Car Installation Tutorial

This document will guide you through a method of setting up a fully functional touchscreen solution that can be mounted in your car. It uses KivyPie as the base linux distro.

Step 1: Install KivyPie

  1. Visit the download site and download the latest build of KivyPie. Note that this project needs at least Kivy v1.10.0, so download accordingly.

  2. Unzip the downloaded file and flash it to a MicroSD card. I recommend using Etcher. Boot your Pi with this card.

  3. Read the KivyPie FAQ Page to understand how you can connect to it. The latest version (as of this writing) has a new method to configure the network that doesn’t seem to be documented however. If you need wifi, do the following: #. Power down the Pi and mount the SD card on your desktop. #. Edit the file interfaces in the root of the SD card.

    1. Change the line:

      wpa-ssid pipaos

      to:

      wpa-ssid <whatever-your-ssid-is>

    2. Change the line:

      wpa-psk pipa123pass

      to:

      wpa-psk <whatever-your-passphrase-is>

    3. Save the changes, eject the SD card, put it back in the Pi and boot.

  4. Login with the credentials given in the FAQ, either with a physical keyboard or via SSH. The rest of the guide will use the default user, however if you wish to add a new user, set a password, and do everything with that it should be fine, just adjust accordingly.

  5. Run the following to give your user password-less sudo access:

    cat << EOF | sudo tee /etc/sudoers.d/$USER
  $USER ALL=(ALL:ALL) NOPASSWD:ALL
EOF

  6. You’ll need to expand your root volume to use the whole SD card. Run:

    sudo pipaos-config

    choose Expand Filesystem, hit enter a few times, let the Pi reboot, then log back in.

  7. If you don’t want the rainbow screen to show on boot, edit the file /boot/config.txt and add disable_splash=1 to the end of it.

  8. Run this to update your packages:

    sudo apt-get update

  9. Run this to give your user access to the backlight device (taken from https://github.com/linusg/rpi-backlight):

    cat <<EOF | sudo tee /etc/udev/rules.d/backlight-permissions.rules
  SUBSYSTEM=="backlight",RUN+="/bin/chmod 666 \
  /sys/class/backlight/%k/brightness /sys/class/backlight/%k/bl_power"
EOF

  10. Reboot.

Step 2: Install kmpc

  1. KivyPie mounts an extremely small tmpfs at /tmp, which interferes with pip’s ability to install things. Run the following to remount /tmp temporarily during the install process:

    sudo mkdir /root/tmp
sudo umount -l /tmp
sudo mount --bind /tmp /root/tmp

  2. As of this writing, the version of pip/setuptools on KivyPie is old. Run the following to update:

    sudo pip install --upgrade pip setuptools wheel

  3. Run the following to install kmpc and pull in the Pi-specific dependencies:

    sudo pip install kmpc[rpi]

  4. Run:

    kmpc --newconfig

    This will generate the default config file.

  5. Optional configuration tasks in ~/.kivy/config.ini:

    • If you want a mouse cursor to show up on the screen (in case you are running with a keyboard and mouse), add the following to the [modules] section:

      cursor =

    • If you don’t want a little circle to show up on the screen anywhere you touch, comment out this line in the [modules] section:

      touchring = scale=0.3,alpha=0.7,show_cursor=1

    • If you are getting duplicate clicks and/or keypresses with a physical mouse or keyboard, comment out the following line in the [input] section:

      %(name)s = probesysfs,provider=hidinput

Step 3: Set up mpd

  1. Put some mp3 files on there somewhere. I suggest a USB thumb drive for ease of use, but in a pinch you can just put them on the SD card somewhere. The path to these files will henceforth be named <musicpath>.

  2. Make sure your audio connection is working. Run amixer sset 'PCM' 0 to turn the audio volume up, then run speaker-test and listen for some output.

  3. Run the following to install mpc, as it is needed for testing and by the sync function:

    sudo apt-get -y install mpc

  4. The version of mpd in the repo as of this writing is super old and buggy, so we’re going to compile from source. Change <musicpath> in the below text to your musicpath. Here’s the commands:

    export MUSICPATH=<musicpath>
wget https://www.musicpd.org/download/mpd/0.19/mpd-0.19.21.tar.xz
tar xf mpd-0.19.21.tar.xz
cd mpd-0.19.21/
sudo apt-get -y install g++ libboost-dev libicu-dev libglib2.0-dev \
  libsqlite3-dev libmpdclient-dev libexpat1-dev \
  libid3tag0-dev libflac-dev libaudiofile-dev libmad0-dev libmp3lame-dev \
  libasound2-dev libcurl4-gnutls-dev libsystemd-daemon-dev \
  libfaad-dev libmpg123-dev libavcodec-dev libsndfile-dev libvorbis-dev \
  libavformat-dev libavutil-dev
./configure \
  --enable-werror --prefix=/usr --sysconfdir=/etc \
  --with-systemdsystemunitdir=/etc/systemd/system --enable-systemd-daemon \
  --enable-database --enable-sqlite --enable-libmpdclient --enable-expat \
  --enable-alsa --disable-oss --enable-icu --enable-glib \
  --enable-flac --enable-audiofile --enable-dsd --enable-mad --enable-id3 --enable-curl \
  --enable-mms=no --enable-smbclient=no --enable-nfs=no --enable-zlib=no --enable-bzip2=no \
  --enable-roar=no --enable-ao=no --enable-vorbis=yes --enable-wavpack=no --enable-gme=no \
  --enable-lame-encoder=no --enable-shine-encoder=no \
  --enable-twolame-encoder=no --enable-vorbis-encoder=no --enable-wave-encoder=no \
  --enable-modplug=no --enable-mpc=no --enable-mpg123=yes --enable-openal=no \
  --enable-opus=no --enable-sidplay=no --enable-shout=no --enable-adplug=no \
  --enable-sndfile=yes --enable-wildmidi=no --enable-soundcloud=no --enable-ffmpeg=yes \
  --enable-jack=no --enable-pulse=no --enable-lsr=no --enable-soxr=no --enable-fluidsynth=no \
  --enable-cdio-paranoia=no \
  --enable-recorder-output=no --enable-httpd-output=no --enable-solaris-output=no \
  --enable-libwrap=no --enable-upnp=no --enable-neighbor-plugins=no --with-zeroconf=no \
  --enable-aac
make
sudo make install
sudo useradd -M mpd
sudo usermod -L mpd
sudo usermod -G audio mpd
sudo mkdir -p /var/lib/mpd/playlists
sudo mkdir -p /var/log/mpd
sudo chown -R mpd:audio /var/lib/mpd
sudo chown -R mpd:audio /var/log/mpd
cat << EOF | sudo tee /etc/mpd.conf
music_directory         "$MUSICPATH"
playlist_directory      "/var/lib/mpd/playlists"
db_file                 "/var/lib/mpd/database"
log_file                "/var/log/mpd/mpd.log"
pid_file                "/var/lib/mpd/pid"
state_file              "/var/lib/mpd/state"
sticker_file            "/var/lib/mpd/sticker.sql"
user                    "mpd"
group                   "audio"
bind_to_address         "127.0.0.1"
max_output_buffer_size  "32768"
EOF
sudo chown -R $USER:audio "$MUSICPATH"
sudo chmod g+w "$MUSICPATH"
sudo systemctl enable mpd
sudo systemctl start mpd

  5. See https://www.musicpd.org/doc/user/config.html for further details on the /etc/mpd.conf file. You might want to add ‘replaygain’ variables, for example.

  6. Restart mpd:

    sudo systemctl restart mpd

  7. Run the following to update the mpd database:

    mpc update

  8. Edit the file ~/.kmpc/config.ini and set the musicpath variable to <musicpath>

  9. Save the file and run kmpc again. You should now be able to browse the library, add files to the playlist, and generally use the app.

Step 4: Run at Boot

The easiest way to get kmpc running at boot time is by using a systemd user unit. Run the following commands:

mkdir -p ~/.config/systemd/user

cat > ~/.config/systemd/user/kmpc.service <<EOL
[Unit]
Description=kmpc

[Service]
ExecStart=/usr/local/bin/kmpc
Restart=always

[Install]
WantedBy=default.target
EOL

systemctl --user enable kmpc
sudo loginctl enable-linger sysop # substitute your username if you used a new one

You can now start the kmpc process using systemctl --user start kmpc.

Step 5: Add Fanart (optional)

The directory structure for fanart is as follows, with <fanartpath> as the root folder:

fanartpath
├── 078a9376-3c04-4280-b7d7-b20e158f345d    # musicbrainz artistid
│   ├── __Artist Name__                     # empty file, optional
│   ├── artistbackground                    # player background images
│   │   ├── 132224.jpg                      # you can have as many
│   │   ├── 39392.jpg                       # as you want
│   │   ├── 4679.jpg                        # or none at all
│   │   ├── 4680.jpg                        # format is 1280x720 JPG
│   │   └── 7578.jpg
│   ├── logo                                # artist logo images
│   │   ├── 130819.png                      # you can have as many
│   │   ├── 45979.png                       # as you want
│   │   ├── 15469.png                       # or none at all
│   │   ├── 47981.png                       # format is transparent PNG
│   │   ├── 39562.png                       # maximum 800x310
│   │   └── 5624.png
│   └── badge                               # artist badge images
│       ├── 130819.png                      # you can have as many
│       ├── 45979.png                       # as you want
│       ├── 15469.png                       # or none at all
│       ├── 47981.png                       # format is transparent PNG
│       ├── 39562.png                       # squarish aspect ratio
│       └── 5624.png
└── 391c9402-6688-4c3d-8f3d-d320d31b4de9    # and so on
    ├── __Another Artist__
    └── logo
        └── 154355.png

Once you’ve added some art, do the following

  1. Edit the file ~/.kmpc/config.ini and change the fanartpath variable to <fanartpath>.

  2. Run:

    sudo chown -R $USER:audio <fanartpath>
sudo chmod -R g+w <fanartpath>
sudo find <fanartpath> -type d -exec chmod g+s '{}' \;
systemctl --user restart kmpc

You should now see logos and background images for the artists that have images in the fanart folder.

Step 6: Setup Sync (optional)

See the section on Using kmpcmanager to learn how the manager program interacts with the synchost. The basic gist of it is this:

  1. Have a Linux box running in your house, connected the same wifi that the car Pi will be able to connect to. This will be called the synchost.

  2. Have mpd running on it, and fully updated.

  3. Use kmpcmanager to automatically download all the fanart and manage the ratings and copy_flags for all your tracks.

  4. Edit the file ~/.kmpc/config.ini on your car Pi and change the variables in the [synchost] section. See the section on config file ~/.kmpc/config.ini for details.

  5. Run ssh-keygen and hit enter on all the defaults. This creates a public key for this user.

  6. Insert the contents of ~/.ssh/id_rsa.pub on the car Pi into the ~/.ssh/authorized_keys file on the synchost as whatever user you have set up there.

  7. Edit the file ~/.ssh/config and add the following:

    Host <synchost>                        # this should match config.ini
  User <synchost_username>             # a user on <synchost>
  StrictHostKeyChecking no

    For example, my ssh config looks like this:

    Host 192.168.1.100
  User cgraham
  StrictHostKeyChecking no

    And the synchost variable in the [sync] section in my ~/.kmpc/config.ini is set to “192.168.1.100”.

  8. Test that your connection is working by running:

    ssh <synchost>

  9. Stop the kmpc service and test the sync manually by going to the Config tab and clicking Sync:

    systemctl --user stop kmpc
kmpc

  10. If that worked well, exit kmpc and restart the service:

    systemctl --user start kmpc

Now you should be able to use the Sync button in the Config tab to automatically sync all music, fanart, and song ratings with the synchost. Note that all fanart is syncronized, not just artists in the list of files to sync.