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Reverse engineering Xiaomi air purifier NFC stickers

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Re: Reverse engineering Xiaomi air purifier NFC stickers

#81

Post by criddell »

dxhdr wrote: post #26
iSloth wrote: post #11

I've never experienced an air purifier, what's the general consensus? Do they make a difference? Perhaps a placebo? A must have? Genuinely interested if I'm missing out - For what it's worth I do live right on a main road in the UK, so I expect there is some level of pollution in the air.

> Do they make a difference? Perhaps a placebo? A must have? Purchase an air quality monitor, something like the Dylos DC1100. Then run a HEPA filter in a closed room for 30 minutes. It will remove almost all particulates! They work extremely well. Whether it "makes a difference" for your health is less clear.

Are the lower priced options on Amazon junk compared to the DC1100? I’d like to get a monitor, but I know I’ll probably only use it 10 times. The Dylos would end up being about $25 / reading…

Re: Reverse engineering Xiaomi air purifier NFC stickers

#82

Post by ms4720 »

iSloth wrote: post #11

I've never experienced an air purifier, what's the general consensus? Do they make a difference? Perhaps a placebo? A must have? Genuinely interested if I'm missing out - For what it's worth I do live right on a main road in the UK, so I expect there is some level of pollution in the air.

Depends on a few things:

1. what that particular filter filters out: ppm, mold, chemicals 2. What is in the air being filtered 3. How sensitive you are to the things in your air 4. How often the rooms air gets filtered through the filter 5. How effective the filter is

I worked in Beijing for a while and going somewhere with filtered air literally felt like a weight was removed some days.

Re: Reverse engineering Xiaomi air purifier NFC stickers

#83

Post by joshvm »

BasilPH wrote: post #66

I've built dynomight's DIY filter[^1], and I love it. No DRM issues either. [^1]: https://dynomight.net/better-DIY-air-purifier.html

Perhaps a stupid question. Why go to the trouble of bolting together four filters, instead of attaching the duct fan to a cylindrical HEPA filter? Then you just need two plates: one to adapt the duct inlet and one to seal the base of the filter.

I think, as with many DIY projects, one must look to the pot growing community. They solved the problem of "how do I not stink out my apartment" a long time ago - duct fans and HEPA/carbon filters are the mainstay of grow rooms.

Re: Reverse engineering Xiaomi air purifier NFC stickers

#84

Post by bsder »

joshvm wrote: post #83
BasilPH wrote: post #66

I've built dynomight's DIY filter[^1], and I love it. No DRM issues either. [^1]: https://dynomight.net/better-DIY-air-purifier.html

Perhaps a stupid question. Why go to the trouble of bolting together four filters, instead of attaching the duct fan to a cylindrical HEPA filter? Then you just need two plates: one to adapt the duct inlet and one to seal the base of the filter. I think, as with many DIY projects, one must look to the pot growing community. They solved the problem of "how do I not stink out my apartment" a long time ago - duct fans a…

Link? I'm interested.

However, I suspect availability plays into it. Almost anyone can pick up a couple of rectangular HEPA filters and a box fan from the local hardware or big box store.

I've never seen a cylidrical HEPA filter. So, I probably need to order that from an industrial supplier.

And, aren't duct fans kind of noisy? Do they make quiet ones?

In addition, this fan/filter seems even easier: https://smartairfilters.com/en/blog/cannon/

Re: Reverse engineering Xiaomi air purifier NFC stickers

#85

Post by Someone1234 »

BasilPH wrote: post #66

I've built dynomight's DIY filter[^1], and I love it. No DRM issues either. [^1]: https://dynomight.net/better-DIY-air-purifier.html

Very cool. Anyone seen a mod that adds activated carbon? A lot of DIY filters are very cost-effective, but the lack of activated carbon is a big downside compared to commercial solutions.

There's really only two air cleaning technologies that are worthwhile right now:

- HEPA filters (remove PM 2.5 particulate and above).

- Activated carbon (neutralizes harmful gases).

The only other thing that may be worthwhile is a pre-filter, but that is mostly a cost saving measure rather than actually improving air filtration.

Unfortunately commercial filters are full of gimmicks that don't work or may even be harmful due to Ozone generation (e.g. Ionizers, UV lights, et al.).

Re: Reverse engineering Xiaomi air purifier NFC stickers

#86

Post by diziet »

SemAntics0 wrote: post #63
ehPReth wrote: post #52

Earlier quoted context omitted.

curious - why is Wirecutter trash? I’ve been sorta feeling iffy about them for no real reasons but they seem highly recommended

Years ago, they really drilled into the performance of the various products they compared and frequently the winner was a specialist product from a brand you had never heard of, but it really was the best on the market. Wirecutter articles did good testing with defined rationale that might not be up to laboratory standards, but it was enough to clearly identify which products were offering the best performance. When…

The Best Drill article doesn't even mention impact drivers, which are going to be tremendously easier on the wrist/hand for screwing in screws. An explanation for the lay audience would help. Nor are questions such as: "How much torque is there? What is the torque curve? How much torque do you need? Do you need a hammer drill? What is the noise like?" addressed.

I do think more specialty gear is hard to cover, as for example the the impact driver here: https://www.youtube.com/watch?v=l_pCeGmQU8w or AvE's youtube coverage of tools goes beyond that. Project Farm tends to have better coverage of general equipment with pretty good objective tests: https://www.youtube.com/channel/UC2rzsm1Qi6N1X-wuOg_p0Ng but even he can't cover all the brands/models: He covered Festool but not Hilti's SF 2H-A Hammer, for example.

Techgearlab has pretty unbiased coverage, and they also have an small incentive to cover products that have affiliate programs -- however, for example their parent rock climbing site Crash Pad Coverage: https://www.outdoorgearlab.com/topics/climbing/best-boulderi... includes Organic pads which have no affiliate program.

Re: Reverse engineering Xiaomi air purifier NFC stickers

#87

Post by joshvm »

bsder wrote: post #84
joshvm wrote: post #83

Earlier quoted context omitted.

Perhaps a stupid question. Why go to the trouble of bolting together four filters, instead of attaching the duct fan to a cylindrical HEPA filter? Then you just need two plates: one to adapt the duct inlet and one to seal the base of the filter. I think, as with many DIY projects, one must look to the pot growing community. They solved the problem of "how do I not stink out my apartment" a long time ago - duct fans a…

Link? I'm interested. However, I suspect availability plays into it. Almost anyone can pick up a couple of rectangular HEPA filters and a box fan from the local hardware or big box store. I've never seen a cylidrical HEPA filter. So, I probably need to order that from an industrial supplier. And, aren't duct fans kind of noisy? Do they make quiet ones? In addition, this fan/filter seems even easier: https://smartairf…

The duct fan + filter combo is how lots of cylindrical consumer units work (e.g. Levoit, Philips, etc). They just use crappy fans which don't really pull any air through, or they're very expensive for what they are. In terms of availability, I think the current popularity helped, otherwise you could also look at the auto market, lots of cylindrical filters there and they'd be fine for pulling out stuff like pollen, though you might want a carbon filter as well.

I have no idea what's required for HEPA certification, but lots claim to be:

https://www.amazon.com/LEVOIT-Core-Replacement-High-Efficien...

It has an outer dust mesh, the HEPA filter and a carbon insert. They're all the same though, I think you could use any manufacturer's filter. Longevity isn't really an issue if a supplier goes bust, just re-make the adapter ring. Pretty much all you need and you don't need to worry about sealing the corners.

According to OP's link, they use a duct fan booster which is a lot quieter than a box fan (at least the claim is it can go down to 16 dB).

Though a question is does a can-shape system work better? Or would you get the same effect if you used a single flat filter with the same "unrolled" area? I have no idea, and there's so much uncertainty involved with DIY testing.

Re: Reverse engineering Xiaomi air purifier NFC stickers

#88

Post by jrochkind1 »

bsder wrote: post #84
joshvm wrote: post #83

Earlier quoted context omitted.

Perhaps a stupid question. Why go to the trouble of bolting together four filters, instead of attaching the duct fan to a cylindrical HEPA filter? Then you just need two plates: one to adapt the duct inlet and one to seal the base of the filter. I think, as with many DIY projects, one must look to the pot growing community. They solved the problem of "how do I not stink out my apartment" a long time ago - duct fans a…

Link? I'm interested. However, I suspect availability plays into it. Almost anyone can pick up a couple of rectangular HEPA filters and a box fan from the local hardware or big box store. I've never seen a cylidrical HEPA filter. So, I probably need to order that from an industrial supplier. And, aren't duct fans kind of noisy? Do they make quiet ones? In addition, this fan/filter seems even easier: https://smartairf…

Hm, I feel like cylindrical HEPA filters are common for shop vacs and widely available? Searching "HEPA filter shop vac" on home depot gets what looks like plenty; or are these not what would work for that kind of design, maybe we're talking about different things? They are "cylindrical" by being pleated.

Re: Reverse engineering Xiaomi air purifier NFC stickers

#89

Post by dxhdr »

criddell wrote: post #81
dxhdr wrote: post #26

Earlier quoted context omitted.

> Do they make a difference? Perhaps a placebo? A must have? Purchase an air quality monitor, something like the Dylos DC1100. Then run a HEPA filter in a closed room for 30 minutes. It will remove almost all particulates! They work extremely well. Whether it "makes a difference" for your health is less clear.

Are the lower priced options on Amazon junk compared to the DC1100? I’d like to get a monitor, but I know I’ll probably only use it 10 times. The Dylos would end up being about $25 / reading…

Good question, I bought a Dylos back in 2015 and can't remember how the other options stacked up when I researched it. I've been happy with the purchase and would recommend it if you're interested in watching air quality. It has a convenient "monitor mode" where it will re-sample the air every hour so it's not constantly running. It's neat to see how the air quality in a room changes based on having the windows open or shut, after cooking, just being in the room, etc.

I'd expect there are smaller / sleeker / more advanced monitors out now though. Generally speaking I think you want a laser detector instead of the cheaper infrared detectors.

Re: Reverse engineering Xiaomi air purifier NFC stickers

#90

Post by papercrane »

Someone1234 wrote: post #85
BasilPH wrote: post #66

I've built dynomight's DIY filter[^1], and I love it. No DRM issues either. [^1]: https://dynomight.net/better-DIY-air-purifier.html

Very cool. Anyone seen a mod that adds activated carbon? A lot of DIY filters are very cost-effective, but the lack of activated carbon is a big downside compared to commercial solutions. There's really only two air cleaning technologies that are worthwhile right now: - HEPA filters (remove PM 2.5 particulate and above). - Activated carbon (neutralizes harmful gases). The only other thing that may be worthwhile is a…

You could buy an activated charcoal filter built to attach to the same inline fan booster from most garden stores that carry indoor growing equipment. They're popular with people growing cannabis indoors to remove the smell from their grow area.

Something like this:

https://www.amazon.com/dp/B07GSKFBL8/

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