const int trigPin = 9;
const int echoPin = 10;
const int redPin = 2;
const int yellowPin = 3;
const int greenPin = 4;

void setup() {
  Serial.begin(9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(redPin, OUTPUT);
  pinMode(yellowPin, OUTPUT);
  pinMode(greenPin, OUTPUT);
}

void loop() {
  long duration, distance;
  digitalWrite(trigPin, LOW);  
  delayMicroseconds(2); 
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10); 
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;
  Serial.print("Distance: ");
  Serial.println(distance);
  
  if (distance > 50) {
    digitalWrite(redPin, HIGH);
    digitalWrite(yellowPin, LOW);
    digitalWrite(greenPin, LOW);
    Serial.println("Status Bahaya");
  }
  else if (distance >= 25 && distance <= 50) {
    digitalWrite(redPin, LOW);
    digitalWrite(yellowPin, HIGH);
    digitalWrite(greenPin, LOW);
    Serial.println("Hati-Hati");
  }
  else {
    digitalWrite(redPin, LOW);
    digitalWrite(yellowPin, LOW);
    digitalWrite(greenPin, HIGH);
    Serial.println("Status Aman");
  }
  delay(500);
}