const uint8_t INPUT_PIN = 2;

void setup() {
  Serial.begin(9600);

  pinMode(INPUT_PIN, INPUT);
}

uint8_t inputValue = 0;
bool isDetectedMotion = false; 
void loop() {
  inputValue = digitalRead(INPUT_PIN);
  if(inputValue == HIGH) {
    if(!isDetectedMotion) {
      Serial.println("動きを検出しました");

      isDetectedMotion = true;
    }
  } else if(inputValue == LOW) {
    if(isDetectedMotion) {
      isDetectedMotion = false;
    }
  }
}