#define ultrasonic_trigger 2
#define ultrasonic_echo 3
#define LED 12
#define Buzzer 9
long timer;
int jarak;
void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(LED, OUTPUT);
  pinMode(Buzzer, OUTPUT);
  pinMode(ultrasonic_trigger, OUTPUT);
  pinMode(ultrasonic_echo, INPUT);


}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(ultrasonic_trigger, LOW);
  delayMicroseconds(2);
  digitalWrite(ultrasonic_trigger, HIGH);
  delayMicroseconds(10);
  digitalWrite(ultrasonic_trigger, LOW);

  timer = pulseIn(ultrasonic_echo, HIGH);
  jarak = timer/58.2;

  if(jarak <= 6) {
    digitalWrite(LED, HIGH);
    digitalWrite(Buzzer, HIGH);
    delay(500);
    digitalWrite(LED, LOW);
    digitalWrite(Buzzer, LOW);
    delay(500);
  }

  Serial.print("jarak= ");
  Serial.print(jarak);
  Serial.print(" cm");
  Serial.println();
  delay(50);

}