Show HN: I built a "Do not disturb" Device for my home office

Summary

I live with my parents and work from home. I have a nice (makeshift) office room but a lot of times my mother asks me if she can come in the room for reasons I won't get into. This is a story of how I made a custom device to let anyone know if I'm busy with a meeting or not, when it ends and a lot more. This ends with me designing a custom binary protocol that has only one user in the world. The finished device sitting deployed next to small plant Why not just share your calendar? Cool idea! And I totally tried that. Except: The Phone Issue: My mother doesn't always have her phone with her. Half the time she doesn't realize she's getting a call because the phone is buried under three pillows in another room. The "Surprise" Meetings: Not everything is on the calendar. Think of all those "Quick Sync" Slack huddles that turn into 45-minute debugging sessions. The Human Factor: Sometimes she needs to enter the room. In those cases, I turn my camera off momentarily. I needed a way to convey that specific state, "I'm here, but you can't see me." Information Overload: I didn't just want a red light. I wanted to convey when the meeting would be over, how much time is left, and maybe the current stock price of NVIDIA (okay, maybe not that last one). ESP32 and The Art of Boredom I had an ESP32 lying around from a previous project which I didn't complete (I call it "iterative abandonment," others call it "laziness"). I was also incredibly bored. Thinking about what I could do, I came up with a simple idea: Use the ESP32 to show a status on a screen based on whether my MacBook camera is ON or OFF. Sounds simple, right? The ESP connects to home WiFi, runs a check against a server on my MacBook, and boom; privacy. Figuring out how big I want the text to be Apple is... Overprotective One does not simply get the camera status on a MacBook. Even though Apple has that green hardware privacy dot, there isn't a native public API or a simple CLI tool to just ask, "Hey, is the camera on?...