qrfid.py

import serial
import sys
import time


class rfid_reader() :
    @staticmethod
    def factory(t):
        if t == 'hid':
            return rfid_reader_hid()
        elif t == 'serial':
            return rfid_reader_serial()
        elif t == 'tormach':
            return rfid_reader_tormach()
        assert 0, "bad rfid type specified: " + t
    
    def initialize(self, baud_rate=None) :
        pass

    def get_card(self):
        return None

    def flush(self):
        pass

    def fileno(self):
        pass


# reads from keyboard (HID RFID reader or testing with manual input)
class rfid_reader_hid(rfid_reader) :

    def get_card(self):
        return input()

    def flush(self):
        pass

    def fileno(self):
        return sys.stdin.fileno()


# reads directly from RDM6300 RFID reader which has a simple protocol with framing and checksum
class rfid_reader_serial(rfid_reader) :
    def __init__(self) :
        pass

    def fileno(self):
        return self.UART.fileno()
    
    def initialize(self, serial_port="/dev/ttyAMA0", baud_rate=9600) :

        print('port %s %d baud' % (serial_port, baud_rate))
        self.UART = serial.Serial(serial_port, baud_rate)
        self.UART.close()
        self.UART.open()


    def flush(self) :
        self.UART.flushInput()

    def get_card(self) :
        if not self.UART.inWaiting() :
            return None

        # Reset vars
        checksum = 0
        checksum_Tag = 0
        ID = ""

        # Read chars
        buf = self.UART.read(size=1)

        # look for STX
        if buf[0] != 0x02:
            self.flush()
            return None

        done = False
        while not done:
            buf = self.UART.read(size=1)
            if buf[0] == 0x03:
                done = True
            else:
            	ID = ID + '%c' % buf[0]
            
        # Build ID
        #for Counter in range(13):
        #    buf = self.UART.read(size=1)
        #    ID = ID + '%c' % buf[0]

        # Remove ETX from string
        #ID = ID.replace("\x03", "")

        while len(ID) < 10:
            ID = '0' + ID

        print(ID)

        # Calc checksum
        for I in range(0, 9, 2):
            checksum = checksum ^ (((int(ID[I], 16)) << 4) + int(ID[I+1], 16))
        checksum = hex(checksum)
        # Find tag
        Tag = ((int(ID[1], 16)) << 8) + ((int(ID[2], 16)) << 4) + ((int(ID[3], 16)) << 0)
        Tag = hex(Tag)
        # Print data

        card = str(int(ID[4:10], 16))
        print("------------------------------------------")
        print("Data: ", ID)
        print("Tag: ", Tag)
        print("ID: ", ID[4:10], " - ", int(ID[4:10], 16))
        print("Checksum: ", checksum)
        print("------------------------------------------")


        return card


# reads from custom pendant RFID which returns STX + 10 hex digits + ETX:
# 0123456789\n\r
class rfid_reader_tormach(rfid_reader) :
    def __init__(self) :
        pass

    def fileno(self):
        return self.UART.fileno()

    def close(self):
        self.UART.close()

    def set_led(self, mode):
        self.UART.write(mode.encode('utf-8'))

    
    def initialize(self, serial_port="/dev/ttyACM0", baud_rate=9600) :
        print('port %s %d baud' % (serial_port, baud_rate))
        self.UART = serial.Serial(serial_port, baud_rate)
        self.UART.close()
        self.UART.open()

    def flush(self) :
        self.UART.reset_input_buffer()

    def get_card(self) :
        try:
            if self.UART.in_waiting < 12 :
                return None

            while self.UART.in_waiting >= 12:
                # Read chars
                buf = self.UART.read(size=1)

                # look for STX
                if buf[0] != 0x02:
                    return None

                buf = self.UART.read(size=11)
                if buf[10] != 0x03:
                    return None

                # Print data
                card = str(int(buf[4:10], 16))
                #print("------------------------------------------")
                #print("Data: ", buf)
                #print("Tag: ", buf[4:10], " = ", card)
                #print("------------------------------------------")

            #print("returning ", card)
            return card
        except serial.SerialException:
            print("serial exception")
            raise