pigpio/EXAMPLES/Python/WIEGAND_CODE/wiegand.py

136 lines
2.9 KiB
Python
Executable File

#!/usr/bin/env python
import pigpio
class decoder:
"""
A class to read Wiegand codes of an arbitrary length.
The code length and value are returned.
EXAMPLE
#!/usr/bin/env python
import time
import pigpio
import wiegand
def callback(bits, code):
print("bits={} code={}".format(bits, code))
pi = pigpio.pi()
w = wiegand.decoder(pi, 14, 15, callback)
time.sleep(300)
w.cancel()
pi.stop()
"""
def __init__(self, pi, gpio_0, gpio_1, 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 value.
"""
self.pi = pi
self.gpio_0 = gpio_0
self.gpio_1 = gpio_1
self.callback = callback
self.bit_timeout = bit_timeout
self.in_code = False
self.pi.set_mode(gpio_0, pigpio.INPUT)
self.pi.set_mode(gpio_1, pigpio.INPUT)
self.pi.set_pull_up_down(gpio_0, pigpio.PUD_UP)
self.pi.set_pull_up_down(gpio_1, pigpio.PUD_UP)
self.cb_0 = self.pi.callback(gpio_0, pigpio.FALLING_EDGE, self._cb)
self.cb_1 = self.pi.callback(gpio_1, pigpio.FALLING_EDGE, self._cb)
def _cb(self, gpio, level, tick):
"""
Accumulate bits until both gpios 0 and 1 timeout.
"""
if level < pigpio.TIMEOUT:
if self.in_code == False:
self.bits = 1
self.num = 0
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)
else:
self.bits += 1
self.num = self.num << 1
if gpio == self.gpio_0:
self.code_timeout = self.code_timeout & 2 # clear gpio 0 timeout
else:
self.code_timeout = self.code_timeout & 1 # clear gpio 1 timeout
self.num = self.num | 1
else:
if self.in_code:
if gpio == self.gpio_0:
self.code_timeout = self.code_timeout | 1 # timeout gpio 0
else:
self.code_timeout = 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
self.callback(self.bits, self.num)
def cancel(self):
"""
Cancel the Wiegand decoder.
"""
self.cb_0.cancel()
self.cb_1.cancel()
if __name__ == "__main__":
import time
import pigpio
import wiegand
def callback(bits, value):
print("bits={} value={}".format(bits, value))
pi = pigpio.pi()
w = wiegand.decoder(pi, 14, 15, callback)
time.sleep(300)
w.cancel()
pi.stop()