     else {
       previousState = signalState;
     }
-  
   }
+  return 0;
 }
 
 


// command packet - start, address, data length, command, data[0 to 2], end
// response packet when idle - 0xAA, 0x00, 0x02, 0x01, 0x83, 0x80, 0xBB
const int ledPin = 13;
const int signalPin = 4;
char get_readID[] = { 0xAA , 0x00, 0x03, 0x25, 0x26, 0x00, 0x00, 0xBB };
byte response[11];
bool standby;
unsigned long elapsed_time;

void setup() {
  Serial.begin(57600);

/* RFID Reader
   Uses RDM880 breakout board with RX connected to pin 2 and TX connected to pin 3. 
   Another serial interface is added by including the Software Serial library.
   Dummy signal from 3.3 V is connected to pin 4.

   Input:
      RFID tag
