Looking for Device, "on the air/in a meeting" light

[marktheknife]

Similar discussion from last year you might be interested in:

[ON AIR] Battery powered indicator light

With my wife and I sharing and office it’s sometimes hard to know if someone is just in there using the desk vs actually on a call. It would be great if we had a way or connection a rule to our calendars to trigger a little indicator light over the office door to say when someone was in a meeting vs just in the office so the other person could be mindful about how much noise they’re making. Anyone know of an off the shelf battery powered z-wave indicator light that we could stick up over the d…