#define ECHO_pin 5
#define TRIG_pin 4
#define led_Merah 8
#define led_Kuning 7
#define led_Hijau 6

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(TRIG_pin, OUTPUT);
  pinMode(ECHO_pin, INPUT);
  pinMode(led_Merah, OUTPUT);
  pinMode(led_Kuning, OUTPUT);
  pinMode(led_Hijau, OUTPUT);
}

float readDistanceCM() {
  digitalWrite(TRIG_pin, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_pin, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_pin, LOW);
  int duration = pulseIn(ECHO_pin, HIGH);
  return duration * 0.034 / 2;
}

void loop() {
  // put your main code here, to run repeatedly:
  float distance = readDistanceCM();

  Serial.print("Measured distance: ");
  Serial.println(readDistanceCM());
  

  if (distance <=50){
    digitalWrite(led_Merah, HIGH);
    digitalWrite(led_Kuning, LOW);
    digitalWrite(led_Hijau, LOW);
  }else if (distance <= 100){
    digitalWrite(led_Merah, LOW);
    digitalWrite(led_Kuning, HIGH);
    digitalWrite(led_Hijau, LOW);
  }else{
    digitalWrite(led_Merah, LOW);
    digitalWrite(led_Kuning,LOW);
    digitalWrite(led_Hijau, HIGH);
  }
  delay(100);

}