Excalibur

NFC driven media center

Cold start

$ sudo apt install libnfc-bin libnfc-examples vlc libvlc-bin libvlc-dev python3-venv pulseaudio

On some systems you might need to reboot.

Connect the NFC device. The following command should be able to open the interface:

$ nfc-list

Create the Python virtualenv:

$ python3 -m venv venv
$ source venv/bin/activate
(venv) $ pip install -r excalibur/requirements.txt

Check that the Python NFC wrapper can detect the NFC device and read different tags:

(venv) $ python3 excalibur/nfc/nfcwrapper.py

Check that the Python bindings for VLC can play media files (copy some audio files into your $HOME/Music folder):

(venv) $ python3 excalibur/player/player.py

Preparing the media database

The purpose of the database is to map a set of NFC identifiers (UID) to a set of media files so that Excalibur will play these files each time the corresponding NFC tag is detected. NFC tags do not store any Excalibur-related information: Excalibur only relies on the ability to detect a tag and to retrieve its UID. Therefore, any tag can be used.

There are two methods to fill in the database:

Method A: From a given directory

This is the simpliest way to build the media database as it only uses a regular directory in which the media files are stored. You can for example use $HOME/Public/Excalibur/ as a base directory to host media files. If shared among the network, you will be able to update the database without logging to the computer running Excalibur.

In this directory, you can create (recursively) subdirectories with the following normalized names:

<NFC_UID>_<directory_name>

Where <NFC_UID> is the UID of the NFC tag (without spaces, eg. 02391d04) and <directory_name> is an arbitrary name. For example:

$ mkdir -p $HOME/Public/Excalibur/02391d04_Lullaby_songs

Will automatically map the NFC tag 02391d04 with the $HOME/Public/Excalibur/02391d04_Lullaby_songs, hence playing all the included content when the tag is detected.

Method B: From a user-defined JSON configuration file

TODO

Running Excalibur

Quick start using method A to build the media database:

(venv) $ PYTHONPATH+=. python3 excalibur/app.py

Folder $HOME/Public/Excalibur/ is automatically loaded when starting Excalibur. To override this option and select different directories, you can use the --library option multiple times:

$ (venv) $ PYTHONPATH+=. python3 excalibur/app.py --library $HOME/Music/Excalibur/ --library /media/$USER/usbstorage/Excalibur/

By default, Excalibur runs for 30 minutes then terminates. You can modify this duration using the following parameter (in minutes):

(venv) $ PYTHONPATH+=. python3 excalibur/app.py --duration 120

You can also shuffle playlists with the --shuffle flag.

Automatic start at boot time

Starting Excalibur at startup can be achieved by editing the rc.local file:

$ sudo nano /etc/rc.local

Add the following lines, do not forget the exit 0 at the end of the file:

pulseaudio --start
bash -c 'cd /home/path/to/excalibur/ && ./start.sh --duration 120 --library /media/path/to/sound/library/' &

exit 0