This project is a very simple audiobook reader designed to be used by a kid with a single user interface:
- You put the NFC tag on the reader, it starts playing the audiobook.
- You take the NFC tag off the reader, it stops playing the audiobook.
- For simplicity, the reader does not have any buttons or other controls.
- The reader does not have a display or remember the last position in the audiobook. Happy to receive PRs for this feature.
It is designed to be used with a Raspberry Pi and a NFC reader. The NFC reader is used to select the book to read. I use a ACR122U reader. The book is read from an m3u playlist and played using the VLC player in a headless mode. The sound is played through the 3.5mm audio jack.
Regarding the cards, please take note to use NFC215 cards. These are the only ones that work with the ACR122U reader. I use the cards with NTAG215 chip from Amazon.
We are starting from a fresh install of Raspberry OS. My test device was a 4GB Raspberry Pi 4.
sudo apt update
sudo apt upgrade
git clone https://github.com/felixhammerl/bookworm.git
cd bookworm- make:
sudo apt install make - git:
sudo apt install git - pyenv:
curl https://pyenv.run | bash - poetry:
curl -sSL https://install.python-poetry.org | python3 - - VLC:
sudo apt install vlc
Please note that pyenv and poetry require a restart of the shell to be available. Also, this needs to be added to the .bashrc file:
export PYENV_ROOT="$HOME/.pyenv"
[[ -d $PYENV_ROOT/bin ]] && export PATH="$PYENV_ROOT/bin:$PATH"
eval "$(pyenv init - bash)"
export PATH="/home/pi/.local/bin:$PATH"Once this is done, you can install the python dependencies:
make installThis should install the required Python dependencies.
In order to use the NFC reader, we need to give a non-root user access to the device. This is done by adding a rule to the udev system.
poetry run python -m nfcThere should be an output along the lines of:
This is the 1.0.4 version of nfcpy run in Python 3.12.9
on Linux-6.6.74+rpt-rpi-v8-aarch64-with-glibc2.36
I'm now searching your system for contactless devices
** found ACS ACR122U PN532v1.6 at usb:001:007
I'm not trying serial devices because you haven't told me
-- add the option '--search-tty' to have me looking
-- but beware that this may break other serial devs
This means that the device is found. Remember the USB path, in this case usb:001:007.
Now we need to add a rule to the udev system to give access to the device. First, we need to find out the device's USB vendor and device IDs. This can be done with the following command:
lsusbThis should give an output like this:
Bus 001 Device 011: ID 072f:2200 Advanced Card Systems, Ltd ACR122U
Remember the 072f:2200 part, just be aware that your values may be different! This is the first part is the vendor ID and the second the device ID. We need to add this to the udev rules.
The following commands should do the trick:
sudo sh -c 'echo SUBSYSTEM==\"usb\", ACTION==\"add\", ATTRS{idVendor}==\"072f\", ATTRS{idProduct}==\"2200\", GROUP=\"plugdev\" >> /etc/udev/rules.d/nfcdev.rules'
sudo udevadm control -RThis should give the user access to the device. You can check this by running the poetry run python -m nfc command again. If the device is found, everything is set up correctly.
nfcpy is not able to communicate with Mifare cards. This is because Mifare cards are not NFC compliant. They are based on the ISO 14443 standard, but they are not fully compliant with it. Make sure you understand this caveat when ordering your cards!
They playlists for the audio books are simple m3u files. Put your MP3 and your m3u files on a USB stick. The m3u file should contain the path to the MP3 files. The MP3 files should be in the same directory as the m3u file.
In order to make sure that your MP3 files are in the correct path, you can figure out the device and edit /etc/fstab to mount the device at the correct path. First, get the device identifier via lsblk (to identify the device) and blkid (to get the UUID). Then, add the device to the /etc/fstab file. Here is an example:
UUID=B11B-1E14 /mnt/usb0 vfat defaults,auto,users,rw,nofail,umask=000 0 0
Please be careful when editing the /etc/fstab file. Incorrect entries can lead to a non-bootable system.
I use NFC Tools for macOS and Android to write the NFC tags. The tags should contain a single NDEF entry with a file URI, pointing to the m3u playlist file.
To start it manually, run:
poetry run python -m bookwormTo start it automatically upon device start, add it as a systemd service:
sudo cp bookworm.service /etc/systemd/system/bookworm.service
sudo systemctl daemon-reload
sudo systemctl start bookworm
sudo systemctl enable bookwormThat's it! You should now be able to scan your NFC tags and listen to your audiobooks.
If you're as clueless as I am about NFC, here are some notes that might help you understand the NFC reader a bit better.
nfcpy is a Python library that allows you to interact with NFC devices. In order to scan for a card, you can specify targets. The brty parameter is a shorthand for "bitrate and type", tuple with two values. The first value is the bitrate in kbit/s (e.g. 106 for NTAG215 chips) and the second value is the NFC type (e.g. NFC type A for NTAG215 chips). The bitrate is an integer and the NFC type is a string. The NFC type can be A, B, or F.
See: https://www.rfwireless-world.com/Terminology/NFC-A-vs-NFC-B-vs-NFC-F.html
The signalling type NFC-A is based on ISO/IEC 14443A. It is similar to RFID type A. In the type-A based communication delay encoding (miller encoding) technique is employed along with AM modulation. Here binary data is transmitted with the data rate of about 106 Kbps using type A communication. Here binary signal must change from 0 % to 100 % to distinguish between binary 1 and binary 0 data informations.
The signalling type NFC-B is based on ISO/IEC 14443B. It is similar to RFID type B. Here manchester encoding technique is employed. Here instead of 100%, AM modulationat 10% is used. This convention is used to distinguish between binary 1 and 0. 10% change from 90% for binay 0 (i.e. low) and 100% for binary 1 ( i.e high) is used. In manchester coding zero cross over happens in the bit period used to represent both 0 and 1. Here a low to high transition represents binary 0 bit and high to low transition represents binary 1 bit. It is recommended to have the zero cross over in the middle of the bit period.
The signalling type NFC-F is based on FeliCA JIS X6319-4. It is the faster form of RFID communication. It is alse known as FeliCa. It is the technology most popularly used in Japan. It is used for variety of applications such as creadit card or debit card based payments, subway ticketing for access control to the trains, personal identification at the office and residential flats etc.