int Trig = 12;//可以改
int Echo = 13;//可以改
int led1 = 2;//可以改

void setup() {
  Serial.begin(9600);
  pinMode(Trig, OUTPUT);
  pinMode(Echo, INPUT);
  pinMode(led1, OUTPUT);
  
}
void loop() {
  
  digitalWrite(Trig,HIGH);
  delayMicroseconds(5);
  digitalWrite(Trig,LOW);
  delayMicroseconds(5);
  float EchoTime = pulseIn(Echo,HIGH);
  float cmValue = EchoTime/29.4/2;
  Serial.println(cmValue);
  if(cmValue < 200){
    digitalWrite(led,HIGH);
  }
  else{
    digitalWrite(led,LOW);
  }
  /*digitalWrite(led1, (cmValue < 200) ? HIGH : LOW); /*三元運算符*/
  /*digitalWrite(led2, (cmValue < 100) ? HIGH : LOW);*/
  delay(1000);

}