#define ECHO_PIN 2
#define TRIG_PIN 15
#define RED_LED 19
#define YELLOW_LED 18
#define BLUE_LED 5

void setup() {
  Serial.begin(115200);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(RED_LED, OUTPUT);
  pinMode(YELLOW_LED, OUTPUT);
  pinMode(BLUE_LED, OUTPUT);
}

float readDistanceCM() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  int duration = pulseIn(ECHO_PIN, HIGH);
  return duration * 0.034 / 2;
}

void loop() {
  float distance = readDistanceCM();

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

  if (distance > 200) {
    digitalWrite(RED_LED, HIGH);
    digitalWrite(YELLOW_LED, HIGH);
    digitalWrite(BLUE_LED, HIGH);
  } else if (distance > 100) {
    digitalWrite(RED_LED, HIGH);
    digitalWrite(YELLOW_LED, HIGH);
    digitalWrite(BLUE_LED, LOW);
  } else if (distance > 50) {
    digitalWrite(RED_LED, HIGH);
    digitalWrite(YELLOW_LED, LOW);
    digitalWrite(BLUE_LED, LOW);
  } else {
    digitalWrite(RED_LED, LOW);
    digitalWrite(YELLOW_LED, LOW);
    digitalWrite(BLUE_LED, LOW);
  }

  delay(100);
}