 /* 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


unsigned long accumulator(bool standby) {
  unsigned long startTime, endTime = 0;
  int signalState, previousState = 0;
  
  while(!standby) {
    // read signal state

    Serial.print(" ");
    i++;

    // LED on if an RFID is detected (idle packet only contains 7 bytes)
    if(response[7] != NULL) {
      digitalWrite(ledPin, HIGH);
      // Machine is ready to fire, get ready to track time
