// on_off_time at 10 ms to speed up the time
// on_off_time at 7/8 ms to speed up the time backwards

// Open the serial to specify the on-off_time in ms
// Close and reopen to insert a new one

int on_off_time = 1000; 

void setup() {
  Serial.begin(9600);
  pinMode(9, OUTPUT);
  pinMode(10, OUTPUT);
}

void loop() {
  // // DEBUG with Serial Monitor //
  // if (Serial.available() > 0) { // check if there's any incoming serial data
  //   int new_delay = Serial.parseInt(); // read the incoming integer value
  //   if (new_delay >= 0 && new_delay <= 1023) { // check if the value is within range
  //     on_off_time = new_delay; // set the new threshold value
  //     Serial.end();
  //   }
  // }
  // digitalWrite(10, HIGH);
  // digitalWrite(9, LOW);
  // delay(on_off_time);
  // digitalWrite(10, LOW);
  // digitalWrite(9, HIGH);
  // delay(on_off_time);
  // /////////////////////////////////


  if (Serial.available() >= 1) {
    byte data[1];
    Serial.readBytes(data, 1); // 1 bytes are send by the python script each second
    int firstBit = (data[0] & 0b00000001);  // extract the first bit and shift it to the rightmost position
    if (firstBit == 1) {
      digitalWrite(10, HIGH);
      digitalWrite(9, LOW);
      delay(on_off_time);
      digitalWrite(10, LOW);
      digitalWrite(9, HIGH);
      delay(on_off_time);
    } else {
      // do something if the first bit is 0
    }
  }
}