#define ECHO_PIN 2
#define TRIG_PIN 15

const int led1 = 21;
const int led2 = 19;
const int led3 = 18;
const int led4 = 5;
const int buzzer = 4;

void setup() {
  Serial.begin(115200);
  pinMode(LED_BUILTIN, OUTPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);
  pinMode(led4, OUTPUT);
  pinMode(buzzer, 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() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  int duration = pulseIn(ECHO_PIN, HIGH);
  float distance = duration * 0.034 / 2;
  Serial.print("Jarak: ");
  Serial.println(distance);

  if(distance > 50)  {
    digitalWrite(led1, HIGH);
  }else{
    digitalWrite(led1, LOW);
  }

  if(distance > 100) {
    digitalWrite(led2, HIGH);
  }else{
    digitalWrite(led2, LOW);
  }

  if(distance > 200) {
    digitalWrite(led3, HIGH);
  }else{
    digitalWrite(led3, LOW);
  }

  if(distance > 300) {
    digitalWrite(led4, HIGH);
    digitalWrite(buzzer, HIGH);
  }else{
    digitalWrite(led4, LOW);
    digitalWrite(buzzer, LOW);
  }
}