LightBurn bridge goes to sleep, needs ping to wake up

I’m using LightBurn bridge 1.0.0-RC4 (but the http://lightburnbridge/ web page says “LightBurn Bridge v1.0.0-RC3”). I flashed it on Raspberry Pi with 8 Gb on memory.
Sending data from LightBurn fails every time when done after a break of a few hours. The only workaround I know is to ping the bridge. A few packets are lost in the beginning, then the bridge starts responding. Once it happens, sending data to the laser works reliably. A few hours later, another ping is needed.
My laser is Thunder Nova 51 130W with Ruida controller. The WiFi coverage is very good, the router is within 15 feet or so.

Probably unrelated, but I know that the Raspberry Pi 3’s have issues with the wireless interface sleeping after idle periods despite being told not to in their config file

Hi Pavel,

It sounds like your network is going to sleep - this is not expected behavior. Has the image been modified in any way?

I ran my Pi 3 for a long time and it was powered up at all times… never had an issue with it.

Last week a thunderstorm got the Pi wet enough it isn’t usable. I took out the sd card, put it in the Pi 4 (2 G) and it’s been running out in the garage with no issues… same image.

Might try this thread…


The image wasn’t modified in any way (apart from adding my public SSH key for the “root” and “pi” users). However, iwconfig is showing that the power management is on for wlan0. The network is controlled by NetworkManager, so I followed the instructions to turn off power management in the NetworkManager configuration: linux - How to turn off Wireless power management permanently - Unix & Linux Stack Exchange

Things appear to be better. The “Start” button works from the first of the second attempt after boot. But the real test will be to wait for a few hours. I’ll keep you posted.

I also realized that the LightBurn bridge many not be getting enough power. I’m using a USB cable connected to the Thunder Laser to power it. I’ll try the native power cable.

I’m going to say that 99% chance this was your problem. Though, while we’ve never had issues with the power management, I’ll change the image default to turn it off for future releases.

I’m curious - How exactly was the Pi connected to the Thunder Laser? Through on onboard USB port? Directly to a 5V supply? To a USB hub of some sort?
It also could just be the cable itself. The Pi 4 draws a bit more power and poor quality cables just don’t work well.

1 Like

The USB cable was connected to the “USB stick” output on the Thunder laser. The other side of the cable was a type C connector that provides power to Raspberry Pi. I agree, not a good idea. The LightBurn bridge is working well with the new setup (proper power supply and power management off), no ping is needed, but I want to see if it wakes up after a longer pause.

I confirm I have a working solution. I had to click “Start” twice on one occasion. Most of the time, “Start” works right away.