#define echoPin 7
#define trigPin 8
int ledRed = 3;
int ledYellow = 2;
int ledGreen = 4;

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

void loop() {
  // put your main code here, to run repeatedly:
  long jarak, ketinggianAir, duration;
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  jarak = (duration / 2) / 28.5;
  ketinggianAir = 18.5 - jarak;
  Serial.print("Ketinggian Air = ");
  Serial.print(ketinggianAir);
  Serial.println(" cm");

  if (ketinggianAir < 5) {
    // LED Merah berkedip cepat
    digitalWrite(ledYellow, LOW);
    digitalWrite(ledGreen, LOW);
    for (int i = 0; i < 10; i++) {
      digitalWrite(ledRed, HIGH);
      delay(50);
      digitalWrite(ledRed, LOW);
      delay(50);
    }
    Serial.println("Air dalam batas tidak aman");
  } else if (ketinggianAir >= 5 && ketinggianAir < 10) {
    // LED Kuning berkedip pelan
    digitalWrite(ledRed, LOW);
    digitalWrite(ledGreen, LOW);
    for (int i = 0; i < 3; i++) {
      digitalWrite(ledYellow, HIGH);
      delay(500);
      digitalWrite(ledYellow, LOW);
      delay(500);
    }
    Serial.println("Air hampir habis");
  } else {
    // LED Hijau menyala terus menerus
    digitalWrite(ledRed, LOW);
    digitalWrite(ledYellow, LOW);
    digitalWrite(ledGreen, HIGH);
    Serial.println("Air dalam batas aman");
  }
  delay(1000);
}