gpio-buttons.py

#!/usr/bin/python
# Tested on RPi 3B+ with the official 7" touch-screen
# Confirmed running on LibreELEC 2.8.5 and can be added to .config/autostart.sh
#
import subprocess, time, sys, signal
sys.path.append('/storage/.kodi/addons/virtual.rpi-tools/lib')
try:
  import RPi.GPIO as GPIO
except ImportError:
  subprocess.call(['/usr/bin/kodi-send', '--action=InstallAddon(virtual.rpi-tools)'])
  sleep(10)
  import RPi.GPIO as GPIO

# Define GPIO pins in use:
# Button 1 (white cable) - Right most button on panel
BUTTON1 = 7
# Button 2 (yellow cable)
BUTTON2 = 11
# Button 3 (green cable)
BUTTON3 = 12
# Button 4 (blue cable)
BUTTON4 = 13
# Button 5 (brown cable) - Left most button on panel
BUTTON5 = 15
# Full path for LCD Brightness Control:
LCDPATH = "/sys/devices/platform/rpi_backlight/backlight/rpi_backlight/brightness"


class GpioButtons(object):
  """ Not so cleanly written class object to handle tactile buttons on RPi GPIO header """

  def __init__(self, volup, voldown, lcdup, lcddown, lcdtogg, lcdpath, lcddef=170):
    """ Init the required pin and LCD variables """
    # Configure which GPIO pin handles which function:
    self.volup = volup
    self.voldown = voldown
    self.lcdup = lcdup
    self.lcddown = lcddown
    self.lcdtogg = lcdtogg
    # Define the full path needed for the Britghness Control:
    self.lcdpath = lcdpath
    # Define the default brightness value
    self.lcddef = lcddef
    # To avoid weird behaviour, allow just one button press at any given time.
    self.buttonpressed = 0

  def start(self):
    """ Startup and keep running in background """
    self.setup()
    # Make a KILL signal trigger the Cleanup so the GPIO is cleaned up on kill.
    #signal.signal(signal.SIGTERM, self.cleanup())
    # Allow KeyboardInterrupt (crtl+c) to interrupt and clean the GPIO before exitting.
    try:
      while True:
        time.sleep(10)
    except KeyboardInterrupt:
      self.cleanup()

  def cleanup(self):
    """ Cleanup and exit """
    GPIO.remove_event_detect(self.volup)
    GPIO.remove_event_detect(self.voldown)
    GPIO.remove_event_detect(self.lcdup)
    GPIO.remove_event_detect(self.lcddown)
    GPIO.remove_event_detect(self.lcdtogg)
    GPIO.cleanup()
    sys.exit(0)

  def setup(self):
    """ Setup all GPIO Pins """
    GPIO.setmode(GPIO.BOARD)
    GPIO.setup(self.volup, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)
    GPIO.add_event_detect(self.volup, GPIO.FALLING, callback=self.volupcallback)
    GPIO.setup(self.voldown, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)
    GPIO.add_event_detect(self.voldown, GPIO.FALLING, callback=self.voldowncallback)
    GPIO.setup(self.lcdup, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)
    GPIO.add_event_detect(self.lcdup, GPIO.FALLING, callback=self.lcdupcallback)
    GPIO.setup(self.lcddown, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)
    GPIO.add_event_detect(self.lcddown, GPIO.FALLING, callback=self.lcddowncallback)
    GPIO.setup(self.lcdtogg, GPIO.IN, pull_up_down=GPIO.PUD_DOWN)
    GPIO.add_event_detect(self.lcdtogg, GPIO.FALLING, callback=self.lcdtoggcallback)


  def volupcallback(self, pin):
    """ Action for Volume Up button trigger """
    if self.buttonpressed == 1:
      return
    self.buttonpressed = 1
    subprocess.call(['/usr/bin/kodi-send', '--action=VolumeUp'])
    time.sleep(0.3)
    self.buttonpressed = 0

  def voldowncallback(self, pin):
    """ Action for Volume down button trigger """
    if self.buttonpressed == 1:
      return
    self.buttonpressed = 1
    subprocess.call(['/usr/bin/kodi-send', '--action=VolumeDown'])
    time.sleep(0.3)
    self.buttonpressed = 0

  def lcdupcallback(self, pin):
    """ Action for LCD Brightness Up button trigger """
    if self.buttonpressed == 1:
      return
    self.buttonpressed = 1
    with open(self.lcdpath, 'r+') as brightness:
      cur_br = int(brightness.readline())
      if cur_br <= 245:
        new_br = cur_br + 10
      else:
        new_br = 255
      print("Changed brightness up from %s to %s" % (cur_br, new_br))
      brightness.write('%d' % new_br)
    time.sleep(0.3)
    self.buttonpressed = 0

  def lcddowncallback(self, pin):
    """ Action for LCD Brightness Down button trigger """
    if self.buttonpressed == 1:
      return
    self.buttonpressed = 1
    with open(self.lcdpath, 'r+') as brightness:
      cur_br = int(brightness.readline())
      if cur_br >= 10:
        new_br = cur_br - 10
      else:
        new_br = 0
      print("Changed brightness down from %s to %s" % (cur_br, new_br))
      brightness.write('%d' % new_br)
    time.sleep(0.3)
    self.buttonpressed = 0

  def lcdtoggcallback(self, pin):
    """ Action for LCD On/Off toggle button trigger """
    if self.buttonpressed == 1:
      return
    self.buttonpressed = 1
    with open(self.lcdpath, 'r+') as brightness:
      cur_br = int(brightness.readline())
      if cur_br <= 10:
        new_br = self.lcddef
      else:
        new_br = 0
      print("Toggled brightness from %s to %s" % (cur_br, new_br))
      brightness.write('%d' % new_br)
    time.sleep(0.3)
    self.buttonpressed = 0

if __name__ == '__main__':
  monitor = GpioButtons(BUTTON1, BUTTON2, BUTTON3, BUTTON4, BUTTON5, LCDPATH)
  monitor.start()