Hi, this is my first time working with linux, so assume you are speaking to retarded monkey. I'm trying to develop a simple app that will to stuff when reciving DMX signal. I found a framework/application that does just the thing i need (OLA: https://wiki.openlighting.org/index....g_Architecture), but i have one problem. When running the OLA app and plug the device that it is supposed to work with to the USB port i get cryptic 'Premission deniad' error as shown in the following image.

The device in question is:
https://wiki.openlighting.org/index.php/DMX_USB_Pro


After reaching for help in the OLA community i was told that i probably need to add this udev rule:
https://wiki.openlighting.org/index....#Linux.2C_FTDI


I did it with touch and nano commands, i dont know if i was supposed to do it like that. But after doing it nothing changed.

Screenshots:
https://i.imgur.com/TESIQrw.png
First line says "olad -l 3", its to fire up OLA deamon. The feature of this software is that it refuses to run as a root so i cant write sudo before it. The instances of diabled are not a problem, those are plugins in the software that allow it to comunnicate with devices of the different producers. The last line is for USB Serial plugin that is supposed to work with Enttec device i have.
https://i.imgur.com/PLabZTX.png

Hey Annon Annon,

Welcome to Linux Questions.

I don't think I'll be of much help - I am unfamiliar with the tool you are trying to use (and am not a developer). However, one thing in your first picture hit me :

• Your tool seems to be trying to access the USB drive at its block device "file" (/dev/ttyUSB0) ... Unless this is how it is supposed to work, this is unusual. You would need to access the USB drive via a mount point.

I won't go any further for now - let us know if this gives you any ideas and if you need further assistance.

Cheers,

Rick

Yes, that is how it is supposed to work.

Basically the device contains a USB serial port adapter which from the posted images is using the FTDI chipset.

Typically for a regular user to be able to access a serial port device it must be a member of the dialin group.

sudo useradd -g dialin username

The easiest way "activate" the change is to logout and login as that user.

2 members found this post helpful.

it tells me that "dialin" group does not exist

however i was able to narrow the problem.
I went into /dev directory and changed ttyUSB0 file's permissions with chmod 777 command. After that the app and device started to work togather!
However, new problem is that after rebooting the PC and also after unpluging and pluging the device, the file is removed and created again with the same old permissions. How do i set up the system so each time i plug the usb device in it has sufficient permissions?

You should run
'ls -l /dev/ttyUSB0' and look to see what group owns it. On my system that would be the 'dialout' group.

You then add your user to that group
'sudo usermod -a -G dialout USERNAME' using your username.

Then log out and log back in.
Now the command 'groups' should show you as a member of the 'dialout' group and you should be able to have access to that device.

1 members found this post helpful.

Thank you, the "sudo usermod -a -G dialout username" command worked like a charm, now the app works as intended.

I got the dial part correct...