Tot Tunes - A Music Player for Tiny Tots

Concept 🤔

Inspiration

Kids can play their favorite music or learn using advanced talking flash cards. This service (plus a few goodies) turns your linux device into a toddler DJ station.

Play 🔊🎶 👶

• Run bin/yt-import <youtube url> <keycard id> to download a youtube video, convert it to MP3 and copy it to the Tot Tunes device for playback.
• Swipe your new music card.
• Enjoy your Tot Tunes!

Develop 🎞

• npm install
• testing (requires 13012062.mp3 and 21804289.mp3 in $PWD/tunes)
  • macOS: npm test
  • other: KEYBOARD_DEVICE=<path to a stream of events> node main.js (requires play in path, with an API like play -v 0.2 music.mp3)
  • To see it running without actual events, set KEYBOARD_DEVICE to sample-data.bin. (KEYBOARD_DEVICE=sample-data.bin node main.js)
  • FIXME: Since audio playing was added, the instructions above are broken.
    • WORKAROUND: Before testing place 13012062.mp3 and 21804289.mp3 in $PWD/tunes. You'll also need an executable in your path called play which can be called like play -v 0.2 music.mp3. afplay works for macOS. A shim is available in the project bin directory, so a command like PATH=$PATH:bin KEYBOARD_DEVICE=sample-data.bin node main.js should work.

Deploy 🛳

• npm run build && npm run deploy (FIXME: server ssh host is not configurable 😬)
  • deploy script depends on a systemd service called tot-tunes.service

Example systemd Config

$ cat /etc/systemd/system/tot-tunes.service⤵️

[Unit]
Description=Tot Tunes

[Service]
User=pi
ExecStart=/usr/local/bin/tot-tunes
Type=simple
Restart=always

[Install]
WantedBy=multi-user.target

Example tot-tunes Service Script

$ cat /home/pi/tot-tunes⤵️

#!/bin/sh

KEYBOARD_DEVICE=/dev/input/by-id/usb-Sycreader_USB_Reader_08FF20150112-event-kbd
TUNES_DIRECTORY=/home/pi/tunes
/home/pi/tot-tunes

In this example the tot-tunes binary is located at /home/pi/tot-tunes.

MP3 Player

OS	Install Command
Raspbian	apt-get install sox libsox-fmt-mp3

Note: Sound on the Raspberry Pi Zero

To get the USB speaker working, I had to do quite a bit of digging. The winning combination seems to be configuring ALSA to use the usb audio interface by default and using the SoX player.