arduino学习入门（超声波传感器）

 

volatile double a;

 

float checkdistance_9_10() {

  digitalWrite(9, LOW);

  delayMicroseconds(2);

  digitalWrite(9, HIGH);

  delayMicroseconds(10);

  digitalWrite(9, LOW);

  float distance = pulseIn(10, HIGH) / 58.00;

  delay(10);

  return distance;

}

 

void setup(){

  a = 0;

  pinMode(9, OUTPUT);

  pinMode(10, INPUT);

  Serial.begin(9600);

  pinMode(2, OUTPUT);

}

 

void loop(){

  while (true) {

    a = checkdistance_9_10();

    Serial.println(a);

    if (a > 20 && a < 120) {

      digitalWrite(2,HIGH);

      delay(1000);

      digitalWrite(2,LOW);

 

    }

    delay(1000);

  }

 

  checkdistance_9_10();

 

}

 

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