84 lines
2.4 KiB
Python
84 lines
2.4 KiB
Python
import pigpio
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# Original code from https://github.com/alxsmora1/raspberrypi_wiegand
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class decoder:
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"""
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A class to read Wiegand codes of an arbitrary length.
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The code length and value are returned.
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"""
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def __init__(self, pi, gpio_0, gpio_1, callback, bit_timeout=6):
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"""
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Instantiate with the pi, gpio for 0 (green wire), the gpio for 1
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(white wire), the callback function, and the bit timeout in
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milliseconds which indicates the end of a code.
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The callback is passed the code length in bits and the value.
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"""
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self.pi = pi
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self.gpio_0 = gpio_0
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self.gpio_1 = gpio_1
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self.callback = callback
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self.bit_timeout = bit_timeout
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self.in_code = False
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self.pi.set_mode(gpio_0, pigpio.INPUT)
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self.pi.set_mode(gpio_1, pigpio.INPUT)
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self.pi.set_pull_up_down(gpio_0, pigpio.PUD_UP)
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self.pi.set_pull_up_down(gpio_1, pigpio.PUD_UP)
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self.cb_0 = self.pi.callback(gpio_0, pigpio.FALLING_EDGE, self._cb)
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self.cb_1 = self.pi.callback(gpio_1, pigpio.FALLING_EDGE, self._cb)
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def _cb(self, gpio, level, tick):
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"""
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Accumulate bits until both gpios 0 and 1 timeout.
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"""
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if level < pigpio.TIMEOUT:
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if self.in_code == False:
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self.bits = 1
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self.num = 0
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self.in_code = True
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self.code_timeout = 0
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self.pi.set_watchdog(self.gpio_0, self.bit_timeout)
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self.pi.set_watchdog(self.gpio_1, self.bit_timeout)
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else:
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self.bits += 1
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self.num = self.num << 1
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if gpio == self.gpio_0:
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self.code_timeout = self.code_timeout & 2 # clear gpio 0 timeout
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else:
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self.code_timeout = self.code_timeout & 1 # clear gpio 1 timeout
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self.num = self.num | 1
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else:
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if self.in_code:
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if gpio == self.gpio_0:
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self.code_timeout = self.code_timeout | 1 # timeout gpio 0
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else:
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self.code_timeout = self.code_timeout | 2 # timeout gpio 1
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if self.code_timeout == 3: # both gpios timed out
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self.pi.set_watchdog(self.gpio_0, 0)
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self.pi.set_watchdog(self.gpio_1, 0)
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self.in_code = False
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self.callback(self.bits, self.num)
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def cancel(self):
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"""
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Cancel the Wiegand decoder.
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"""
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self.cb_0.cancel()
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self.cb_1.cancel()
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