Simple audio player box for kids with RFID tags based on RaspberryPI.
The main focus is kids, but not only. It can play music, radio plays and web radio streams. The handling of the box is designed to be simple: select the audio content with prepared RFID tags and control audio volume and track number with just 4 buttons.
- RaspberryPI ZERO WH, RaspberryPI 1 Model A+ (but any RaspberryPI with 40pin header should do)
- WLAN dongle (if the RaspberryPI does not already have WIFI)
- Micro USB power supply
- SD card
- PN532 RFID reader (recommended)
- MFRC522 RFID reader (not recommended; bad experience with signal strength)
- MAX98357 I2S Class-D Mono Amplifier
- 4 or 8 Ohm speaker
- 4 push buttons
- female-female jumper wires
- soldering utilities
RaspberryPI
+------------+------------+
| GPIO PIN | PIN GPIO |
+------------+------------+
PN532.VCC <-- | PWR 3V3 1 | 2 5V PWR |
PN532.SDA <-- | 2 SDA 3 | 4 5V PWR | --> MAX98357.Vin (*)
PN532.SCL <-- | 3 SCL 5 | 6 GROUND | --> MAX98357.GND (*)
| 4 7 | 8 14 |
PN532.GND <-- | GROUND 9 | 10 15 |
| 17 11 | 12 CLK 18 | --> MAX98357.BCLK
| 27 13 | 14 GROUND | --> button volume+
| 22 15 | 16 23 | --> button volume+
RC522.3.3V <-- | PWR 3V3 17 | 18 24 | --> button volume-
RC522.MOSI <-- | 10 MOSI 19 | 20 GROUND | --> button volume-
RC522.MISO <-- | 9 MISO 21 | 22 25 | --> RC522.RST
RC522.SCK <-- | 11 SCLK 23 | 24 CE0 8 | --> RC522.SDA
RC522.GND <-- | GROUND 25 | 26 CE1 7 |
RC522.IRQ <-- | 0 27 | 28 1 |
| 5 29 | 30 GROUND | --> button next
| 6 31 | 32 12 | --> button next
| 13 33 | 34 GROUND | --> button prev
MAX98357.LRCLK <-- | 19 FS 35 | 36 16 | --> button prev
| 26 37 | 38 DIN 20 |
| GROUND 39 | 40 DOUT 21 | --> MAX98357.DIN
+------------+------------+
RFID-PN532
+-------------------------+
| _________________ |
| / _______________ \ |
RPI.09 (GND) <-- | GND \ \ |
RPI.01 (3V3) <-- | VCC | | |
RPI.03 (SDA) <-- | SDA | | |
RPI.05 (SCL) <-- | SCL _______________/ / |
| \_________________/ |
| |
+-------------------------+
RFID-RC522
+--------+----------------+
RPI.24 (CE0) <-- | SDA | ________ |
RPI.23 (SCK) <-- | SCK | / ______ \ |
RPI.19 (MOSI) <-- | MOSI | / / \ \ |
RPI.21 (MISO) <-- | MISO | | | | | |
RPI.27 (GPIO 0) <-- | IRQ | | | | | |
RPI.25 (GROUND) <-- | GND | \ \______/ / |
RPI.22 (GPIO 25) <-- | RST | \________/ |
RPI.17 (PWR 3V3) <-- | 3.3V | |
+--------+----------------+
MAX98357
+------------------+
RPI.35 (FS) <-- | LRCLK |
RPI.12 (CLK) <-- | BCLK |
RPI.40 (DOUT) <-- | DIN OUTPUT - | --> SPEAKER -
| GAIN |
| SD OUTPUT + | --> SPEAKER +
(*) RPI.6 (GROUND) <-- | GND |
(*) RPI.4 (5V PWR) <-- | Vin |
+------------------+
(*) There are some insteresting issues with the power supply of the MAX98357. The first boxes were built with the RaspberryPI 1 Model A+. The speaker only worked when it was touched. There was some problem with the voltage potentials. Connecting the MAX98357 to the power supply directly (without going through the RaspberryPI) solved the problem.
Newer boxes were built with the RaspberryPI ZERO WH. There it is the other way round. Therefore the power supply of the MAX98357 had to be taken from the pins of the RaspberryPI.
Install Raspbian on the SD card and do initial setup with raspi-config:
- change the pi user's password (RECOMMENDED)
- change the hostname (RECOMMENDED)
- setup WiFi (RECOMMENDED)
- boot into console (RECOMMENDED)
- enable SSH server (RECOMMENDED)
- enable SPI (REQUIRED)
Install additional software with apt install:
- mpd (REQUIRED)
- mpc (REQUIRED)
- libfind-lib-perl (REQUIRED)
- libterm-readkey-perl (RECOMMENDED; for assignTag.pl)
- libio-all-lwp-perl (OPTIONAL; for TTS speach synthesis)
- git (OPTIONAL; for installation from GitHub)
Configure /etc/mpd.conf and set:
music_directory /home/pi/music
playlist_directory /home/pi/playlists
metadata_to_use none
replaygain track
Follow the guide on:
sudo apt-get install libusb-dev libpcsclite-dev i2c-tools libnfc-bin libnfc-examples libnfc-pn53x-examples
The software depends on the Perl implementation of BCM2835 that itself depends on a C implementation. Both are not part of the standard Raspbian distribution.
First get the C library from https://www.airspayce.com/mikem/bcm2835/, unpack it and install the library with:
./configure
make
make check
sudo make install
Then get the Perl module from https://metacpan.org/pod/Device::BCM2835, unpack it and install the module with:
perl Makefile.PL
make
make test
sudo make install
Simply clone the Github repository into the "pi" user's home directory "/home/pi/" with
git clone https://github.com/f05fk/sepPI.git
There are different possibilities for starting the application. The most simple way is to add sepPI.sh to /etc/rc.local:
# add to /etc/rc.local for automatic start
/home/pi/sepPI/sepPI.sh
Create these directories:
- /home/pi/music
- /home/pi/playlists
- /home/pi/scripts
- /home/pi/status
Fill music with the MP3s and playlists with M3U playlists referencing relative to music.
Tags may be associated to music by creating symlinks in playlists, e.g. 11-22-33-44.m3u -> example.m3u.
The script assignTag.pl may be a useful tool to do that.
Put your scripts into the scripts directory. Examples are provided with script_*. Scripts may also be
associated with symlinks, e.g. 44-33-22-11 -> example.sh.
The status directory is used by sepPI to store the PersistentStatus data.
- https://www.nxp.com/docs/en/data-sheet/MFRC522.pdf
- http://wg8.de/wg8n1496_17n3613_Ballot_FCD14443-3.pdf
- https://tutorials-raspberrypi.de/raspberry-pi-rfid-rc522-tueroeffner-nfc/
- https://github.com/mxgxw/MFRC522-python
- https://metacpan.org/pod/Device::BCM2835
- https://github.com/miguelbalboa/rfid
- https://github.com/miguelbalboa/rfid/tree/master/src
- https://github.com/miguelbalboa/rfid/blob/master/src/MFRC522.cpp
- https://github.com/miguelbalboa/rfid/blob/master/src/MFRC522.h
- http://code.google.com/p/rpi-rc522
- https://github.com/codepope/rpi-rc522