//program sensor jarak HC SR04
#define ECHO_PIN 2
#define TRIG_PIN 3
#define led1 4
#define led2 5
#define led3 6
int durasi;
float jarak;



void setup() {
  Serial.begin(115200); //bisa diganti dengan 9600 
  pinMode (TRIG_PIN, OUTPUT);
  pinMode (ECHO_PIN, INPUT); 
  pinMode (led1, OUTPUT) ;
  pinMode (led2, OUTPUT) ;
  pinMode (led3, OUTPUT) ;
}

void loop() {
  //menghitung jarak
  digitalWrite(TRIG_PIN, LOW) ;
  delayMicroseconds (2) ;
  digitalWrite(TRIG_PIN, HIGH); //mengirim sinyal
  delayMicroseconds (10) ;
  digitalWrite (TRIG_PIN, LOW) ;
  durasi = pulseIn (ECHO_PIN, HIGH); //menerima sinyal kemudian di hitung durasinya
  jarak = durasi * 0.034 / 2; // menghitung jarak berdasarkan rumus
  //menampilkan jarak di serial monitor
  Serial.print ("Jarak:") ; //menampilkan tulisan jarak
  Serial.println(jarak) ; //menampilkan isi variabel jarak
  delay(200);

    if (jarak < 50) 
    {
    digitalWrite(led1, HIGH);
    digitalWrite(led2, LOW);
    digitalWrite(led3, LOW);
    } 
     else if (jarak > 50 && jarak < 70) 
     {
     digitalWrite(led1, LOW);
     digitalWrite(led2, HIGH);
     digitalWrite(led3, LOW);
     } 
      else 
      {
      digitalWrite(led1, LOW);
      digitalWrite(led2, LOW);
      digitalWrite(led3, HIGH);
      }
}