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by sporex
Fri May 31, 2019 6:18 pm
Forum: General discussion
Topic: Acoustic Echo cancellation for Raspberry Pi
Replies: 6
Views: 1109

Re: Acoustic Echo cancellation for Raspberry Pi

I can recommend the MT102 board as a hardware solution. See www.phnxaudio.com It can be connected to the USB ports and is detected as a USB ALSA device by raspbian. To make it work correctly, certain limitations on sampling rate have to be respected (16000Hz). It performs AEC, background noise supre...
by sporex
Tue Nov 27, 2018 11:16 am
Forum: Troubleshooting
Topic: phantom USB stick
Replies: 3
Views: 199

Re: phantom USB stick

/media/USB must exist in order for a mount in /etc/fstab to work. A mount point is just a directory somewhere in the filesystem. Assuming permissions don't prevent it, you can write to /media/USB/foo when nothing is mounted there. In this case writes (and reads) are from whatever filesyatem and stor...
by sporex
Mon Nov 26, 2018 5:29 pm
Forum: Troubleshooting
Topic: phantom USB stick
Replies: 3
Views: 199

phantom USB stick

I have a headless Jessie Image (SD-card = read-only) that I want to distribute to 40 units. The image is running a apache2 server and a SW that writes HTML data to a mounted USB stick. The USB is mounted at boot in /etc/fstab with the following command: LABEL=PINGLOG /media/USB vfat utf8,uid=www-dat...
by sporex
Fri Jul 20, 2018 5:28 pm
Forum: Raspbian
Topic: one hw-resource for multiple processes : Raspbian
Replies: 0
Views: 123

one hw-resource for multiple processes : Raspbian

Sorry if this is a beginners question : is it possible to use a single HW resource for multiple processes? To be more precise : I'am streaming the microphone input of a USB sound card (ALSA) to a distant IP adress (RTP/UDP). This is already existing. So this is the process that has taken the ALSA ca...
by sporex
Mon Jun 25, 2018 1:16 pm
Forum: Graphics, sound and multimedia
Topic: Audio Stream Low Latency
Replies: 12
Views: 8275

Re: Audio Stream Low Latency

Try this Regards Jakobsen 1. Make sure you compile against this implementation / version of ortp ortp-0.22.0.tar.gz Get it from here : http://download.savannah.nongnu.org/releases/linphone/ortp/sources/ 2. I changed the opus encoder / decoder to int16 from float - due to my audio devices was simple...
by sporex
Thu Jan 25, 2018 11:57 am
Forum: Raspbian
Topic: manual reset UART
Replies: 0
Views: 241

manual reset UART

Hello, I am debugging a program (FreePascal) that connects to the serial port. The trouble is, that when I stop debugging, the serial port remains in the "connected state" and is unusable for any subsequent debugging session. Thus I have to reboot the RPi any time, before starting a new session. Doe...
by sporex
Mon Oct 16, 2017 7:46 am
Forum: Graphics, sound and multimedia
Topic: usb card gets hot
Replies: 5
Views: 1154

Re: usb card gets hot

I had the same problem and I found out that the 3.5mm output jack must NOT be directly connected to any ground! Hope this will resolve the problem.
by sporex
Thu Jan 19, 2017 9:27 am
Forum: Troubleshooting
Topic: Turning off Raspberry PI without proper shutdown
Replies: 19
Views: 23142

Re: Turning off Raspberry PI without proper shutdown

So I assume using a RPi3 and boot it via network, can NOT be a solution in this case? Could be a solution, but would not be the optimal one, as there are chances that the network is not entirely available at boot of the device. (LAN segments are spread over a number of microwave links) In the past ...
by sporex
Wed Jan 18, 2017 4:26 pm
Forum: Troubleshooting
Topic: Turning off Raspberry PI without proper shutdown
Replies: 19
Views: 23142

Re: Turning off Raspberry PI without proper shutdown

This is an interesting problem. I have never done this but I do have an idea which I think could work. The idea would be to create a ram drive in memory (ramfs) which you transfer a system to. You then chroot that as the main drive and then unmount the SD card ext4 partition. Do all that at boot ti...
by sporex
Sun Oct 16, 2016 2:12 pm
Forum: Other projects
Topic: Audiolink Project
Replies: 26
Views: 17821

Re: Audiolink Project

What is "aplay -l" showing you?

Next try "speaker-test -D plughw:1,0 ...."
by sporex
Sat Oct 15, 2016 7:03 pm
Forum: Other projects
Topic: Audiolink Project
Replies: 26
Views: 17821

Re: Audiolink Project

snd_pcm_open: No such file or directory I would argue, you used the wrong audio device. In my case, I have two USB sound adapters connected: (card0 and card1) Type aplay -l card 0: Set_1 [C-Media USB Headphone Set], device 0: USB Audio [USB Audio] Subdevices: 0/1 Subdevice #0: subdevice #0 card 1: S...
by sporex
Thu Sep 01, 2016 5:01 pm
Forum: Other projects
Topic: Audiolink Project
Replies: 26
Views: 17821

Re: Audiolink Project

The only flaw is that voice becomes unintelligible after some hours and tx must be restarted.
I have to add some corrections: I apparently compiled the 2012 version of TRX.
Now, after downloading and compiling the 2014 source code, the problem is solved.
by sporex
Wed Aug 31, 2016 11:41 am
Forum: General discussion
Topic: trx won't make: alsa libraries not found
Replies: 3
Views: 885

Re: trx won't make: alsa libraries not found

1.) apt-get install libopus-dev libortp-dev
2.) make
by sporex
Fri Aug 26, 2016 1:05 pm
Forum: Other projects
Topic: Audiolink Project
Replies: 26
Views: 17821

Re: Audiolink Project

Does anybody has done this with two raspberries? Yes. I am presently running a setup with two raspberries, each one running tx and rx (by Mark Hills) It provides a full duplex voice channel with very low latency. Only thing to observe: the rx part has to be launched before the tx part on the other ...
by sporex
Thu Jan 23, 2014 5:48 pm
Forum: For sale
Topic: 3.2" TFT LCD + touchscreen + five buttons
Replies: 101
Views: 78497

Re: 3.2" TFT LCD + touchscreen + five buttons

Syspro: resolution can not be changed, you will have to setup XWindows to fit the screen. I suggest you do this on a big screen which is connected to HDMI. Make everything (icons, fonts,...) as small as possible and then check the result on LCD-PI32. I have observed the same effect that Syspro has ...

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