Menghitung jarak dengan Ultrasonic

#include <HCSR04.h>

#define trigger 4
#define echo 2
UltraSonicDistanceSensor distanceSensor(echo, trigger);
void setup () {
Serial.begin(9600);
}
void loop () {
Serial.println(distanceSensor.measureDistanceCm());
delay(1000);
}