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#!/usr/bin/env python
# encoding: utf-8
"""
rfid.py
The RFID reader and RFID card classes
"""
__version_info__ = (0, 0, 1)
__version__ = '.'.join(map(str, __version_info__))
__author__ = "Willem van der Jagt"
import serial
class Reader(object):
"""The RFID reader class. Reads cards and returns their id"""
def __init__(self, port_name, baudrate, string_length, timeout=1):
"""Constructor
parameters:
port_name : the device name of the serial port
baudrate: baudrate to read at from the serial port
string_length: the length of the string to read
timeout: how to long to wait for data on the port
"""
self.port = serial.Serial(port_name, baudrate=baudrate, timeout=timeout)
self.string_length = string_length
def read(self):
"""Read from self.port"""
rcv = self.port.read(self.string_length)
if not rcv:
return None
try:
# note : data from the RFID reader is in HEX. We'll return
# as int.
tag = { "raw" : rcv,
"mfr" : int(rcv[1:5], 16),
"id" : int(rcv[5:11], 16),
"chk" : int(rcv[11:13], 16)}
print "READ CARD : %s" % tag['id']
return Card(tag)
except:
return None
class Card(object):
def __init__(self, tag):
self.tag = tag
def get_id(self):
"""Return the id of the tag"""
return self.tag['id']
def get_mfr(self):
"""Return the mfr of the tag"""
return self.tag['mfr']
def get_chk(self):
"""Return the checksum of the tag"""
return self.tag['chk']
def __repr__(self):
return str(self.get_id())
def is_valid(self):
"""Uses the checksum to validate the RFID tag"""
i2 = 0
checksum = 0
for i in range(0, 5):
i2 = 2 * i
checksum ^= int(self.tag.raw[i2 + 1:i2 + 3], 16)
return checksum == tag['chk']