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I have a set up with an input device (basically an Arduino nano) which I then use a Python script to read in the input, process it and send the results over OSC to a Pure Data patch.

This all works fine on my Windows laptop but I really want it to run on a Pi.

I did try on an old model B and it got nowhere but now I have a Pi3 I am hoping it should be fine. The python works fine and is processing the input etc but Pd doesn't seem to respond at all. If I check the DSP box to turn the Audio on on the main pd window I get the error ALSA input error (snd_pcm_open): No such file or directory I have searched around for that error but none of the forum posts etc are very helpful or relate tot he problem I have (ALSA seems to work and I can play sounds with it from the CLI)

Not really sure what to try next. Any ideas?

Max N
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Edwin Love
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  • Please clarify: Did you make a USB Audio Class Compliant device with an Arduino nano and you can play sounds and capture audio from it with other software, e.g. Audacity? – Max N Aug 18 '19 at 11:19
  • No, the input device is a touch sensitive flexible surface. The audio is generated by PD in response to the processed input from the python script – Edwin Love Aug 19 '19 at 15:13

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It is unclear from your question whether you require audio input/output at all. If you do not, you should not worry about the error message. You could launch Pd with the -noaudio flag and it should run fine:

pd -noaudio -open path/to/patch.pd

rdz
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  • The PD script / patch is generating audio in response to the input from the python script. When I run it it does not respond. – Edwin Love Aug 19 '19 at 15:14
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    It is possible that the fact that it is not responding to the osc messages is completely separate to the audio error but this is the only error I have so all I have to go on – Edwin Love Aug 19 '19 at 15:14
  • I think you should mark this answer as accepted since it solves the error which comes from asking for a soundcard which isn't available. Make a new question with example files python OSC and Pd receiving for that issue. – Max N Aug 19 '19 at 16:42
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    The Raspberry Pi Model 3 doesn't have audio input, so it is normal that Pd complains about not finding an ALSA sound input. You could run it with -noadc to make it not try to connect to audio input. Audio out would still work. From your description, it is still unclear whether Pd is not running (as in "frozen") or if it is not doing what you expect it to do. First, I'd check, if Pd is running at all and if you can play audio with the included test patch (Menu "media" -> "test audio and midi"). If that works, you can start troubleshooting your patch. – rdz Aug 20 '19 at 17:58