int echoPin = 2;
int trigPin = 3;

long waktu;
int jarak;
void setup() {
  // put your setup code here, to run once:
pinMode(echoPin,INPUT);
pinMode(trigPin, OUTPUT);

Serial.begin(9600);
pinMode(8,OUTPUT);
}
void loop() {
  // put your main code here, to run repeatedly:
digitalWrite(trigPin, LOW);
delayMicroseconds(2);
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);

waktu = pulseIn(echoPin,HIGH);
jarak = waktu*0.034/2;
Serial.println("jarak:"+ String (jarak) + " cm");
digitalWrite(8, HIGH);
delay(300);
digitalWrite(8, LOW);
delay(200);
}