mirror of https://github.com/joan2937/pigpio
136 lines
2.8 KiB
Python
136 lines
2.8 KiB
Python
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#!/usr/bin/env python
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import pigpio
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class decoder:
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"""Class to decode mechanical rotary encoder pulses."""
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def __init__(self, pi, gpioA, gpioB, callback):
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"""
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Instantiate the class with the pi and gpios connected to
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rotary encoder contacts A and B. The common contact
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should be connected to ground. The callback is
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called when the rotary encoder is turned. It takes
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one parameter which is +1 for clockwise and -1 for
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counterclockwise.
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EXAMPLE
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import time
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import pigpio
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import rotary_encoder
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pos = 0
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def callback(way):
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global pos
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pos += way
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print("pos={}".format(pos))
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pi = pigpio.pi()
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decoder = rotary_encoder.decoder(pi, 7, 8, callback)
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time.sleep(300)
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decoder.cancel()
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pi.stop()
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"""
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self.pi = pi
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self.gpioA = gpioA
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self.gpioB = gpioB
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self.callback = callback
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self.levA = 0
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self.levB = 0
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self.lastGpio = None
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self.pi.set_mode(gpioA, pigpio.INPUT)
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self.pi.set_mode(gpioB, pigpio.INPUT)
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self.pi.set_pull_up_down(gpioA, pigpio.PUD_UP)
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self.pi.set_pull_up_down(gpioB, pigpio.PUD_UP)
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self.cbA = self.pi.callback(gpioA, pigpio.EITHER_EDGE, self._pulse)
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self.cbB = self.pi.callback(gpioB, pigpio.EITHER_EDGE, self._pulse)
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def _pulse(self, gpio, level, tick):
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"""
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Decode the rotary encoder pulse.
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+---------+ +---------+ 0
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A | | | |
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+---------+ +---------+ +----- 1
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+---------+ +---------+ 0
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B | | | |
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----+ +---------+ +---------+ 1
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"""
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if gpio == self.gpioA:
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self.levA = level
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else:
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self.levB = level;
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if gpio != self.lastGpio: # debounce
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self.lastGpio = gpio
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if gpio == self.gpioA and level == 1:
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if self.levB == 1:
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self.callback(1)
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elif gpio == self.gpioB and level == 1:
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if self.levA == 1:
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self.callback(-1)
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def cancel(self):
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"""
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Cancel the rotary encoder decoder.
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"""
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self.cbA.cancel()
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self.cbB.cancel()
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if __name__ == "__main__":
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import time
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import pigpio
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import rotary_encoder
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pos = 0
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def callback(way):
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global pos
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pos += way
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print("pos={}".format(pos))
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pi = pigpio.pi()
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decoder = rotary_encoder.decoder(pi, 7, 8, callback)
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time.sleep(300)
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decoder.cancel()
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pi.stop()
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