62 lines
1.4 KiB
Python
62 lines
1.4 KiB
Python
'''
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Controls an LED using a GPIO pin
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'''
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import RPi.GPIO as GPIO
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import time, logging
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from threading import Event, Lock
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from exceptionThreading import ExceptionThread
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from itertools import chain
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logger = logging.getLogger(__name__)
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class Blinkenlights(ExceptionThread):
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def __init__(self, pin, cyclePeriod=2):
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self._stopper = Event()
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self._blink = Event()
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self._lock = Lock()
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self._pin = pin
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self.setCyclePeriod(cyclePeriod) #cyclePeriod is length of one blink cycle in seconds
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GPIO.setup(pin, GPIO.OUT)
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pwm = GPIO.PWM(self._pin, 60)
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def blinkLights():
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pwm.start(0)
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while not self._stopper.isSet():
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if self._blink.is_set():
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t = self._sleeptime
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for dc in chain(range(100, -1, -5), range(0, 101, 5)):
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pwm.ChangeDutyCycle(dc)
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time.sleep(t)
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else:
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pwm.ChangeDutyCycle(100)
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self._blink.wait()
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pwm.stop() # required to avoid core dumps when process terminates
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super().__init__(target=blinkLights, daemon=True)
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def start(self):
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ExceptionThread.start(self)
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logger.debug('Starting LED on pin %s', self._pin)
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def stop(self):
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if self.is_alive():
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self._stopper.set()
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self._blink.set()
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logger.debug('Stopping LED on pin %s', self._pin)
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def setCyclePeriod(self, cyclePeriod):
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with self._lock:
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self._sleeptime = cyclePeriod/20/2
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def setBlink(self, toggle):
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if toggle:
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self._blink.set()
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else:
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self._blink.clear()
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def __del__(self):
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self.stop()
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