졸음운전을 방지하는 아두이노 동작을 하고 싶은데 일단 구글링 해서 기초적인 틀은 만든 것 같습니다.
원하는 행동이 열차기관사의 졸음운전방지처럼 일정시간 이상 버튼이 안눌리면 경보를 울리는 동작인데
어떤식으로 코딩을 해야될지 모르겠습니다. 초입 방식이라도 제시해주신다면 감사하겠습니다..
 
int in1 = 7;
int in2 = 8;
int in3 = 4;
int in4 = 5;
const int buttonPin = 2;
int buttonState = 0;     // current state of the button
int lastButtonState = 0; // previous state of the button
int startPressed = 0;    // the time button was pressed
int endPressed = 0;      // the time button was released
int timeHold = 0;        // the time button is hold
int timeReleased = 0;    // the time button is released

void setup() {
  pinMode(in1, OUTPUT);       // Motor A 방향설정1
  pinMode(in2, OUTPUT);       // Motor A 방향설정2
  pinMode(in3, OUTPUT);       // Motor B 방향설정1
  pinMode(in4, OUTPUT);       // Motor B 방향설정2
  pinMode(buttonPin, INPUT);
  Serial.begin(9600);
}
void loop() {
  if (Serial.available()) {
    char in_data;
    in_data = Serial.read();
    if (in_data == '1') {
      digitalWrite(in1, HIGH);
      digitalWrite(in2, LOW);
      digitalWrite(in3, HIGH);
      digitalWrite(in4, LOW);
      analogWrite(9, 127); 
      analogWrite(3, 127);  // 최대속도의 50%
    }
    else if (in_data == '2') {
      digitalWrite(in1, HIGH);
      digitalWrite(in2, LOW);
      digitalWrite(in3, HIGH);
      digitalWrite(in4, LOW);
      analogWrite(9, 179); 
      analogWrite(3, 179);  // 최대속도의 70%
    }
    else if (in_data == '3') {
      digitalWrite(in1, HIGH);
      digitalWrite(in2, LOW);
      digitalWrite(in3, HIGH);
      digitalWrite(in4, LOW);
      analogWrite(9, 255); 
      analogWrite(3, 255);  // 최대속도
      
      buttonState = digitalRead(buttonPin);
      
      if (buttonState != lastButtonState) {
          if (buttonState == HIGH) {
              startPressed = millis();
              timeReleased = startPressed - endPressed;
              if (timeReleased >= 500 && timeReleased < 1000) {
                  Serial.println("Button idle for half a second"); 
              }
              else if (timeReleased >= 1000) {
                  Serial.println("Button idle for one second or more"); 
              }
      }
      else {
          endPressed = millis();
          timeHold = endPressed - startPressed;
          if (timeHold >= 500 && timeHold < 1000) {
              Serial.println("Button hold for half a second"); 
          }
          else if (timeHold >= 1000) {
              Serial.println("Button hold for one second or more"); 
          }
      }
  }
  lastButtonState = buttonState; 
    }
    else {
      digitalWrite(in1, LOW);
      digitalWrite(in2, LOW);
      digitalWrite(in3, LOW);
      digitalWrite(in4, LOW);
    }
  }
}