const int trigPin = 4;
const int echoPin = 15;
const int ledBlue = 5;
const int ledGreen = 18;
const int ledYellow = 19;
const int ledRed = 21;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(ledBlue, OUTPUT);
  pinMode(ledGreen, OUTPUT);
  pinMode(ledYellow, OUTPUT);
  pinMode(ledRed, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  long duration, distance;
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = duration/58.2;

  if (distance > 50) {
    digitalWrite(ledBlue, HIGH);
    digitalWrite(ledGreen, LOW);
    digitalWrite(ledYellow, LOW);
    digitalWrite(ledRed, LOW);
  }if (distance >100) {
    digitalWrite(ledBlue, HIGH);
    digitalWrite(ledGreen, HIGH);
    digitalWrite(ledYellow, LOW);
    digitalWrite(ledRed, LOW);
  }if (distance > 200){
    digitalWrite(ledBlue, HIGH);
    digitalWrite(ledGreen, HIGH);
    digitalWrite(ledYellow, HIGH);
    digitalWrite(ledRed, LOW);
  }if (distance > 300) {
    digitalWrite(ledBlue, HIGH);
    digitalWrite(ledGreen, HIGH);
    digitalWrite(ledYellow, HIGH);
    digitalWrite(ledRed, HIGH);
  }Serial.print("Tinggi air : ");
  Serial.print(distance);
  Serial.print(" cm");
  Serial.println(", by : A16 - ABU YAZID BUSTOMI");
  delay(500);
}