const int echo = 6;
const int trig = 9;
int led = 7;
long durasi,jarak ;

void setup() {
Serial.begin(9600);
pinMode(led, OUTPUT);
pinMode(echo,INPUT);
pinMode(trig,OUTPUT);
}

void loop() {
digitalWrite(trig, HIGH);
delayMicroseconds(7);
digitalWrite(trig, LOW);
delayMicroseconds(7);
digitalWrite(trig, HIGH);
delayMicroseconds(7);


durasi = pulseIn(echo,HIGH);
jarak = (durasi / 2)/ 29.1;
Serial.println(jarak);
if(jarak <=30){
  digitalWrite(led, LOW);
}
else {
  digitalWrite(led, HIGH);
}
}