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


void setup() {
  Serial.begin (115200); //bisa di ganti dengan 9600
pinMode(TRIG_PIN, OUTPUT );
pinMode(ECHO_PIN, INPUT );
pinMode(led1, OUTPUT );
pinMode(led2, 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 variable jara
delay(200);
//jika jarak kurang dari 50 led1 nyala
  if (jarak<50)
  {
    digitalWrite(led1,HIGH);
    digitalWrite(led2,LOW);
  }
  else
{
  digitalWrite(led1,LOW);
  digitalWrite(led2,HIGH);

}


}