I use Smoothie. with smoothie you can configure a logic TTL signal which is fully on or fully off based on laser tube excitation. I have implemented this feature to my great satisfaction. I have added red led on top of the leaser head so each time the tube gets exited it turns on even without any radiation output e.g - even if i power only 1% - this led turns on fully. i did so for making it clear an invisible laser is in action and to be careful not to stick my hands where one shouldn’t.
I did that before purchasing lightburn about 6 months ago as a safety measure.
Now, - Your sign made me think this over.
I am using M106 command which turns on my fumes extractor and my air-assist before job starts and M107 for turning these off, but i never thought of using this output for turning an alert sign. as hard as it is to admit - I failed in adding 1 + 1
I will add that soon.
Thanks for sharing.