title: USB RFID reader + raspberry pi
body: <p>i have usb RFID reader connected to raspberry pi 
  the RFID reader is the Chinese brand it act like keyboard and it read the first 10 digit </p>
  
  <p>so what i am trying to do here is read from the card and Compare with stored number in my code </p>
  
  <pre><code>#!/usr/bin/env python
  import time
  import sys
  
  card = '0019171125'        # Stored good card number consider using a list or a file.
  def main():                # define a main function.
  while True:                # loop until the program encounters an error.
  sys.stdin = open('/dev/tty0', 'r')
  RFID_input = input()            
  if RFID_input == card:      # coppare the stored number to the input and if True execute code.
    print "Access Granted" 
    print "Read code from RFID reader:{0}".format(RFID_input)
  else:                    # and if the condition is false excecute this code.
    print "Access Denied"
    tty.close()
   main()                       # call the main function.
  </code></pre>
  
  <p>but this error keep showing</p>
  
  <blockquote>
    <p>RFID_input = input()<br>
                              ^
    IndentationError: unindent does not match any outer indentation level </p>
  </blockquote>
  
  <p>any suggestion </p>