Can't add laser, manual add ineffective, but Ubuntu knows the USB port is there

Hey. I’m running Ubuntu 20.04.2. I also have a Mac Pro, which works just fine with LightBurn, but I wanted to use an old Windows laptop running Linux for the speed.

I followed the usual method of installation I’d done on the Mac and in Windows 10. When I add the laser manually, it offers me the port “ttyUSB0”, but when I try to use any functions it says “Waiting for connection” in the console and nothing happens.

How would I know if I need to install that CH-340 driver? when I run the command “lsusb” it lists the laser as QinHeng Electronics 340, so I’m pretty sure that’s what’s going on, but I’m not an experienced enough Linux user to know whether it’s already installed or how to do it if I have to.

As a general rule it isn’t required to load drivers or modules in Linux. They handle everything cleanly.

There is some reason lightburn isn’t detecting it.

It might tell you a status if you can

 sudo dmesg | tail

that will display the last operations of the OS like plugging/unplugging a usb device.

There is also


to display what’s plugged in and sensed by Linux. If it’s not found, then you can install it

sudo apt-get update
sudo apt-get install usbutils

Good luck

Did you follow the installation instructions for Linux?

Installing Lightburn - LightBurn Software Documentation

If I had to guess, I suspect you didn’t provide user access to the serial ports with this command from the instructions:

sudo adduser $USER dialout && sudo adduser $USER tty

I did use lsusb, which is how I discovered that the computer knows it’s QinHeng, so some communication must be happening.

I’ll try the dmesg thing. I’m not a frequent Linux user, so I don’t know many commands.

I did follow the posted instructions for installing Lightburn for Linux. This falls under the “but what if it doesn’t work” column. The permissions thing, though, I will definitely give this a go.

Oops… I followed your link, and it appears I did NOT read these instructions. I gotta work on my reading comprehension skills. So thank you for providing.

That was the trick! I had to learn a few more things about Linux commands, but once I understood those, I figured out that I literally had to put “$USER” in there instead of my own username.

Great. Glad you’re up and running.

You actually should have been able to use your actual username in place of the $USER.

$USER is an environment variable that’s meant to store your username and is replaced with your actual username before it’s executed. You can check the value of $USER by typing echo $USER on a terminal. It’s possible you were using your full name vs username.

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