#define trigPin 5 // Pin trigger sensor HC-SR04
#define echoPin 18 // Pin echo sensor HC-SR04

#define greenLED 4 // Green LED pin
#define yellowLED 2 // Yellow LED pin
#define blueLED 15 // Blue LED pin
#define redLED 19// Red LED pin

void setup() {
  Serial.begin(9600);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  
  pinMode(greenLED, OUTPUT);
  pinMode(yellowLED, OUTPUT);
  pinMode(blueLED, OUTPUT);
  pinMode(redLED, OUTPUT);
}

void loop() {
  long duration, distance;
  
  // Sending ultrasonic pulse
  digitalWrite(trigPin, LOW); 
  delayMicroseconds(2); 
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10); 
  digitalWrite(trigPin, LOW);
  
  // Receiving duration of the echo
  duration = pulseIn(echoPin, HIGH);
  
  // Calculating distance based on duration
  distance = duration * 0.034 / 2;
  
  // Indicating status with LEDs and serial print
  if (distance >= 180) {
    digitalWrite(greenLED, HIGH); // Green LED for "Safe"
    digitalWrite(yellowLED, LOW);
    digitalWrite(blueLED, LOW);
    digitalWrite(redLED, LOW);
    Serial.println("Status: Aman");
  } else if (distance >= 150 && distance < 180) {
    digitalWrite(greenLED, LOW);
    digitalWrite(yellowLED, HIGH); // Yellow LED for "Alert Level 1"
    digitalWrite(blueLED, LOW);
    digitalWrite(redLED, LOW);
    Serial.println("Status: Siaga 1");
  } else if (distance >= 120 && distance < 150) {
    digitalWrite(greenLED, LOW);
    digitalWrite(yellowLED, LOW);
    digitalWrite(blueLED, HIGH); // Blue LED for "Alert Level 2"
    digitalWrite(redLED, LOW);
    Serial.println("Status: Siaga 2");
  } else {
    digitalWrite(greenLED, LOW);
    digitalWrite(yellowLED, LOW);
    digitalWrite(blueLED, LOW);
    digitalWrite(redLED, HIGH); // Red LED for "Alert Level 3"
    Serial.println("Status: Siaga 3");
  }
  
  delay(1000); // 1 second delay between readings
}