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  > The most fascinating part of this wave of LLM reverse engineering is seeing how many weird and poor choices were lying in plain sight.

But in some weird way we're coming to the day of reckoning. I'm sure we'll always have missed bugs but with a lot of what we're seeing it more seems like these were avoidable problems. Code issues I can easily imagine at least one person on the team said "this isn't acceptable, we need to correct it" and them getting overruled. I'm sure each and every one of you has seen, if not experienced, this.

It'll be interesting to see if that continues. I suspect companies will still rush but from my experience even the best models happily produce shoddy code. And there's a feedback loop, the model's performance is influenced by the code's quality. So it's easy to degrade and get into a bad feedback loop. But I think people still value speed over quality, even in this world where Microsoft shit the bed

[0] in quotes because the entire conversation is essentially about what is actually good enough and what actually is the minimum viable product.

"The fan downloads its root CA cert over plain HTTP"

Would love to understand the decision-making behind this at Coway (or their firmware contractor). Anyone care to guess why someone would make this choice?

Similarly, how easy things are for more people to do. I'm certainly not advocating for pulling in a root CA over HTTP, but before LLMs could make this knowledge trivial, how many people would even think to look at that angle. It's democratizing in an interesting way.

It is an interesting thought experiment: what things happen once the inertia cost to seeing how something works collapses to 0 for even a small number of your user base. Smart companies might give in now and open up their app even if only as a read-only repo. Dumb ones won’t even know to consider it. And the huge middle will wind up getting new UX ideas for free.

I remember when people were like LLMs write insecure code. Well, so does literally everyone apparently, Maybe that's where it learned it. I feel like that group has gotten a lot quieter lately.

True, but the MacGyver looking thing in the middle (or side,whatever) of your living room doesn't sit right with everyone. People pay money for aesthetics and take the hit on efficiency.

I'm seeing some 3d printed projects popping up that look to be filling this gap though.

Filtering out the fines and ultrafines – the stuff that HEPA filters capture – makes a biiiiiiig difference in air quality.

A smaller supplementary unit made out of PC fans and N95s can do that. A 120mm Noctua fan's flow and pressure fits well for about three 3M Aura masks in parallel.

It's unhinged how good the air quality is in a room with a device like this.

We've been doing the $9 Amazon Basics fan with a good filter since wildfire smoke started really getting bad in the bay area, quite a few years ago now. We had a couple of big, expensive filter tower things, and they helped, but just a couple of the boxfans with filters duct taped on quickly and consistently annihilated PM2.5 and PM10 in our apartments.

Most surprising thing: all but one of those original Amazon fans is still running. They've had years of run time, at quite a bit higher stress than normal.

I agree on principle. There are iterations on this concept that are much quieter, are visually more palatable, and still have high airflow.

Example: https://www.cleanairkits.com/products/luggable-ultra-air-pur...

That rules! Looks like you can do it with like 3 filters so it's more triangle shaped which makes sense. That's so stupidly simple too. Also aesthetically pretty cool - would look great in a workshop where it's like function first/don't hide the mechanism. And I feel like there's gotta be clever ways to incorporate something as simple as "box fan but the box is made of air filter" into like a coffee table or stand or something else clever? Probably you'd want to hide the filters inside if they look grimy before you actually need to replace them so you don't feel obligated to waste money by replacing too soon but sounds like a fun time to figure out how to integrate that in a hidden way into whatever's your vibe without looking jank

What is the advantage of this over just sticking a merv13 in your HVAC and running the fan for 15minutes every hour? (assuming it's rated for merv13)

In my bachelor days I put an air filter behind a box fan; women have higher aesthetic standards. mirv 8 works fine for me and I can pick them up grocery shopping, but my primary contaminant is a sheprador.

I’m not dedicating 1600 cubic inches of my living space to an ugly homemade piece of furniture that I have to rebuild whenever I change a HEPA filter. I suspect I am not alone in this.

I was wondering when one of the low-end 20" box fan vendors would add a slot for a 20"x20" filter... and it turns out Lasko finally did, creating an "AirFlex 2-in-1" product that's often knocked for price/noise but resolves the homemade look, for those that care.

I never get this take. Yes, you'd make this in a pinch but that thing is hideous to have around the house.

It's like telling someone they bought a car and pointing out that golf dimples with increase your mileage. No reasonable adult would have that thing in the middle of their living room!

My brother in law did this. It is boxy and ugly, but damn does it work.

I would build one but I live in Argentina and I have no idea where to get any of the components.

Everyone wants the sound of a box fan and the looks of duct taped cardboard sitting in their living room...

You can take it with you when your wife kicks you out of the house for making something so stupidly ugly even if its functional.

Related, don't know if it would have worked with your system https://cloudfree.shop/products/ductless-hvac-wi-fi-module

Small world, just submitted PRs to add Vornado Strata 433mhz decoder to rtl_sdr :)

Need to try to get Sonoff bridge rigged up next but have been busy messing with Hatch alarm

Nice! I have a similar setup. You might like the custom visualization or temperature and humidity offsets I’ve made for that air monitor. Its screen and battery cause excess heat to throw off readings and the calibration is rough from the factory, I used a cheap bluetooth govee thermo-hygrometer as reference to build a better cal curve.

It's so few hobbyists doing this that I doubt they care. Awesome for us though!

Can't crank up the fan with an on/off plug.

Based on personal experience, HEPA isn't even necessary when you're filtering that much air.

My house downwind of a freeway and a wilderness area, lots of nasty black tire dust mixed with allergens. It did not come with A/C. I had HEPA air purifiers around the house that I would leave in auto mode and they would run for a few hours a day based on the air quality.

Then I got central A/C installed with a standard 1" MERV 10 rated filter on the intake. Just running the blower for 10 minutes every hour is enough to keep the air quality in every room below the level where the air purifiers would kick on. I've given most of them away.

HEPA is less important in most scenarios than "something that on a few passes will catch everything", which MERV-13 will do. Not all systems can handle the pressure drop of a MERV-13 but many can, and there are some pretty low-drop options out there if you search for them.

Had Claude build a Home Assistant integration for my Rheem furnace which exposes commanded ECM CFM, actual CFM, fan RPM, static pressure (among other things) via Bluetooth Low Energy.

We don't have central air in our new home and man oh man does it get dustier. I did not appreciate the power of those cardboard filters.

This is not a good choice for everyone. Before greatly increasing the load on you HVAC blower motor, make sure you first understand where it is, how old it is, and how inconvenienced you would be if it burned out.

There is at least one big downside to running the fan 24/7: you lose out on humidity control.

Annoyingly, both Ecobee and (at least historically) Nest make controlling the fan independent of the heating and cooling hard. You have to enable either heating or cooling before being allowed to enable the fan. And you can't specify how long you want to run it for, but have to select one of a few options.

/ Your reasoning is excellent -- it's \

| only your basic assumptions that are |

\ wrong. /

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        \   ^__^

         \  (oo)\_______

            (__)\       )\/\

                ||----w |

                ||     ||

Not sure about air purifier, but I have a Midea dehumidifier and it publishes runtime and setpoint info I pull into Home Assistant along with power draw from a smart plug. I can see how often it's running at different times of the year and how much it costs. Ended up saving some money tweaking it from 50 to 55 after seeing runtime and A/B testing both.

Also auto on/off. If you put Home Assistant app on your phone, you can wire up automations that turn things on and off depending on whether or not you're home. Could also have Home Assistant pull in air quality/pollution info for auto on/off. High pollen count today? Keep it running so I sleep well. Low pollen count? Turn it off.

Maintenance is minimal. I set the dehumidifer up 2 years ago and haven't touched it since or had a single issue. Main thing is a) get it working, b) get it isolated from internet, c) never touch or patch it.

Once the data is in Home Assistant, I can also look for correlation with wearable health info. Does purifier running improve sleep? Does changing thermostat set point improve sleep?

It’s just a remote control. Why did the tv started coming with a remote control. It’s convenient.

Setting up almost never takes more than a few seconds for me. I have Apple home, it’s almost always scan a QR code, wait a few seconds for wifi and done.

Also it’s fun to mess with.

> I'm against a lot of smart home things

What I like about IoT is the idea of hacking them :-). Of course I don't want connected devices running proprietary firmwares anywhere near my LAN.

Also one thing is that when a company sells an IoT device, maybe they mass produce it and it's cheap. Whereas if you wanted to build it yourself, it would be harder. Getting relatively good and cheap hardware and putting your own software on it is nice!

The article explains why: the author’s wife cranks it up for white noise while they sleep, and the author wanted to tie that into their existing “go to sleep” home automation.

>> Why not just get a not-cloud one in the first place? Why does an air purifier need to be controlled via wi-fi?

It is convenient to be able to monitor air quality from your phone, sourced from a device that is designed to improve it. Because then you can see how much of an impact it is actually making, move it to a different location with better airflow, etc.

I have the non-wifi version, and have to use a separate device for it.

Enjoy it while you can. You can see the AI companies have already started the process of locking us out of this, with Opus 5.5.

God forbid our fans, our fans of all things, might be broken of their dependencies on the internet. The plebians can't be allowed to do that. Every relay must be cloud-connected so it can be monetized and disabled for whatever dumb ass reasons someone might want to disable it.

A CR box certainly has its place, but for many people that place just isn't in their nicely decorated home.

Any resources you could share here? I bought a Rabbit air filter years ago and it seems like it does fine. But since I did something similar to the OP here and started tracking my Awair air quality monitor in real time, I’ve noticed we have wild VOC levels in our roomy house and I can’t sort out what causes spikes, especially overnight. Some of it is probably due to the insulating and weather stripping mania I went through a while back and I’ve looked into getting an exhaust fan (whatever those things are called) to alleviate it but would like to know the source(s).

Thank you for this. I've been looking into buying air filters and would have made this mistake. (HEPA sounds good!)

I'm confused by your dust and pollen comment. What about PM2.5, is this mostly dust or are you not that concerned about this vs dust?

This is very helpful. Thank you.

Are there any example builds you could point me towards?

I don't think I've ever said this on HN, but: delete your post. It's nonsense.

    Because it's so fine, you need a VERY powerful 
    fan to move any air through it, which means the 
    purifier will be very loud.

"For a purifier of its capabilities, the Mighty is notably quiet" - https://www.nytimes.com/wirecutter/reviews/best-air-purifier...

Alternatively, just take a glance at the ~30K reviews on Amazon. - https://www.amazon.com/dp/B01728NLRG

    It doesn't matter how amazing your air purifier is if it 
    sounds like a tornado. If you only run it for a few minutes 
    before getting annoyed, the purifier is not doing its job. 

    Combine MERV13/14 with off-the-shelf PC case fans (which 
    have been optimized for decades to be as quiet and long-lasting 
    as possible) and the result is an easily-maintainable, quiet, 
    highly-effective purifier.

For a given CFM, with all other things being equal, larger fans (like the ones in Coways) are going to be easier than a bunch of smaller fans. Though, if using an array of Noctuas or similar, I'm sure it could be done.

    Many purifiers try to use sensors to determine when to 
    run the filter, but this fundamentally a flawed approach 
    and just means you have low quality air 99% of the time.

    The solution to these problem is a less-fine filter. For dust and 
    pollen, something like MERV13/14 is absolutely fine.

    off-the-shelf furnace air filters that are VERY cheap compared to 
    custom-fit HEPAs which may stop being made the moment that purifier 
    product line inevitably ceases to exist.

But have you actually taken 30 seconds to look on Amazon and noticed the dozens of third-party filters made to fit the Coways? It's like buying Bose headphones. Yeah, you'll need to replace the earpads eventually, but they've been using the same earpads for like 15 years and there's an ecosystem of cheap 3rd-party versions... not 100% ideal, but also not a problem. As you note, maybe the situation's different outside of the US.

Cut the controller off and use the smart plug to control brightness. You might need to open it up and replace the power supply.

I'm going to guess that you will spend more money on this than just buying a light that has smart features compatible with your smart home ecosystem. You can't mix two smart systems on one cord - this has never worked. Where to put the smart is a tricky question as there are pros and cons to every answer, but in general the smarts need to be in exactly one place or things won't work.

Unironically a gift. On your own home network, the one most likely to MITM you is yourself. And eMudhra's fuckup allows for a nice attack on a few devices you'd otherwise have to disassemble to pwn.

Coway are some of the best, and there are many dumb models without internet access at all

If you don't mind the hum of fans, it's hard to beat a Corsi-Rosenthal box... there are kits from cleanairkits.com or cybernightmarket.com to build quiet PC fan based boxes that in my experience work excellent and can use off-the shelf filters and parts

a box fan and a furnace filter.

I've reverse engineered and jailbroken a few devices I own using OpenCode & an OpenAI subscription. No bans yet.

Some kind of final frontier, perhaps?

I am a simple man. When I see people buy devices with Zigbee, Z-Wave, or other fully local protocols, I nod. When I see people reward vendors that lock in with their money, I shake.

You love to see it!

I (with heavy LLM help) recently R.E. a golf cart motor controller which had a USB interface for programming, but only a crappy proprietary windows application, and it was super satisfying to see it hum attached to Linux.

What would be even more satisfying to see would be companies that were chill about this kind of work, instead of sending[1] legal threats[2] to people doing the work that they should be doing in the first place.

1: https://news.ycombinator.com/item?id=50443824

2: https://news.ycombinator.com/item?id=50363968

I'm with you in theory but why on earth is anyone buying an air purifier that requires cloud connectivity at all?

Anyone want to help create a generic service to do this for any IOT device?

Basically a git repo with instructions that would maybe pull in rea and set all this up.

How realistic is this with the emuhdra and other certain vulnerabilities now exposed and will be locked down?

I really can't understand why the hell these manufacturers don't just provide open source firmware. Nobody is buying a Conway purifier for the software and there are no trade secrets there.