I made an ON AIR sign for my wife to use in her office. I kept walking in when she was on a video call or meeting so I wired a light switch at her desk up to the sign outside the door. She can turn it on and off when she is busy.

I used a piece of thin plexi scratched with sandpaper to go behind the lettering with the O,A,R small letter pieces glued to plexi.

I bought the battery powered light switch and pulled out the leds from the case and put them in the on air box.