Zero Soundcard input configuration

[DoctorC]

Hello,

I just received my Zero Soundcards and attached them to mi Zero W. I managed to install the drivers following the tutorials and play some mp3 files using mpg123. The audio output through the jack works perfectly.

Now I would like to know:
- Can I use the mic on the headphones cable as input? If yes, please let me know how! If not, how to set up for a usb mic?
- I tried to run jackd following viewtopic.php?f=5&t=16 but I can't make it run.
I get:

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pi@raspberrypi:~ $ jackd -dalsa -dhw:0 -r96000
jackdmp 1.9.11
Copyright 2001-2005 Paul Davis and others.
Copyright 2004-2014 Grame.
jackdmp comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
JACK server starting in realtime mode with priority 10
self-connect-mode is "Don't restrict self connect requests"
Failed to connect to session bus for device reservation Unable to autolaunch a dbus-daemon without a $DISPLAY for X11

Audio device hw:0 cannot be acquired...
Cannot initialize driver
JackServer::Open failed with -1
Failed to open server

In my /boot/config.txt I added the overlays:

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# Enable audio (loads snd_bcm2835)
#dtparam=audio=on

# Enable UART
enable_uart=1

# enable the AudioInjector.net sound card
dtoverlay=audioinjector-wm8731-audio

# enable jackd
dtoverlay=i2s-mmap

What is wrong with it?

Thanks,
Enrico

[flatmax]

Hi there,

IF you can play audio through your device, then it is set up properly.

Lets focus on jackd for now. It seems that jackd can't find the environment variable DISPLAY. You can do one of two things to make this work.
1] Are you using ssh to log into your pi ? If so, use

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ssh -X pi@ip

and the DISPLAY environment variable should be set appropriately.
2] Set DISPLAY manually, like so :

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export DISPLAY=:0 

Now run jackd, that problem should have disappeared !

Matt

[DoctorC]

I forgot to write that I installed headless raspbian.
It seems I have to compile jackd2 to make it work in headless mode. The compilation breaks with errors, I'm still fighting with it...
Anyway is it possible to use the headphone inline mic as input?

Thanks,
Enrico

[flatmax]

Hi,
I Think it is only possible to use the headphone mic as input if you work out how to access the underlying electret microphone ... i.e. does it's audio jack have an electret microphone connector ? If so, then simply take the ground and the line which connects to the electret mic. on the headset and wire it up to the mic footprint on the zero.

Matt

[DoctorC]

So, I understand there is no connection on the board to mic line from the jack connector.
What is the best way to connect a mic on a cable (USB, line in, electret on a cable)?
Sorry to bother with those questions... I'm a software guy trying to learn some electronics...

Enrico

[flatmax]

If your Microphone is an electret microphone, then you can plug directly into the "Mic" footprint - it should work. You could get a suitable socket for the headset you are using a wire the GND and mic lines into the Mic footprint.

Matt