#define ECHO_PIN 2
#define TRIG_PIN 3
#define hijau 10
#define putih 11
#define kuning 12
#define merah 13

int buzzer=8;
void setup() {
  Serial .begin(115200);
  pinMode(hijau, OUTPUT);
  pinMode(putih, OUTPUT);
  pinMode(kuning, OUTPUT);
  pinMode(merah, OUTPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
}
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() {
  float distance = readDistanceCM();
  if (distance <= 30){
    digitalWrite(merah, HIGH);
    tone(buzzer,1030);
  }else{
    digitalWrite(merah, LOW);
  }
  
  if (distance >= 30 && distance < 100 ){
    digitalWrite(kuning, HIGH);
    tone(buzzer,1030);
  }else{
    digitalWrite(kuning, LOW);
  }

  if (distance >= 100 && distance < 200 ){
    digitalWrite(putih, HIGH);
    noTone(buzzer);
  }else{
    digitalWrite(putih, LOW);
  }

  if (distance >= 200 ){
    digitalWrite(hijau, HIGH);
    noTone(buzzer);
  }else{
    digitalWrite(hijau, LOW);
  }
}