first re-commit.

pigpio-master/EXAMPLES/Python/WIEGAND_CODE/wiegand.py

@@ -0,0 +1,135 @@
+#!/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()
+