Leet linux preset

[vicquick]

So I think I am close to getting this thing working, and am already pretty excited. However, I get an error message when running SamplerBox that the ‘preset’ is not defined. I am also using a soundcard that is connected to the GPIO pins and might be causing some issues? Would these simply have to be changed in the samplerbox.py? Where and how do I define the preset?

This is the message I get:

Opened audio device #1
/home/pi/SamplerBox/samplerbox.py:374: RuntimeWarning: This channel is already in use, continuing anyway. Use GPIO.setwarnings(False) to disable warnings.
GPIO.setup(20, GPIO.IN, pull_up_down=GPIO.PUD_UP)
/home/pi/SamplerBox/samplerbox.py:375: RuntimeWarning: This channel is already in use, continuing anyway. Use GPIO.setwarnings(False) to disable warnings.
GPIO.setup(21, GPIO.IN, pull_up_down=GPIO.PUD_UP)
Exception in thread Thread-1:
Traceback (most recent call last):
File “/usr/lib/python3.7/threading.py”, line 917, in _bootstrap_inner
self.run()
File “/usr/lib/python3.7/threading.py”, line 865, in run
self._target(*self._args, **self._kwargs)
File “/home/pi/SamplerBox/samplerbox.py”, line 388, in Buttons
preset += 1
NameError: name ‘preset’ is not defined

Preset empty: 0

 

Thanks a lot in advance!

[vicquick]

Due to my soundcard already using GPIO 20,21 I could circumvent the error message by simply wiring the two switches to GPIO 16, 26. However, I still get an error message, now saying that the sound device is invalid.

Expression ‘parameters->channelCount <= maxChans’ failed in ‘src/hostapi/alsa/pa _linux_alsa.c’, line: 1514
Expression ‘ValidateParameters( outputParameters, hostApi, StreamDirection_Out ) ‘ failed in ‘src/hostapi/alsa/pa_linux_alsa.c’, line: 2825
Invalid audio device #1

 

Any clue on this?

[vicquick]

Update for anyone interested:

I added a line in  /etc/asound.conf to reduce the sample rate to 16000hz:

pcm.array {
type dsnoop
slave {
pcm “hw:wm8960soundcard”
channels 2
               rate 16000
}
ipc_key 666666
}

 

No more error messages for now at least. Only two out of the six buttons work, and I still have to find a way how to get my first sample played but will see how that works out.

[vicquick]

48000 should also work

[vicquick]

Everything is working now, after realising I actually needed to load some presets – hence the empty presets earlier.

I still only use two out of the six tact switches, but will probably discover their function sooner or later. Thanks for publishing such a nice project!

[Johan von Konow]

Hi, sry for not beeing able to help, but im glad that you figured it out anyway ;)
“Winners never quit and quitters never win”

I added the other switches for future use, like menu navigation, volume etc. If you miss a function, modify the python code. Check the BUTTONS THREAD (RASPBERRY PI GPIO), row362

 

[vicquick]

Hi Johan,

thanks for your reply! Indeed, the GPIO error came from the soundcard I have installed as a pi-hat, changed the code, wiring and all good now.

What you mention about GPIO buttons for volume and menu navigation sounds really interesting! Any info/details I can find on that? Controlling the volume by buttons would be awesome

cheers

[Author]

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