get Distance

distance.ino

volatile int distance;

// パルスのエコーで距離を求める
float checkdistance_8_7() {
  digitalWrite(8, LOW);
  delayMicroseconds(2);
  digitalWrite(8, HIGH);
  delayMicroseconds(10);
  digitalWrite(8, LOW);
  float distance = pulseIn(7, HIGH) / 58.00;
  delay(10);
  return distance;
}

void setup() {
  distance = 0;
  // Trig
  pinMode(8, OUTPUT);
  // Echo
  pinMode(7, INPUT);
  // LED
  pinMode(LED_BUILTIN, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  distance = checkdistance_8_7();
  Serial.println(distance);
  if (distance < 50) {
    // 密だったらLED点灯
    digitalWrite(LED_BUILTIN, HIGH);
  } else {
    // 密じゃなかったらLED消灯
    digitalWrite(LED_BUILTIN, LOW);
  }
  delay(1000);
}