dkiefner / pixiebox

An RFID based music player

PixieBox

An RFID based music player inspired by the Phoniebox.

The Goal

The goal is to strip down the complex setup to very specific needs and requirements like:

• supports only playing local files for now
• supports only MFRC522 as an RFID scanner

Hardware

Components

• Raspberry Pi 4
• RC522 RFID reader (13.56 Mhz)
• Mifare RFID chips/tags (13.56 Mhz)

GPIO Setup

This is the GPIO pin header overview (credit to https://www.raspberrypi.com/documentation/computers/raspberry-pi.html):

Connect the Scanner

Cable	Color	Pin Number	Pin Name
Power	Red	1	3.3V Power
Ground	Black	14	Ground
MOSI	Green	19	GPIO 10 (MOSI)
MISO	Orange	21	GPIO 9 (MISO)
RST	Blue	22	GPIO 25
SCK	Light Brown	23	GPIO 11 (SCLK)
SDA	Dark Brown	24	GPIO 8 (CE0)

Connect the power button with LED

Cable	Color	Pin Number	Pin Name
Power	Red	8	GPIO 14 (TXD)
Ground	Black	6	Ground
LED	Yellow	5	GPIO 3 (SCL)
Ground	Brown	9	Ground

Setup

Raspberry Pi

When writing the Raspberry OS image

• name the user pi as this will be used in most places of the service to reference resources
• install Raspberry Pi OS based on Debian Bullseye

After installing the Raspberry OS

One needs to change the following on the new boot partition:

• create a new ssh file in the root volume: touch ssh
• create a new wpa_supplicant.conf file in the root volume: touch wpa_supplicant.conf
• add the following content to the wpa_supplicant.conf:

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
country=SE
network={
    ssid="YOUR_NETWORK_NAME"
    psk="YOUR_PASSWORD"
    key_mgmt=WPA-PSK
}
network={
    ssid="YOUR_NETWORK_NAME"
    psk="YOUR_PASSWORD"
    key_mgmt=WPA-PSK
}

General

After installing the Pi OS and booting up the Pi, the following steps are needed:

Download this repository:
One-time download:

cd; wget https://github.com/dkiefner/pixiebox/archive/refs/heads/main.zip; unzip main.zip; rm main.zip; mv pixiebox-main pixiebox

Developer version (use git pull to get updates from latest master):

cd; sudo apt install -y git; git clone https://github.com/dkiefner/pixiebox.git

Run the installation script:

chmod +x ~/pixiebox/scripts/install.sh; sudo ~/pixiebox/scripts/install.sh

Test if everything is set up correct (hint: you should hear piano music playing):

chmod +x ~/pixiebox/scripts/test-setup.sh; ~/pixiebox/scripts/test-setup.sh

Power LED

If you have an LED connected to the GPIO14 (TxD) then run the following script to enable the LED when the Pi is running:

chmod +x ~/pixiebox/scripts/enable-power-led.sh; sudo ~/pixiebox/scripts/enable-power-led.sh

Usage

Create new RFID tags with audio

To create a new RFID tag and associate audio files with it, do the following:

• copy all audio files you want to play for a given RFID tag into ~/pixiebox/data/audio/upload on the Raspberry Pi ( e.g. using scp or share the directory using Samba)
• run the following script: python3 ~/pixiebox/app/service/new_audio_tag.py and it will do the magic

Create new RFID tags with system actions

To link system actions like stopping the music to an RFID tag, run the following script:

python3 ~/pixiebox/app/service/new_system_tag.py

Run the player script and listen for RFID tags

For now, it is required to start the program manually (there will be a service setup provided soon):

python3 ~/pixiebox/app/service/pixiebox.py

This will run the PixieBox in an endless loop. To stop it, press Ctrl + C (which will kill the current running script) .

Upload audio files to the upload folder of the PixieBox

A simple tool to do the job is scp to transfer files from a Computer to the PixieBox. Here is an example to move all audio files from ~/Downloads/pixiebox-audio on a Computer to the upload folder of the PixieBox. Please replace <pi-user> with the actual username you used to set up the Raspberry Pi (usually this is pi) and <pi-ip> with the ip address of the Raspberry Pi in the local network (e.g. 192.168.0.1):

scp -r ~/Downloads/pixiebox-audio <pi-user>@<pi-ip>:~/pixiebox/data/audio/upload/

Note: It is important to use the -r parameter to move every file in a directory to its destination as all as having no / at the end of the first path. Adding a / would transfer the folder instead of all the files within that folder.

Run as a service

The PixieBox reader can be run as a service in the background. If enabled, it will also make sure the service is up and running after every restart of the Pi.

Install the service

To install and start the service as a systemd service, run the following command:

chmod +x ~/pixiebox/scripts/install-service.sh; sudo ~/pixiebox/scripts/install-service.sh

After executing the script, run the following command to check if service is up and running:

sudo systemctl status pixiebox.service

This should print something like the following:

● pixiebox.service - PixieBox music player service
     Loaded: loaded (/home/pi/pixiebox/app/service/pixiebox.service; enabled; vendor preset: enabled)
     Active: active (running) since Tue 2022-08-02 12:51:08 CEST; 6min ago
   Main PID: 1299 (python3)
      Tasks: 1 (limit: 4164)
        CPU: 6min 38.289s
     CGroup: /system.slice/pixiebox.service
             └─1299 /usr/bin/python3 /home/pi/pixiebox/app/service/pixiebox.py

The important part to look for in the output is Active: active (running).

Start and stop the service

The service can be stopped and started manually. This is needed if one want to run other scripts that want to use the RFID reader like create a new tag. Remember to start teh service again after you finished with the other script.

To stop the service run the following command:

sudo systemctl stop pixiebox.service

To start the service run:

sudo systemctl start pixiebox.service

Service logs

When running the PixieBox as a service, all stdout and stderr will be logged to the journal instead of the terminal.

To see the journal logs, run the following command:

sudo journalctl --unit=pixiebox

To see live updates of the journal, add the parameter -f to "follow" the log.

Install a system shutdown button

To use a button for turning the Raspberry Pi on and off, wire the button up on GPIO3 and GND. Turning on the Raspberry Pi will be handled by the Raspberry Pi itself, there is no more work needed. To turn the Raspberry Pi off a software solution is necessary. Even though the Raspberry PI is shutdown properly, the red light on the Raspberry Pi is still on. The red light only indicates that the Raspberry Pi is receiving enough power.

Install the service

To install and start a service that is listening for the button press, run the following command:

chmod +x ~/pixiebox/scripts/install-shutdown-button.sh; sudo ~/pixiebox/scripts/install-shutdown-button.sh

After executing the script, run the following command to check if service is up and running:

sudo systemctl status shutdown_system_with_button.service

This should print something like the following:

● shutdown_system_with_button.service - Shutdown the system on button press
     Loaded: loaded (/home/pi/pixiebox/app/service/shutdown_system_with_button.service; enabled; vendor preset: enabled)
     Active: active (running) since Fri 2022-10-21 20:57:17 CEST; 17s ago
   Main PID: 964 (python3)
      Tasks: 1 (limit: 4164)
        CPU: 61ms
     CGroup: /system.slice/shutdown_system_with_button.service
             └─964 /usr/bin/python3 -u /home/pi/pixiebox/app/service/shutdown_system_with_button.py

Oct 21 20:57:17 raspberrypi systemd[1]: Started Shutdown the system on button press.
Oct 21 20:57:17 raspberrypi python3[964]: Waiting for button press...

The important part to look for in the output is Active: active (running).

Install the Web App

The Web App simplifies some administration like attaching audio to RFID tags, creating backups or controlling the media player.

Install the service

To install and start the service that is running the Web App, run the following command:

chmod +x ~/pixiebox/scripts/install-webapp.sh; sudo ~/pixiebox/scripts/install-webapp.sh

After executing the script, run the following command to check if service is up and running:

sudo systemctl status pixiebox_webapp.service

This should print something like the following:

● pixiebox_webapp.service - Web app for PixieBox music player
     Loaded: loaded (/home/pi/pixiebox/app/web/pixiebox_webapp.service; enabled; vendor preset: enabled)
     Active: active (running) since Tue 2022-11-08 19:57:42 CET; 42s ago
   Main PID: 978 (python3)
      Tasks: 1 (limit: 4164)
        CPU: 531ms
     CGroup: /system.slice/pixiebox_webapp.service
             └─978 /usr/bin/python3 -u -m flask --app=/home/pi/pixiebox/app/web/app run --host=0.0.0.0

Nov 08 19:57:42 raspberrypi systemd[1]: Started Web app for PixieBox music player.
Nov 08 19:57:42 raspberrypi python3[978]:  * Serving Flask app '/home/pi/pixiebox/app/web/app'
Nov 08 19:57:42 raspberrypi python3[978]:  * Debug mode: off
Nov 08 19:57:42 raspberrypi python3[978]: WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead.
Nov 08 19:57:42 raspberrypi python3[978]:  * Running on all addresses (0.0.0.0)
Nov 08 19:57:42 raspberrypi python3[978]:  * Running on http://127.0.0.1:5000
Nov 08 19:57:42 raspberrypi python3[978]:  * Running on http://192.168.0.20:5000
Nov 08 19:57:42 raspberrypi python3[978]: Press CTRL+C to quit

The important part to look for in the output is Active: active (running).

The Result