#define TRIG_PIN 9
#define ECHO_PIN 10
#define RED_LED 5
#define YELLOW_LED 4
#define GREEN_LED 7
#define BUZZER 6  // Buzzer connected to pin 6

void setup() {
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(RED_LED, OUTPUT);
  pinMode(YELLOW_LED, OUTPUT);
  pinMode(GREEN_LED, OUTPUT);
  pinMode(BUZZER, OUTPUT);  // Set buzzer pin as output
  Serial.begin(9600);
}

long getDistance() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  long duration = pulseIn(ECHO_PIN, HIGH);
  long distance = duration * 0.034 / 2; // Convert to cm
  return distance;
}

void loop() {
  long distance = getDistance();
  
  Serial.print("Water Distance: ");
  Serial.print(distance);
  Serial.println(" cm");

  // LED + Buzzer Logic based on water distance
  if (distance <= 7) {
    digitalWrite(RED_LED, HIGH);
    digitalWrite(YELLOW_LED, LOW);
    digitalWrite(GREEN_LED, LOW);
    digitalWrite(BUZZER, HIGH);  // Buzzer ON
  } 
  else if (distance > 8 && distance <= 18) {
    digitalWrite(RED_LED, LOW);
    digitalWrite(YELLOW_LED, HIGH);
    digitalWrite(GREEN_LED, LOW);
    digitalWrite(BUZZER, LOW);   // Buzzer OFF
  } 
  else if (distance > 19) {
    digitalWrite(RED_LED, LOW);
    digitalWrite(YELLOW_LED, LOW);
    digitalWrite(GREEN_LED, HIGH);
    digitalWrite(BUZZER, LOW);   // Buzzer OFF
  }

  delay(1000); // Wait 1 second before next reading
}