gbz_power_monitor.py 文件源码

def lowBattery(channel):
  #Checking for LED bounce for the duration of the battery Timeout
  for bounceSample in range(1, int(round(batteryTimeout / sampleRate))):
    time.sleep(sampleRate)

    if GPIO.input(batteryGPIO) is 1:
       break

  global playerFlag
  while playerFlag is 1:
    time.sleep(1)

  #If the LED is a solid condition, there will be no bounce.  Launch shutdown video and then gracefully shutdown
  if bounceSample is int(round(batteryTimeout / sampleRate)) - 1:
    playerFlag = 1
    os.system("/usr/bin/omxplayer --no-osd --layer 999999 " + shutdownVideo + " --alpha 180;")
    if GPIO.input(batteryGPIO) is 0:
      os.system("sudo shutdown -h now")
      playerFlag = 0
      sys.exit(0)

  #If the LED is a solid for more than 10% of the timeout, we know that the battery is getting low.  Launch the Low Battery alert.
  if bounceSample > int(round(batteryTimeout / sampleRate * 0.1)):
    playerFlag = 1
    os.system("/usr/bin/omxplayer --no-osd --layer 999999 " + lowalertVideo + " --alpha 160;")
    playerFlag = 0

    #Discovered a bug with the Python GPIO library and threaded events.  Need to unbind and rebind after a System Call or the program will crash
    GPIO.remove_event_detect(batteryGPIO)
    GPIO.add_event_detect(batteryGPIO, GPIO.BOTH, callback=lowBattery, bouncetime=300)

    #If we know the battery is low, we aggresively monitor the level to ensure we shutdown once the Power Timeout is exceeded.
    lowBattery(batteryGPIO)