rfid-turntable-pi.py

#!/usr/bin/env python
# -*- coding: utf8 -*-

#This is the Raspberry Pi RFID turntable developed for the Johnson County Library.
#Complete tutorial at [COMING SOON]
#Original Arduino project at https://github.com/jocolibrarymakerspace/ListenLocal-turntable-arduino

#Links
#Johnson County Library - http://jocolibrary.org/
#Johnson County Library MakerSpace - https://www.jocolibrary.org/we-recommend/listen-local
#Listen Local - https://www.jocolibrary.org/we-recommend/listen-local

#This project requires:
#- SPI-Py installed from https://github.com/lthiery/SPI-Py
#- MFRC522-python from https://github.com/mxgxw/MFRC522-python
#- VLC-python bindings from https://github.com/oaubert/python-vlc

#This code is based off of:
#- the Read.py example included with MFRC522-python
#- the VLC Python binding examples at https://wiki.videolan.org/Python_bindings

#MFRC522 RFID reader wiring
#| Name | Pin # | Pin name   |
#|------|-------|------------|  
#| SDA  | 24    | GPIO8      |
#| SCK  | 23    | GPIO11     |
#| MOSI | 19    | GPIO10     |
#| MISO | 21    | GPIO9      |
#| IRQ  | None  | None       |
#| GND  | Any   | Any Ground |
#| RST  | 22    | GPIO25     |
#| 3.3V | 1     | 3V3        |

#Next up:
#-General cleanup for redundancies
#-RFID tag detection feature

#---Code begins below this line!---

#We import the GPIO module
import RPi.GPIO as GPIO

#We import the time module
import time

#We import the MFRC522 RFID reader module. Remember to copy MFRC522.py in the same folder as the turntable script!
import MFRC522

#We import the signal library
import signal

#We import the VLC python bindings library
import vlc

#We define the program state
continue_reading = True

# We capture SIGINT for cleanup when the script is aborted
def end_read(signal,frame):
    global continue_reading
    print ("Ctrl+C captured, ending read.")
    continue_reading = False
    player.stop()   #We stop VLC
    GPIO.cleanup()  #We clean up the GPIO data

# We hook the SIGINT data
signal.signal(signal.SIGINT, end_read)

# We create an object of the MFRC522 class
MIFAREReader = MFRC522.MFRC522()

#We create an object of the VLC class
player = vlc.MediaPlayer()

#We define the VLC playlist
#Add as many tracks as you need, just make sure to respect the formatting and put in the correct path!
#We use implied continuation of the list to make it easier to read.
playlist = ['/home/pi/01.mp3',
            '/home/pi/02.mp3',
            '/home/pi/03.mp3',
            '/home/pi/04.mp3']

#Create lists to store and compare uids
uid = ()
justread = ()

# Welcome message
print "Welcome to the Listen Local RFID turntable"
print "Press Ctrl-C to stop."

# This loop keeps checking for RFID tags. If one is near it will get the UID.
while continue_reading:

    # Scan for cards
    (status,TagType) = MIFAREReader.MFRC522_Request(MIFAREReader.PICC_REQIDL)

    #If there is no tag detected
    if status == MIFAREReader.MI_NOTAG_ERR:
        print("No tag detected")
        
    #If we have a reader problem
    elif status == MIFAREReader.MI_ERR:
        print("Problem detected")

    # If a tag is found
    elif status == MIFAREReader.MI_OK:
        print("Tag detected")

        # We get the UID of the tag
        (status,uid) = MIFAREReader.MFRC522_Anticoll()

        # We print the tag UID
        #Alternatively you can display the tag UID with
        #print ("Tag UID: " str(uid[0]) + str(uid[1] + str(uid[2] + str(uid[3])
        print ("Tag UID: " +str(uid[0:4]))

        #We compare the tag's 'UID with whatever we might have just read
        if justread != uid:
            #This is where the music playing begins!
            if (uid[0]) == XXX and (uid[1]) == XXX: #Change the uid values to match your RFID tags
                player.stop()   #We stop playing any other track that might be playing
                print("I'm playing track XX!")  #We announce which track is about to be played
                player = vlc.MediaPlayer(playlist[0])   #We request the  track in the playlist list
                player.play() #We start playing the track we just loaded

            #Sample additional track playing block follows - uncomment and modify accordingly.
            #Add as many blocks as you have tracks to play.
            #elif (uid[0]) == XXX and (uid[1]) == XXX:
            #    player.stop()   #We stop playing any other track that might be playing
            #    print("I'm playing track XX!")  #We announce which track is about to be played
            #    player = vlc.MediaPlayer(playlist[X])   #We summon the corresponding track in the playlist list
            #    player.play() #We start playing the track we just loaded

            #We store the card's uid into the justread variable for comparing later
            justread = uid #We change the value of justread to store the latest tag UID we read

        else:
            print("You're already playing that track!") #We let the user know that the track is being played (And we don't try playing it from the top)
            time.sleep(5) #If the same card is still on the reader, we take a 5 seconds break before polling for RFID again. This does not interrupt the track being played.