Arduino timer final

char* digitPinsOff[4] = {"l", "i", "h", "f"};
char* digitPinsOn[4]  = {"L", "I", "H", "F"};
char* digits[10] = {
  "KGDBAJkgdbaj", "GDgd", "KGEABkgeab", "KGEDBkgedb", "JEGDjegd",
  "KJEDBkjedb", "KJABDEkjabdeH", "KGDkgd", "ABDEJGKabdejgk", "BDEJGEKbdejgk"
};
int displayed[4] = {6, 1, 9, 7};
int received[4] = {0, 0, 0, 0};

void setup() {
  for (int i = 2; i < 14; i++) {
    pinMode(i, OUTPUT);
    digitalWrite(i, LOW);
  }
  Serial.begin(9600);
}

void loop() {
  // displays the number 2169.
  // Uh.
  displayDigitAt(1, displayed[0]);
  displayDigitAt(2, displayed[1]);
  displayDigitAt(3, displayed[2]);
  displayDigitAt(4, displayed[3]);
  if (Serial.available() > 0) {
    int i = 0;
    int j = 0;
    while (i < 4 && j < 1000) {
      char unsafe = Serial.read();
      if ('0' <= unsafe && unsafe <= '9') {
        received[i] = unsafe - '0';
        i++;
      } else {
        received[i] = displayed[i];
      }
      j++;
      displayDigitAt(1, displayed[0]);
      displayDigitAt(2, displayed[1]);
      displayDigitAt(3, displayed[2]);
      displayDigitAt(4, displayed[3]);
      //Serial.write(unsafe);
    }
    for (int i = 0; i < 4; i++) {
      displayed[i] = received[i];
    }
    //Serial.write("\n");
  }
}

void displayDigitAt(int pos, int digitToDisplay) {
  parseLetter(digitPinsOff[pos - 1]);
  parseLetter(digits[digitToDisplay]);
  parseLetter(digitPinsOn[pos - 1]);
}


void parseLetter(char* str) {
  int len = strlen(str);
  for (int i = 0; i < len; i++) {
    char pinCode = str[i];
    if (65 <= pinCode && pinCode <= 76) {
      digitalWrite(pinCode - 63, HIGH);
    }
    else {
      digitalWrite(pinCode - 95, LOW);
    }
  }
}