Build Instructions

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• 1

  Step #0 - buy raspberry pi zero

  Kidding, but for comparison i really did  started with that and configured everything i would like to have from this project on '5$' raspberry zero. So here it is

  What is missing on that images is external usb ethernet card and amp that was used in previous project. In fact i will reuse amp setup in every following configuration since amp part is equally compatible with onion, raspberrypi or orangepi configuration. Green relay module will be described later, but is essentially same relay module that i've used in prev project. But back to topic.

  Connection goes this way

  And this ends HW part. Than SW part

  1) Install pulse server

  sudo apt-get update && sudo apt-get upgrade -y 
  sudo apt-get install -y pulseaudio
  

  we need to configure system service, that is when pulseaudio is run with --system switch. Then it will load config from system.pa. Therefore we will edit this one

  sudo nano /etc/pulse/system.pa

  change this line to allow local usage for every user 

  load-module module-native-protocol-unix auth-anonymous=1

  and enable network server

  
  ### enable network server
  
  load-module module-native-protocol-tcp auth-ip-acl=127.0.0.1;192.168.1.0/24 auth-anonymous=1

  then we will create system service

  sudo nano /etc/systemd/system/pulseaudio.service
  

  and add this content 

  [Unit]
  Description=PulseAudio system server
  
  [Service]
  Type=notify
  ExecStart=/usr/bin/pulseaudio -v --daemonize=no --system --realtime --log-target=journal
  
  [Install]
  WantedBy=multi-user.target
  

   enable and start

  sudo systemctl daemon-reload && sudo systemctl start pulseaudio.service && sudo systemctl enable pulseaudio.service

   at this point you should see pulse running in processes 

  and from external device (laptop in my case) you should add this server as target

  nano ~/.config/pulse/default.pa

  add this line (change ip appropriately)

  load-module module-tunnel-sink-new server=192.168.1.85 sink_name=rpi  

  then run kill command to sertart pulse.

  pulseaudio -k

  new sink will appear 

  at this point pulse part is done

  2) Sound card and I2S configuration

  we will need to enable I2S and configure card but lucky enough our card is compatible with hifiberry-dac hat, so we only need to enable appropriate DT layer.

  sudo nano /boot/config.txt

  Edit those lines (last one is commented - not necessary but i prefer to have only one card for simplicity)

  dtparam=i2s=on
  dtoverlay=hifiberry-dac
  
  #dtparam=audio=on

  then you need to reboor your pi and find new sound card available

  aplay -l
  
  card 1: sndrpihifiberry [snd_rpi_hifiberry_dac], device 0: HifiBerry DAC HiFi pcm5102a-hifi-0
   Subdevices: 1/1
   Subdevice #0: subdevice #0
  
  

  to test sound i use this command

  speaker-test -t sine -f 2500 -c 2

  you should see beeping sound in both channels 

  3) last step is to configure relay module. and i will describe it in next instruction since it is exactly the same as for OrangePI. And this project is actualy for latter one, so let's leave something for it. 

  Next step is actually start adopting this basic setup to OrangePI Zero.

• 2

  Step #1 - Connect I2S Sabre sound card

  I started working with OrangePI Zero for the sake of price and simplicity. And immediately were struck by the fact that vendor forgot to solder I2S on the board header. In early versions this was solvable by soldering couple of resistors on the board (more details here) but in my revision this possibility was removed. Technicaly speaking the probem is that PA20/PCM0_DOUT pin is used by vendor to enable and disable WIFI module and not available for my use anymore. 

  This is from early version schematics, but since newer is not published i will work with this one

  So what i will do - i will solder out wifi power switch completely (and lose it forever, since i don't need it, but there is also an option also to enable it permanently) and add wire to  unit's solder pad.

  We are looking for tsot-5 element

  
  

  And we will find it near wifi chip

  (sorry, forgot to make 'before' photo, so this is soldered out state). Pad #3 is where we should solder PA20 header and pad #5 we should solder to +5V to enable wifi permanenty. In my case i skip last part. 

  Then other connections will look like this:

  So far that's it, relay module will be covered later.

  Next step is configure Sound Card in Armbian.

• 3

  Step #3 - Configure I2S sound card

  Since Armbian 5.30 it switched to device tree to setup device perepherials. Along with this change somehow a lot of features lost their support, therefore it is not as straightforward to enable I2S.

  I prepeared github repo to do it quickly

  So first get it from github

  git clone https://github.com/anabolyc/pcm5102a-for-armbian-orangepi-zero
  cd pcm5102a-for-armbian-orangepi-zero
  

  We need to add user overlays to enable I2S  (disabled by default) and enable sound card on that port

  sudo armbian-add-overlay i2s-sound.dts

  this will compile overlay script, put compiled file under /boot/overlay-user and add to /boot/armbianEnv.txt line

  user_overlays=i2s-sound

   You need to reboot to changes to take effect, but this will not work just yet. Problem is we are referencing to pcm5102a kernel module there, and this one is not included to armbian for some reason. Therefore we will build it on the same board using current kernel sources. So please check if you have build symlink

  $ ls -al /lib/modules/$(uname -r)/build
  lrwxrwxrwx 1 root root 36 Nov 17 13:42 /lib/modules/4.14.78-sunxi/build -> /usr/src/linux-headers-4.14.81-sunxi
  

  Iif it is missing  - just create it manually be running 

  sudo ln -s /usr/src/linux-headers-$(uname -r) /lib/modules/$(uname -r)/build

  Now you ready to build. First command produce pcm5102a.ko file among others. Second will copy it to appropriate kernel modules folder.

  make all
  sudo make install
  

  Now we ready to reboot and check if we have sound card listed

  $ aplay -l
  **** List of PLAYBACK Hardware Devices ****
  card 0: I2Smaster [I2S-master], device 0: 1c22000.i2s-pcm5102a-hifi pcm5102a-hifi-0 []
    Subdevices: 1/1
    Subdevice #0: subdevice #0
  

  Check if new module correctly loaded

  $ lsmod | grep snd_soc_pcm5102a
  
  snd_soc_pcm5102a       16384 1
  
  snd_soc_core          118784 5 sun4i_i2s,sun8i_codec_analog,snd_soc_simple_card_utils,snd_soc_pcm5102a,snd_soc_simple_card
  
  

  Note: this will work even if card is not connected, board will output to appropriate pins and it doesn't really care if someone listens or not. So now lets check if audio will produce
  

  speaker-test -t sine -f 2500 -c 2

   And finally i can hear beeping sound in both speakers. Hooray!

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