } if (distance >100) {
    digitalWrite(ledRed, HIGH);
    digitalWrite(ledGreen, LOW);
    digitalWrite(ledYellow, LOW);
    digitalWrite(ledBlue, HIGH);
    delay(500);

  } if (distance >200 ) {
    digitalWrite(ledRed, HIGH);
    digitalWrite(ledGreen, LOW);
    digitalWrite(ledYellow, HIGH);
    digitalWrite(ledBlue, HIGH);
    delay(500);

  } if (distance >300) {
    digitalWrite(ledRed, HIGH);
    digitalWrite(ledGreen, HIGH);
    digitalWrite(ledYellow, HIGH);
    digitalWrite(ledBlue, HIGH);
    delay(500);
  }
  else {
    digitalWrite(ledGreen, LOW);
    digitalWrite(ledRed, LOW);
    digitalWrite(ledYellow, LOW);
    digitalWrite(ledBlue, HIGH);
  }
  
}