int Trig =12;//發出聲波
int Echo =14;//接收聲波

void setup()
{
  Serial.begin(115200);
  pinMode(Trig, OUTPUT);
  pinMode(Echo, INPUT);
}

void loop() 
{
  digitalWrite(Trig, LOW); //關閉
  delayMicroseconds(5);
  digitalWrite(Trig, HIGH);//啟動
  delayMicroseconds(10); 
  digitalWrite(Trig, LOW); //關閉
  
  float EchoTime = pulseIn(Echo, HIGH); //傳回時間
  float CMValue = EchoTime * 34 / 1000 / 2; //轉換成距離
  
  Serial.println(CMValue);
  delay(50);

}