10_ultrasonic(초음파 거리재기)

const int trig_pin =11;
const int echo_pin =12;

void setup() {
  // put your setup code here, to run once:
  pinMode(trig_pin,OUTPUT);
  pinMode(echo_pin,INPUT);
  Serial.begin(115200);

}

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

  long duration = pulseIn(echo_pin,HIGH);
  long distance = (duration/2)/29.1;
  Serial.print(distance);
  Serial.println( "cm");
  delay(300);
}