[HN Gopher] Show HN: I've built an IoT device to let my family k...
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       Show HN: I've built an IoT device to let my family know when I'm in
       a meeting
        
       Author : delduca
       Score  : 84 points
       Date   : 2025-05-11 14:22 UTC (3 days ago)
        
 (HTM) web link (nullonerror.org)
 (TXT) w3m dump (nullonerror.org)
        
       | delduca wrote:
       | Source code https://github.com/skhaz/onair
        
         | gus_massa wrote:
         | 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_
        
       | sanex wrote:
       | 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.
        
         | delduca wrote:
         | That leak was intentional. ;-)
         | 
         | Come over to my place for some beers.
        
       | LurkandComment wrote:
       | I put a sign on my office door.
        
       | nine_k wrote:
       | 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.
        
         | OhMeadhbh wrote:
         | thx for the reference, though i think the bells and whistles
         | may have been the point.
        
           | nine_k wrote:
           | Indeed! Market segmentation ftw ;)
        
         | ctxc wrote:
         | It says $250 (but of course, pretty cool). Esp module is
         | probably <$10. What am I missing?
        
           | ctxc wrote:
           | Edit: misread parent, ignore.
        
       | neom wrote:
       | I use an Embrava Blynclight Mini, ~$60 on amazon, works fine.
       | 
       | See also: https://github.com/JnyJny/busylight
        
       | Liftyee wrote:
       | 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.
        
         | lurk2 wrote:
         | A "Do Not Disturb" door hanger costs $7 on Amazon.
        
           | function_seven wrote:
           | 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!
        
             | tekla wrote:
             | 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
        
               | varenc wrote:
               | sir, this is _hacker_ news
        
               | OhMeadhbh wrote:
               | 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.
        
               | lazyasciiart wrote:
               | 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.
        
               | rzzzt wrote:
               | An alternative would be to spin the sign constantly
               | around its center of mass while a meeting is in progress.
        
               | hackable_sand wrote:
               | The meeting state coheres when the sign is observed.
        
               | Dylan16807 wrote:
               | > 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_.
        
           | matsimitsu wrote:
           | Which is more expensive than an esp32 and a led panel, and
           | less convenient.
        
             | tekla wrote:
             | 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.
        
               | dathery wrote:
               | 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.
        
               | ctxc wrote:
               | Exactly! Do these things not bring people joy in the
               | drudgery of routine solutions?!
        
               | Dylan16807 wrote:
               | > 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?
        
               | lurk2 wrote:
               | > 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.
        
               | Dylan16807 wrote:
               | 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.
        
               | hackable_sand wrote:
               | Or just embracing interruptions and responding to them
               | like an adult.
               | 
               | dnd signs read "passive aggressive"
        
               | BrandoElFollito wrote:
               | 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.
        
           | sailfast wrote:
           | 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!
        
       | shadowgovt wrote:
       | I have a similar system at home: there's a door on my office, and
       | I close it.
        
       | Aziell wrote:
       | 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.
        
       | tonyarkles wrote:
       | 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.
        
       | franciscop wrote:
       | 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.
        
       | raggi wrote:
       | I've considered doing something like this a few times, this is
       | seriously ripe for an ON AIR sign :D
        
       | onair4you wrote:
       | 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.
        
         | ctxc wrote:
         | You should write about it and add pictures! :)
        
       | gia_ferrari wrote:
       | 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.
        
         | garyfirestorm wrote:
         | This sounds like a proper way to do it. Maybe I am biased for
         | MQTT but I like your approach.
        
           | BrandoElFollito wrote:
           | And HA which supports autodiscovery. Such a great piece of
           | software
        
         | pammf wrote:
         | 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 wrote:
           | 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 wrote:
             | 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
        
       | ThrowawayTestr wrote:
       | mDNS is really convenient. Unfortunately the only way to install
       | it on Windows is through old iTunes installers.
        
       | shermantanktop wrote:
       | 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.
        
       | OhMeadhbh wrote:
       | 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.
        
         | AStonesThrow wrote:
         | 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.
        
           | jader201 wrote:
           | 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._
        
             | AStonesThrow wrote:
             | 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"!
        
       | Aurornis wrote:
       | 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.
        
       | declan_roberts wrote:
       | 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!!
        
       | forgingahead wrote:
       | In college, people would just put a sock on the door....
        
       | jumploops wrote:
       | 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 :)
        
       | lemming wrote:
       | 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.
        
         | zimpenfish wrote:
         | 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.)
        
         | justinrubek wrote:
         | 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
        
       | turtlebits wrote:
       | What happens if you turn off your video? For large or long
       | meetings, I generally turn my camera off.
        
       | BrandoElFollito wrote:
       | 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.
        
       | deivid wrote:
       | 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
        
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