AirPi

Als ich mir einen Beamer zulegte, war mir nicht bewusst wie kompliziert  es sein würde, Ton von gescheiten Boxen abzuspielen.

Idee:
Ton von einem AppleTV 3 (an einem Beamer angeschlossen) über Airplay an einen Raspberry Pi Zero W schicken, der Audio Daten digital über HDMI an eine Samsung Soundbar (HW-K550/EN 3.1) weiter gibt.

Anschlüsse:
Power 5V/2A über Micro USB (OTG)
Power Eingang Raspberry Pi Zero W (More Power)
Wlan Stick an Micro USB (OTG) Daten Eingang Raspberry Pi Zero
HDMI mini auf HDMI

I. Raspberry Pi Headless WiFi Stick Setup:

We use Edimax WLan Stick (Realtek Chipsatz EW-7811Un Rasp) because driver are already installed at Raspbian.

1. Download Raspbian here…
2. HowTo install Raspbian on a SD (Mac OS) or with Etcher
3. Enable HDMI: Place this string into /boot/config.txt:
   audio_pwm_mode=2
4. There are TWO ways setting up a Pi Headless (SSH):
   1. HowTo using the wpa_supplicant.conf on the SD Card
   2. HowTo with Network over USB 

1. Headless setting up SSH using wpa_supplicant.conf (Original)

The method i used didn’t work for a long time – No Network devices found. – till i found the problem:   You have to generate an encrypted PSK Key and add this to the wpa_supplicant.conf with wpa_passphrase "YOURWIFI" "YOURPRESHAREDKEY" And / Or you can use the connection via SSH USB (OTG) Network 🙂 (More here and here)

 

2. Headless setting up SSH connection to Pi Zero W by USB (OTG)

1. Follow this.
2. Connect the Pi with your Mac (USB – Port on the Pi) and wait 90 sec.
3. Now you should see a new RNDIS/Ethernet Gadget connection
   Maybe you have to use manual IP like 169.254.64.64 / 255.255.255.0
   You should tell your computer to give the RaspberryPi connection to the internet. (Internetfreigabe)
4. When you connect to the pi the first time with ssh you may get this error: 
   warning remote host identification has changed mac !
   Remove the cached key for the IP address on the local machine:
   ssh-keygen -R raspberrypi.local
   typ in YES
5. WiFi: HowTo (and this) Headless connect to WiFi (Edimax Stick EW-7811Un):

open a Terminal:
ssh pi@raspberrypi.local

default user and password:
pi   raspberry

update the Pi:
sudo apt-get update
sudo apt-get upgrade

## Setting the network interfaces to dhcp and disable autopower-off 
open:  sudo nano /etc/network/interfaces 
paste this in the file:

auto lo
iface lo inet loopback

auto wlan0
iface eth0 inet dhcp
allow-hotplug wlan0
iface wlan0 inet dhcp
wireless-power off
wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf

## Setting the network security. I use the following settings. (FritzBox 4790 WPA2 – PSK and CCMP) (More Info):

Follow this here like here:
wpa_passphrase "YOURWIFI" "YOURPRESHAREDKEY" 

you will get:

network={
ssid="YOURWIFI"
#psk="YOURPRESHAREDKEY"
psk=39f574a95df1df0accd19ad73a4de33af0edea0f60636ff86b500c0c32caf5ca
}

write the above on the bottom in:
sudo nano /etc/wpa_supplicant/wpa_supplicant.conf
Reconfigure the interface with wpa_cli -i wlan0 reconfigure

Disconnect the Pi from your Mac and put it on  a USB Power Device.
Try to connect to The Pi. If it works: perfekt. Otherwise you have to find the right network security settings or ask an adult.

iwconfig should give you something like:

wlan0     IEEE 802.11bgn  ESSID:"YOURWIFI"  Nickname:"<WIFI@REALTEK>"
          Mode:Managed  Frequency:2.442 GHz  Access Point: 34:31:C4:E0:63:93   
          Bit Rate:150 Mb/s   Sensitivity:0/0  
          Retry:off   RTS thr:off   Fragment thr:off
          Power Management:off
          Link Quality=100/100  Signal level=70/100  Noise level=0/100
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:0  Invalid misc:0   Missed beacon:0

lo        no wireless extensions.

usb0      no wireless extensions.

 

II. Preparations for Shairport-sync:

Auto Power-Off and the Edimax WiFi WLan (Realtek Chip)
If you want to prevent the Wifi Edimax to power off automatically, you may have to add something in his driver settings:

lsmod

If we find something like 8192cu in the output we have to modify the driver settings.
Add a new file:
sudo nano /etc/modprobe.d/8192cu.conf

And add in this file:
options 8192cu rtw_power_mgnt=0 rtw_enusbss=0

reboot the Pi:
sudo reboot

AirPlay with Shairport-sync
Shairport is a great way to use your Pi as a AirPlay speaker. (no Video, no Photo)
(Also explained here and here) but the install explanation here works best. (down at Building)

Get the needed libraries:
sudo apt-get install build-essential git xmltoman
sudo apt-get install  autoconf automake libtool libdaemon-dev libpopt-dev libconfig-dev
sudo apt-get install libasound2-dev
sudo apt-get install libpulse-dev
sudo apt-get install avahi-daemon libavahi-client-dev
sudo apt-get install libssl-dev
sudo apt-get install libsoxr-dev

Download Shairport from github:
cd /tmp && git clone https://github.com/mikebrady/shairport-sync.git
&& cd shairport-sync


configurate all:
autoreconf -i -f
if you get autoreconf command not found you may install autoconf again by: sudo apt-get install dh-autoreconf


next:
./configure --sysconfdir=/etc --with-alsa --with-pa --with-avahi --with-ssl=openssl --with-metadata  --with-systemd

you have to reinstall and update all missing libraries  – should work than 🙂
next:
make

install:
sudo make install

Output should look like this:
Bla Bla Bla
Configure successful. You may now build with 'make'

everything is fin so we can install:
make
sudo make install

change folder and copy scripts:

 

creating a user named shairport in the group audio:
getent group shairport-sync &>/dev/null || sudo groupadd -r shairport-sync >/dev/null && getent passwd shairport-sync &> /dev/null || sudo useradd -r -M -g shairport-sync -s /usr/bin/nologin -G audio shairport-sync >/dev/null

now we have to change the shairport settings:

sudo nano /etc/shairport-sync.conf

like this:

general =
{
  name = "Front Room";
  password = "secret";
  interpolation = "soxr";
  // ... other general settings
};

register the scripts and reboot:
sudo update-rc.d shairport defaults
sudo reboot

now everything should work fine.
(You may have to say alsamixer that hdmi is used as audio out)