[gia_ferrari]

I just rigged up something similar: a DBUS listener for PulseAudio mic activity that publishes MQTT events to Home Assistant via discovery. No device config needed. I use hallway RGB lights to signal status ("purple = I'm in a meeting"). Quick and easy setup, I already had the RGB lights for mood lighting. Runs as a user systemd unit.

[pammf]

Would it switch the lights if you’re only listening with headphones while your camera is open?

Most of my awkward moments happened with family members casually cruising on my background while someone else had the word. Usually they can hear when I’m speaking and don’t enter the room.

[progman32]

In all my meeting software (the usual suspects running in the browser) the mic is always opened at the driver level, even if I'm muted. Perhaps it's to avoid latency when you unmute, or perhaps it's for those "you're muted" pop-ups.

[freedomben]

Yes, this and also potential permission issues. If the first time you try to talk you get prompted for microphone permissions, it can be highly disruptive

[garyfirestorm]

This sounds like a proper way to do it. Maybe I am biased for MQTT but I like your approach.

[BrandoElFollito]

And HA which supports autodiscovery. Such a great piece of software