Reverse engineering my Coway air purifier to ditch the cloud

I'm a simple man. I see people freeing their devices from proprietary clouds and reclaiming ownership, I upvote.

> The fan downloads its root CA cert over plain HTTP. It was always MitM-able.

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

Any number of people could have discovered and exploited this, but it’s tedious work. Most people who can do this are busy with their job and other things. Now LLMs enable people who understand these things to quickly get through the tedious parts, so they can do a lot more of this work in their free time than they could before.

This works better than all of the hepa purifiers on the market:

  1 20" box fan.
  4 20" mirv 13 filters (cheapest is likely costco or lowes or home depot - buy in a 4 pack to save money).

More info Search "Corsi-Rosenthal Box" or click https://filterbuy.com/resources/air-filter-basics/how-to-bui...

Don't go hepa because it slows down the filtering too much. I use this technique in my house and it cuts down on pollen, smoke and mold. You'll feel a lot better than a tiny expensive hepa that has proprietary filters.

Jeez. I've had a Coway for about eight years, such a good device that my whole perception was “good product == good company”. If I had known their IOT offering was such a POS I would think very differently.

That said, the non-wifi model works perfectly with a simple HomeKit compatible on/off plug, so all this work — despite being very, very cool — seems a little pointless?

I took a Vornado TRANSOM, a Broadlink RM4, and a Shelly Smart Plug, a Qingping Air Quality Monitor Gen 2 + claude and HASS, and now I have a fan that turns itself on when the CO2 level gets too high.

And I can override or change it from Apple Home.

The smart plug lets it verify that the fan is actually running, (because it measures usage) and we worked out that after a power cycle the Vornado goes back to a known state, and we can find the speed by forcing it all the way to 4 and then stepping back.

Has anyone managed to pull this off with the Levoit air purifiers. I've isolated mine on a seperate VLAN at home but it requires internet connection to control.

It is great to see another cloud mandatory device set free. I noticed lately several such entries in HN and personally it is a good trend.

I am wondering how the big corporate will respond sooner or later. Because it is clear and they know that as well with the every rising capability of LLM more people will find ways to liberate their hardware from such unnecessary dependency and accept less the money drain.

I wanted to do the same with Phillips air purifier that uses AWS IoT. Unfortunately, it seems the engineers did their job: an eMudhra-signed certificate was not accepted and the AWS endpoint also uses mTLS, so I wasn't able to MITM the connection.

Their ESP also uses Secure Boot... I don't know that there isn't a way to break in, but I wasn't able to find one short of hardware notification :/

I misread this headline and now I want a Cowsay air purifier.

I have 2 Coway air purifiers, they have no cloud stuff. They work really well.

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

I'm against a lot of smart home things because its actually more maintenance, not less, to have to think about an object connecting to wifi, to have to decide whether or not to control it (what are you even doing to it?) And I suppose to have to write your own drivers or app. Why allow it to occupy this much mental space for you?

I love how it has become a trend now to take some device that required a cloud subscription, reverse engineer it, then connect it to your own server you control.

Suddenly there are so many products to play with that would have previously been undesirable! This is one of the good things AI has enabled.

Will be interesting to see how things go in a few years when companies start rolling out devices where the software was built by LLMs

It will unfortunately be a lot harder to free those devices

All that to control one of 3 fan speeds. An extra slap in the face when it seems the motor used (at least in a similar model) appears to be continuously variable.

https://github.com/device-teardowns/coway-ap1512hh

This one yeets in a CA insecurely but eMudhra has been a gift for any that bake the CA--especially the abandonware unlikely to ever get patched.

If a company "banned" me from my ability to use the product I bought, that product would move swiftly to a skip-fire.

I can't express how happy stuff like this makes me.

Corsi-Rosenthal box is way cheaper and only connects to the 60hz.

I have a light with a controller on the cord: brightness up/down, power. I can't use a smart plug with it because it always defaults to off. Any ideas?

On topic, can you recommend a good air purifier to run in the office? 500 sq ft?

I am tired of having dust everywhere.

i truly wish these things were not smart in the first place

ChatGPT will allow you to do this interactively then ban you a few days later. Good luck OP.

We need a frontier to explore and exploit. Without it we turn inward, trying to chisel another 0.1% off each other.

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