Show HN: I’ve built an IoT device to let my family know when I’m in a meeting | Hacker News Reader

Show HN: I’ve built an IoT device to let my family know when I’m in a meeting

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121 pointsmococa78 comments

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.

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

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

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.

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.

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

Mine is even simpler - I just control an off-the-shelf smart bulb via a couple of macOS Shortcuts, which is trivial using Homekit. Those are driven by Hammerspoon which triggers the shortcuts based on the camera events. No custom hardware and like 20 lines of code (not including the shortcuts, I guess). I have the bulb in a normal lamp base outside my door. It's properly event driven rather than polling, too.

Similar - Hammerspoon detects whether I have a Teams meeting window open (I never have my camera on) and calls out to Home Assistant to control a WLED strip visible outside the room. Also have a Zigbee button for ad-hoc control if I'm called into a Slack huddle, etc.

(I've also got it parsing my Outlook iCal to do "meeting pending", "meeting maybe pending" but it turns out that Outlook's iCal is nonsense and parsing it is a fool's errand.)

The custom hardware is the apple device and the smart bulb. Homekit doesn't appear to be usable outside that ecosystem, so I wouldn't call it non-custom

Is there any way to do this with a bulb near you if you use multiple rooms? Like using closest Bluetooth range or something?

Triggering based on the webcam is very smart.

I can think of at least 5 different companies that have tried to launch similar products, including a couple local startups. Most of them had some sort of manual control which everyone gets tired of after a couple days. The few people I saw try to use the manual lights would forget to turn it off, which turned it into a false alarm system, which quickly taught everyone to ignore it and peek their head in anyway because it was on so frequently that everyone knew it had no actual correlation with the person being in a meeting.

I use a StreamDeck with MuteDeck (which basically provides a consistent tooling for the buttons regardless of Teams/Zoom/Meet).

MuteDeck can also integrate with hardware tools, specifically the Plenom Busylight (https://busylight.com/), which actually got a lot more reasonable price-wise from my memory ($50). They have a couple of different types of light mount.

But for now I'm fine - I work from home, desk is in the middle of the room facing the door (so camera is aimed at me and far wall). If my partner walks in, she can see the camera status on my Insta 360 camera on my monitor which has a green light visible from any direction if the webcam is live.

I've considered doing something like this a few times, this is seriously ripe for an ON AIR sign :D

If I ever find myself in your town I'm going to get free wifi.

But seriously I've wanted to build something like this for so long just never had the time. Going to definitely do it now. Love the idea of using the camera status to change the light.

That leak was intentional. ;-)

Come over to my place for some beers.

A great alternative to https://busy.bar/ if all you want is the core functionality, not bells and whistles, for the 10% of the price.

thx for the reference, though i think the bells and whistles may have been the point.

Indeed! Market segmentation ftw ;)

It says $250 (but of course, pretty cool). Esp module is probably <$10. What am I missing?

Edit: misread parent, ignore.

https://busylight.com/ can tie in to things like MuteDeck/Streamdeck which I use, for $50.

I did the same a few years ago with a Mac in swift -- listens to the event log via some private ObjC API for camera on and off, and checks for microphones in use. Homekit LED over door turns green if computer is awake/unlocked and not idle more than some threshold. Turns yellow if a physical mic is in use. Turns red if a camera is in use. It sends an indirect request to HomeKit to turn on/off or set the color of the light. (Indirect, because I directly set values on a homebridge synthetic accessory, and use homekit rules to mirror those changes to the actual light, which feels hacky -- talking to homekit directly looked too complicated and entitlement heavy.)

It's worked like a champ. -- although every few major macOS releases, Apple changes the log string for camera on and off events.

I like the ingenuity, but I didn’t want have to build custom hardware. My solution:

Lutron smart plug

“On Air” sign off of Etsy

Script to watch log file indicating the state of my webcam. On changes, triggers an Apple Home command to turn the Lutron switch off and on.

You should write about it and add pictures! :)

What happens if you turn off your video? For large or long meetings, I generally turn my camera off.

Lots of haters today. Love it, great opportunity to build something that solves a problem for you for cheap and gives you an opportunity to play with some tech.

This is very cool and I'm glad you were able to build it.

On the contrary though, I've been fascinated with simple non-technical solutions to problems lately. For example, my buddy hates it when people use his driveway to turn around. He lives on a corner lot and the layout is prone to people turning around in his driveway, and apparently this is a pet peeve of his. He was talking about installing a gate, or a retractable pole that he could extend from a hole in the driveway, all these intricate technological solutions, etc. I gave it some thought and got him a street cone off eBay to put in his driveway. I leveraged human psychology over technology and it worked like a charm and only cost $30.

For your example, I would just put a do not disturb sign on the door. The flip around kind they have at hotels. It takes getting up, but just as effective and you get a few steps in. Of course you don't get to learn and build stuff, but like I said, I'm fascinated by simple solutions right now.

But you have to remember every time to flip it before a meeting starts and after it ends. If you don’t then it will start being ignored because its never accurate. It also doesn’t work if you get an impromptu call or meeting you weren’t planning for. If you have a simple, predictable meeting schedule, a sign could be fine, but an automatic solution can work a lot better in other situations.

>But you have to remember every time to flip it before a meeting starts and after it ends.

Agree, but it's an easy habit to pick up.

>If you don’t then it will start being ignored because its never accurate.

Yes, that pavlovian response works both ways. If people keep interrupting my meetings, I'll remember to put up the thing. Remembering to take it down when the meeting is over is more problematic though.

>It also doesn’t work if you get an impromptu call or meeting you weren’t planning for.

It does. I've never had a meeting where it didn't take me a few rings to get my AirPods in anyway.

I totally agree with most of what you said and I appreciate the technical solution presented. Like I said my mind is just into finding simple, non-tech solutions right now. Also another benefit of the simple solution is it costs probably a buck or two, cheaper if I made the tag myself with scissors, part of a cardboard box and a marker.

The problem with both solutions is it doesn't work for dogs who typically can't read. An even simpler solution just occurred to me. Shut the door when I'm in a meeting.

Source code https://github.com/skhaz/onair

It was hard to notice. It's the small rectangle under the screen.

> This endpoint receives a JSON payload with a status of “on” or “off”, and turns the LED panel red or blue accordingly

Love it, I was expecting for some reason you routed a cable to the Webcam LED, or at least a light sensor (though that would make the lid unable to work if it's a laptop). But this is even more elegant, I guess I've been trying to do more hardware hacking recently and I read ESP32 so my expectations were off.

Nice! I built the same thing a few years ago: https://github.com/davidventura/on-air

It supports mac & Linux, and gets sent to an ESP32

People are discussing the reliability of the solution as if it was a life sustaining device embedded in your body behind hard to reach organs.

This is a fuck off sign people, a very cool fuck off sign and that's all!

Nice work.

I have wanted a small LED light / edge strip on top of a laptop screen that lights up when --

you are in a meeting

your microphone is on

your camera is on

customizable to work how you want (including setting it to "show" busy at will)

different color LED to mean different things if possible

This will serve to indictae to people around you whether they can interrupt you or pass in front of your screen etc.

It will also warn you the user when mic/camera is accidentally (or sneakily) on

There was a time I worked from the corner of our living room.My partner would often walk in during meetings, sometimes asking loudly where the charger was. One day, I left a sticky note on the table:“In a meeting – please check back in 30 minutes.”Surprisingly, it worked. What really changed things wasn’t the note itself, but the quiet agreement it created.

I built a similar thing using Bluetooth to a ESP32.

The hard part is reliably detecting camera status. I’m currently using a utility called Oversight, but it is event-based and the dodginess of the Bluetooth connection means the device gets out of sync.

The python script takes a different approach, so I’m going to check that out.

Neat little project. For these things, I usually find that simpler is better - use the minimum feature set to finish it and start use.

I recently found a server status bezel and was thinking of making a remote status indicator out of it... maybe I should reduce the features of that project too.

A “Do Not Disturb” door hanger costs $7 on Amazon.

And requires me to remember to get up and hang it before a scheduled meeting. Or not hang it when someone calls me and a meeting erupts. And I need to remember to take it down after each call. (If I don’t, then it’s just up all the time and might be taken as seriously as a Prop 65 Warning.)

Automations are really nice for certain things!

And I'm sure you've set up all the systems that make sure the complicated system is actually working and not dead weight or doing something unintended.

Versus, I dunno a door lock

sir, this is hacker news

obviously you need a remote motor that spins the sign to "do not disturb" when the meeting starts and then back around when it's over. and a sensor to verify it's in the correct orientation.

so you get the simplicity of the sign with the automation desired by the OP.

A webcam in the corridor that shows your office door from the outside, machine vision reads the image to know which orientation the sign is in. If a meeting begins and the sign is wrong, a little LED on the desk starts flashing red.

An alternative would be to spin the sign constantly around its center of mass while a meeting is in progress.

The meeting state coheres when the sign is observed.

nice! a clear application of quantum computing if i've ever heard one!

> Versus, I dunno a door lock

They just explained why a door lock has absolutely abysmal reliability.

"Making sure" the complicated system works significantly better than a door lock is actually really easy to do, because the door lock is so bad.

Which is more expensive than an esp32 and a led panel, and less convenient.

A "Do not disturb" sign costs roughly zero with a pen and a piece of paper.

Also, I have no idea how out of touch you have to be to claim that a simple sign that costs a few bucks is less convenient than something that requires power, another peripheral that requires power, and network access.

Fortunately my home office has an abundance of both power and network access (especially compared to the scarce resource of human attention!)

Why insist on being so negative? It's a cool little project. Just keep scrolling if it's not for you.

Exactly! Do these things not bring people joy in the drudgery of routine solutions?!

> Also, I have no idea how out of touch you have to be to claim that a simple sign that costs a few bucks is less convenient than something that requires power, another peripheral that requires power, and network access.

If you go ask random people whether they'd rather update a sign several times a day, or plug it in and be done for a year, what do you think they'd answer?

> or plug it in and be done for a year

Until the network goes down or an element of the hardware fails, or you move and need to set it up again, or…

People liked the idea of smart homes, too, but they remain niche because you need the money or technical know-how to fix them when they fall over.

Well I didn't say be done forever, I said a year. I think that covers hardware failure and moving just fine.

If the network goes down, you're not in an online meeting.

And this is someone that has the know-how.

Or just embracing interruptions and responding to them like an adult.

dnd signs read "passive aggressive"

And for the cost of zero you get something which is never used because forgot, did not have time, forgot to take off, lost the paper and the meeting started, missed the meeting running to the door to put the sign, and many others.

It depends on what you mean by convenient. A sign has low set up cost, so is convenient to implement. But it has an extremely high operating cost, that adds two extra steps to every meeting, which could add up to 40 or more per week. Small things you have to do often add up, and a quick task is still a task you have to remember every single time.

An automated solution has a high start up cost and is much less convenient to set up or to “fix” if it goes down. But it has an almost zero operating cost, in that you don’t have to remember or perform any additional tasks for a meeting.

For me, automating small tasks I have to remember to do over and over and over is very valuable to me, as those are the things that take up valuable space in my “stay on track” mind and distract from bigger more important tasks.

It's not about the price. It's because it's COOL - and because somebody did a fun thing with hardware and software, which is great!

>A “Do Not Disturb” door hanger costs $7 on Amazon.

"Please take a seat, I'll be with you in a few short hours."

Priceless.

Thanks, you inspired me to make something similar:

https://github.com/swills/onair

Simple way: don't use headphones and crank up the volume.

This is so awesome.

I thought about doing something similar during Covid, but mounted above the door frame.

Ended up getting a real office instead. WFH was great... until the toddler became tall enough to open doors :)

I use an Embrava Blynclight Mini, ~$60 on amazon, works fine.

Thanks for the shout out!

Well done! I've been thinking about something like this for a long time. I considered using the Google API to check for calendars but the camera is so much better an idea!!

as a generic aside, this seems like it's more of a "LAN of Things" project than an IoT device. It seems it would work fine if the upstream IP dialtone cut out for a while (though i'm guessing you wouldn't be doing too much video conferencing if that happened.)

but the core functionality doesn't require a server in the cloud, so by definition it's not IoT. just a nit though. it's still a cool little hack, no matter what you call it.

The definition of "IoT" requires neither Internet access nor cloud server functionality.

https://en.wikipedia.org/wiki/Internet_of_things

The core idea of IoT is that everything is capable of communicating on some network, whether that device is a fridge, a coffee maker, a dishwasher, a speck of dust, or a light bulb. The idea is that networks can connect more types of "things" than just general computing devices. The type of network and the reach of said network is sort of immaterial.

The author has created a specialized widget which communicates over a network. By definition, that is IoT.

To be fair, while the definition does not require internet connectivity, the name certainly does imply that it does.

Even the linked Wikipedia article points this out:

> "Internet of things" has been considered a misnomer because devices do not need to be connected to the public internet; they only need to be connected to a network and be individually addressable.

I suppose that's fair for someone who is not in-the-know.

But the definition of "internet" from an early point has been "a network of networks".

It is by historical accident that many people understand the proper name "Internet" to refer to a singular and monolithic thing. For many purposes, The Internet is monolithic, as it is a global interconnect and everything speaks IPv4 and is therefore globally addressable, if not routable or reachable.

But I would say that a "network of networks" is whatever you make of it. If it is a network of Bluetooth devices bridged by WiFi, that's an internet. If it's a dozen networks of washing machines in disparate rooms, bridged by a service provider, but not reachable by anyone without an app, that's an internet.

So in reality, it's perfectly logical to have multiple internets, interconnected internets, and isolated internets. The fact that China runs a "Great Firewall" means that their "Internet" experience is markedly different from an internet from a non-China perspective.

Last, but certainly not least: don't forget that the "S" in "IoT" stands for "security"!

I contemplated building this for myself back when I worked from home a lot. Great idea

Sonoff devices flashed with Tasmota firmware are fantastic for this.

In college, people would just put a sock on the door....

mDNS is really convenient. Unfortunately the only way to install it on Windows is through old iTunes installers.

I put a sign on my office door.

I have a similar system at home: there's a door on my office, and I close it.

i need this

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