Preparing the code – the Audio connection
Leaving the UI calisthenics for a while, I started testing the audio part of the project. That is the interface of the Edison module with my USB Audio card and what I could get at its output.
I had tested the card before,in terms of Linux connectivity and I was confident that it was working as I have been using that USB Audio dongle for over a year now in my Amateur Radio activities with a number of programs for decoding/encoding digital data and was quite happy with it. It worked under Linux and Win10 as well, so when I probed it from the Edison and saw the dongle's red led blinking, indicating that the card should be working I felt sure that everything was OK.
Well not exactly the case.
I plugged the headphone output to my amp system but no sound would be produced.
I ran my little demo from Yocto bash but again no sound.
However, the card was properly selected and the “aplay” command
aplay -D default:Device mytest.wav
would only blink the dongle's led.
I tested the dongle with my netbook under WIN10 home, still no sound.
I checked the connection from settings, no problem. The mixer would auto swap from netbook's speakers to USB dongle, but no sound.
I opened the dongle, tested the jacks and then removed them, soldering directly wires to make sure I had eliminated possible connection problems, but again nothing. I decided to recycle it.
I ordered a pair of new USB Audio cards (for backup purposes) and upon arriving yesterday, I tested them. Success. They both worked fine out of the box. And yes, this time I could hear the sound on earphones and my amp.
The dongle is Sabrent USB Audio Stereo Sound Adapter, specified to work with Win, Linux and Mac OS. Cost was really low at $ ~6.
My testing started the opposite way this time, first on my netbook and then on the Edison.
In both instances it was recognized. Under Win10, it installed some driver from the web.
On the Edison, I simply issued the command
aplay -D default:Device mytest.wav
and there was sound.
Ready to test the decoding of some WEB SDR reception now, when I have that portion of my code ready, most likely this Friday.
Meanwhile, I had to pack all my things, as the long time of my stay in Seattle is over and tomorrow I will be flying back home to Greece, where my Panasonic receiver is waiting to have its Upcyling done and where I will complete my project.
Therefore this is just a short update post, with more to come next week.
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