 
 #define FETCH_INTERVAL 100
 #define POST_INTERVAL 5000
+
+#define TAG_LENGTH 12
 
 const int numLedSamples = POST_INTERVAL / FETCH_INTERVAL;
 int ledSamples[numLedSamples];

          setLockState(false);
          break;
      }
      while (xbeeSerial.available())
        xbeeSerial.read();
      break;

uint16_t fifoCount;     // count of all bytes currently in FIFO
uint8_t fifoBuffer[64];

char rfidTag[TAG_LENGTH + 1];

// Software serial for XBee module
SoftwareSerial xbeeSerial(2, 3); // RX, TX
// Hardware serial for RFID reader
#define rfidSerial Serial

void setup() {
  // Setup serials
  xbeeSerial.begin(SERIAL_BAUDRATE);
  rfidSerial.begin(SERIAL_BAUDRATE);

  // Setup lock
  pinMode(A0, OUTPUT);
