 char get_readID[] = { 0xAA , 0x00, 0x03, 0x25, 0x26, 0x00, 0x00, 0xBB };
 byte response[11];
 bool standby;
-unsigned long elapsed_time = 0;
+unsigned long elapsed_time;
 
 void setup() {
   Serial.begin(57600);


   Input:
      RFID tag

   Output:
      Serial number of tag scanned

   Operation:
      Reader waits until a tag is scanned, then prints the serial number of the tag

  digitalWrite(ledPin, LOW); 
  standby = true;
  response[7] = NULL;
  elapsed_time = 0;

  // read response from RDM880 and print
  int i = 0;
