Please check my optimized video:   • How to Make Mach 3 buttons to Illumin...  

Illuminated buttons for Mach3, using arcade type illuminated switches to activate the main functions to run your CNC, I built this cool control panel based on a design from: Eddie Zarick
   • DIY Dedicated Mach3 CNC Control Panel  
about 2 years ago. I kind of wanted to have an emergency stop light flashing if the machine would stopped for any reason, but I did not know how to make it happen, not until I watched a video posted by CNC4XR7:    • Mach 3  Brain How to Create a Stack l...  
where I learned about macros and brains.
So, I started to rewire my control panel to accommodate the illuminated switches, the only problem that I had, was that when it was time to activate the estop led, all outputs got shut dawn by mach3, I tried every way possible to make it turn on, but I was unsuccessful, then I decided to make a timer circuit and make the button illuminate that way, which solved the problem that way. I think it turned out good, so maybe it would inspire somebody out there to make something similar. It may be a better way to do this, if you know please let me know in the comments.
I hope you like it.
Thanks for watching!!!