Python code use for Raspberry Pi Intermission / Announce Device

rpi-inter-announce-03-14-14

import thread           # the usual suspects of imports
from time import sleep
import RPi.GPIO as GPIO
import pygame.mixer
import random
from sys import exit

pygame.mixer.init(44100, -16, 1, 1024)                  # set up the mixer
announceAudio = pygame.mixer.Sound("seats-1.wav")       # initially give announceAudio a value
soundChannelA = pygame.mixer.Channel(1)                 # initialize a mixer channel
soundChannelB = pygame.mixer.Channel(2)                 # initialize another mixer channel - we'll need 2

GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)
GPIO.setup(23, GPIO.IN, pull_up_down=GPIO.PUD_DOWN) # configure GPIO 23 for pushbutton in
GPIO.setup(24, GPIO.IN, pull_up_down=GPIO.PUD_DOWN) # configure GPIO 24 for pushbutton in
GPIO.setup(25, GPIO.IN, pull_up_down=GPIO.PUD_DOWN) # configure GPIO 25 for pushbutton in
GPIO.setup(18, GPIO.OUT)                            # configure GPIO 18 for a simple LED output

def do_play_music():                            # this will be the thread that will start music playback
        pygame.mixer.music.play(1)              # play music as background
        pygame.mixer.music.set_volume(0.4)      # set music sound to low volume
        sleep(3)

def music_callback(channel):                    # this is the callback function for the music playback
        if GPIO.input(23):
            music = ["auditorium-break-1.wav","auditorium-break-2.wav","auditorium-break-3.wav"]
            random.shuffle(music,random.random)         # randomly shuffle up the three music files
            pygame.mixer.music.load(music[0])           # uses the pygame music function which streams the music
            thread.start_new_thread(do_play_music, ())  # calls the music start thread
            GPIO.remove_event_detect(23)                # resets the GPIO event detect
            GPIO.add_event_detect(23, GPIO.RISING, callback=music_callback, bouncetime=300)
            sleep(1)                                    # the above line re-initializes the event detect

def do_announce():                              # the announcement thread routine
        soundChannelA.play(announceAudio)       # play the announcement

def announce_callback(channel):                 # this is the announcement callback
        if GPIO.input(24):
            global announceAudio                # had to make this variable global so that it could be passed
            seatsAudio = ["seats-1.wav","seats-2.wav","seats-3.wav"]    # to the thread routine
            random.shuffle(seatsAudio,random.random)                    # randomize the announce files
            announceAudio = pygame.mixer.Sound(seatsAudio[0])           # assign the variable to be passed to the thread
            thread.start_new_thread(do_announce, ())                    # start the playback thread
            GPIO.remove_event_detect(24)                                # reset the GPIO detect and reinitialize on next line
            GPIO.add_event_detect(24, GPIO.RISING, callback=announce_callback, bouncetime=200)
            sleep(1)

def do_fadeout():                               # the fadeout thread
        pygame.mixer.fadeout(5000)              # fade out any announcement going on
        pygame.mixer.music.fadeout(5000)        # fade out background music

def fade_callback(channel):                     # the fadeout callback routine
        if GPIO.input(25):
            thread.start_new_thread(do_fadeout, ())     # start the fadeout thread
            GPIO.remove_event_detect(25)                # reset the GPIO detect and reinitialize it on the next line
            GPIO.add_event_detect(25, GPIO.RISING, callback=fade_callback, bouncetime=200)
            sleep(1)

GPIO.add_event_detect(23, GPIO.RISING, callback=music_callback, bouncetime=300)    # these three lines set up the
GPIO.add_event_detect(24, GPIO.RISING, callback=announce_callback, bouncetime=300) # event detects for the first time
GPIO.add_event_detect(25, GPIO.RISING, callback=fade_callback, bouncetime=200)     # and assign which callback is
                                                                                   # associated with which button

while True:                             # this is the main program loop - which is just that
        try:                            # an endless loop that keep things going.
           GPIO.output(18, True)        # turn on the LED to show that the program is running.
           if pygame.mixer.get_busy():  # if at any time an announcement is going on the music channel is lowered
              pygame.mixer.music.set_volume(0.15) # lower the music volume while the announcer is on
           else:                                  # when the announcement is no longer happening - the music vol goes back up
              pygame.mixer.music.set_volume(0.4)  # raise the music volume back up after announcement is done
        except KeyboardInterrupt:
           GPIO.cleanup()
exit()