verlock-door-controller/wiegand.py

#!/bin/python
import logging
from time import sleep

try:
    import pigpio
except Exception:
    pigpio = False


class Decoder:
    """
    A class to read Wiegand codes of an arbitrary length.
    """

    def __init__(self, callback, bit_timeout=5):

        """
        Instantiate with the pi, gpio for 0 (green wire), the gpio for 1
        (white wire), the callback function, and the bit timeout in
        milliseconds which indicates the end of a code.

        The callback is passed the code length in bits and the hex value.
        """
        if pigpio:
            self.pi = pigpio.pi()
        else:
            self.pi = False

        self.gpio_0 = 17
        self.gpio_1 = 18
        self.door_pin = 21
        self.button_pin = 13

        self.callback = callback

        self.bit_timeout = bit_timeout
        self.items = []
        self.in_code = False

        if self.pi:
            self.pi.set_mode(self.gpio_0, pigpio.INPUT)
            self.pi.set_mode(self.gpio_1, pigpio.INPUT)
            self.pi.set_mode(self.door_pin, pigpio.OUTPUT)
            self.pi.set_mode(self.button_pin, pigpio.INPUT)

            self.pi.set_pull_up_down(self.gpio_0, pigpio.PUD_UP)
            self.pi.set_pull_up_down(self.gpio_1, pigpio.PUD_UP)
            self.pi.set_pull_up_down(self.button_pin, pigpio.PUD_UP)

            self.cb_0 = self.pi.callback(self.gpio_0,
                                         pigpio.FALLING_EDGE,
                                         self._cb)
            self.cb_1 = self.pi.callback(self.gpio_1,
                                         pigpio.FALLING_EDGE,
                                         self._cb)
            self.button_cb_h = self.pi.callback(self.button_pin,
                                                pigpio.FALLING_EDGE,
                                                self.button_cb)

    def cut_empty(self, item):
        if item[0:8] == "00000000":
            return self.cut_empty(item[8:])
        else:
            return item

    @property
    def hex(self):
        try:
            items = self.items
            if len(self.items) == 26:
                items = self.items[1:-1]
            elif len(self.items) == 64:
                items = self.cut_empty(self.items)

            bits = []
            for i in range(len(items), 0, -8):
                bits.append(int(items[i - 8:i], 2))
            return (" ".join(map(lambda a: "%-0.2X" % ((a + 256) % 256),
                                           bits))).rstrip()

        except ValueError:
            logging.error(f"Failed to convert binary to hex: {self.items}")
            return False

        except Exception as e:
            logging.error(f"Wiegand convert error (raw: {self.items}): {e}")
            return False

    def _cb(self, gpio_pin, level, tick):

        """
        Accumulate bits until both gpios 0 and 1 timeout.
        """

        try:
            if level < pigpio.TIMEOUT:

                if self.in_code:
                    self.bits += 1
                else:
                    logging.debug(f"Wiegand data transfer start")
                    self.bits = 1
                    self.items = ""
                    self.in_code = True
                    self.code_timeout = 0
                    self.pi.set_watchdog(self.gpio_0, self.bit_timeout)
                    self.pi.set_watchdog(self.gpio_1, self.bit_timeout)

                if gpio_pin == self.gpio_0:
                    self.code_timeout &= 2
                    self.items += "1"
                else:
                    self.code_timeout &= 1
                    self.items += "0"

            else:

                if self.in_code:

                    if gpio_pin == self.gpio_0:
                        self.code_timeout |= 1  # timeout gpio 0
                    else:
                        self.code_timeout |= 2  # timeout gpio 1

                    if self.code_timeout == 3:  # both gpios timed out
                        self.pi.set_watchdog(self.gpio_0, 0)
                        self.pi.set_watchdog(self.gpio_1, 0)
                        self.in_code = False

                        if self.bits >= 26:
                            hex = self.hex
                            if hex:
                                self.callback(hex)
                        else:
                            logging.error(f"Expected 26 bits, but got {self.bits:d}: {self.items}")

        except Exception as e:
            logging.error(f"Wiegand callback error: {e}")

    def button_cb(self,  gpio_pin, level, tick):
        print(f"button: gpio_pin:{gpio_pin}, level:{level}, tick:{tick}")
        self.open_door()

    def open_door(self):
        self.pi.write(self.door_pin, 1)
        sleep(3)
        self.pi.write(self.door_pin, 0)

    def cancel(self):

        """
        Cancel the Wiegand decoder.
        """

        self.cb_0.cancel()
        self.cb_1.cancel()
        self.button_cb_h.cancel()
        self.pi.stop()