===== Audio Injector Installation =====
[[http://www.audioinjector.net/rpi-hat|Audio Injector Stereo Soundcard]] and the [[http://www.audioinjector.net/rpi-zero|Raspberry Zero Soundcard]] by [[http://www.audioinjector.net/|Audio Injector]] are audio hats for the [[https://www.raspberrypi.org/|Raspberry Pi]]. These sound cards comes with two inputs and two outputs, plus a build in microphone.\\
----
==== Installation ====
This manual is made for an Raspberry Pi 4 running [[https://www.raspberrypi.org/downloads/raspbian/|Raspian Buster]] on it. It's also tested with a Raspberry Pi Zero running Raspian Buster.\\
After connecting the Audio Injector to the Raspberry Pi some software should be installed.\\
First you have to download the deb package from [[http://forum.audioinjector.net/viewtopic.php?f=5&t=3]]. Unpack it:
$ tar -xf audio.injector.scripts_0.1-1_all.deb.tar.gz
And install it:
$ sudo apt install ./audio.injector.scripts_0.1-1_all.deb
Change some configurations, in:
$ sudo nano /boot/config.txt
Comment out:
# dtparam=audio=on
And type in:
dtoverlay=audioinjector-wm8731-audio
ctl + o for saving, press return and ctl + x to leave.\\
Reboot your Raspberry Pi:
$ sudo reboot
----
----
==== Alsa Mixer Settings ====
[[https://github.com/Audio-Injector/stereo-and-zero]]\\
There are two reference alsa mixer files which will allow you to setup default output with either line input or microphone input :
Download:
$ wget https://github.com/Audio-Injector/stereo-and-zero/archive/master.zip
Unpack it:
$ unzip master.zip
go into the folder:
$ cd stereo-and-zero-master/audio.injector.scripts-0.1
and run:
$ alsactl --file asound.state.MIC.thru.test restore
$ alsactl --file asound.state.RCA.thru.test restore
----
==== Test ====
For the 10 kHz test follow the instructions on [[https://github.com/Audio-Injector/stereo-and-zero]].\\
Then install sox:
$ sudo apt install sox
In /home/pi/stereo-and-zero-master/ run:
$ sudo chmod 755 audioInjector-test.sh
$ ./audioInjector-test.sh
----
==== Simple Play and Record ====
Recording:\\
$ arecord -r 48000 -f S16_LE -c 2 -d 20 test.wav
Playing back:\\
$ aplay test.wav
----
==== I2S and I2C Pins ====
The following pins are used by the sound card, don't use them for anything else!\\
Beside the power (5V and 3V3) and ground (GND) the I2S bus needs the following pins:
GPIO 18 (Pin12) BIT CLOCK (BCLK);
GPIO 19 (Pin 35) IN and OUT LR CLOCK (DACLRC and ADCLRC);
GPIO 20 (Pin 38) DATA IN (ADCDAT);
GPIO 21 (Pin 40) DATA OUT (DACDAT);
And the I2C bus needs these pins:
GPIO 02 (pin 03) SDIN
GPIO 03 (pin 05) SCLK
//graphic from:
[[https://hifiduino.wordpress.com/2014/11/13/raspberry-pi-b-digital-audio/]]//\\
----
==== Links ====
[[http://www.audioinjector.net/rpi-hat]]\\
[[https://github.com/Audio-Injector/stereo-and-zero]]\\
[[https://learn.adafruit.com/adafruit-max98357-i2s-class-d-mono-amp/raspberry-pi-usage]]\\
[[https://www.richardmudhar.com/blog/2018/07/raspberry-pi-zero-audio-recording-with-the-audioinjector-hat/]]\\
----
==== License ====
This manual is made by **Wolfgang Spahn** 2020.\\
It is licensed under a [[http://creativecommons.org/licenses/by-nc-sa/4.0/"|Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License]].
----