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Experiments on a $50 DIY air purifier that takes 30s to assemble

dyno-might.github.io

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Re: Experiments on a $50 DIY air purifier that takes 30s to assemble

#141

Post by WalterBright »

fencepost wrote: post #83
WalterBright wrote: post #16

Another way to do it is to bubble the air through water. As a kid, we did an experiment where a cigarette was "smoked" by attaching a tube to the cigarette filter, the tube exited at the bottom of a flask filled with water, and a pump would suck the air from the top of the flask. It didn't take long before the water would turn black. Quite a turnoff for wannabee smokers, which was the obvious point of the experiment.…

Another way to do it is to bubble the air through water. As a kid, we did an experiment where a cigarette was "smoked" by attaching a tube to the cigarette filter, the tube exited at the bottom of a flask filled with water, and a pump would suck the air from the top of the flask. "We built a bong and discovered that bong water is really nasty."

Thanks for the great laugh. I never thought of that!

Just think of that nasty bong water being what the smoke does to the fluids in your lungs.

Re: Experiments on a $50 DIY air purifier that takes 30s to assemble

#142

Post by cleorama »

throwaway9d0291 wrote: post #44
ahaucnx wrote: post #21

We have open source, open hardware build instructions for a very reliable Air quality sensor that can be used to measure PM2.5 and also CO2. https://www.airgradient.com/diy/ We have tested it extensively and it is very accurate for the fraction of the costs of commercial sensors. You can build it for less than USD 20 and send the data to our cloud server or any other backend. We also measure CO2 because if you have p…

I've seen references to this sensor before and find it a bit concerning that there's no information about how to properly use the CO2 sensor. This sensor uses a SenseAir S8, which like most CO2 sensors, has an automatic baseline calibration algorithm enabled [0], which expects to see pure, undiluted fresh air at least once every 8 days. The only way to disable it is explicitly, through the MODBUS interface [1]. Leavi…

Is there a CO2 sensor (part) and/or a CO2 monitor (device) one can buy that is well-suited for residential spaces?

Re: Experiments on a $50 DIY air purifier that takes 30s to assemble

#143

Post by rootusrootus »

post_break wrote: post #91
rootusrootus wrote: post #89

Earlier quoted context omitted.

> we'll use two 20x25x1 filters which increases the filter surface area over 250%. That seems like an overly complicated first attempt, why not just switch to a 20x20x4?

Those can be harder to source I've found. Cheaper to use two filters than one as well since you can replaced the prefilter more often.

But more difficult, yes? Stacking filters is very different from getting a thicker filter. The former increases air resistance, the latter decreases it. So to get the equivalent behavior from two 20x20 filters, you'd have to device some way of routing air through both of them in parallel.

Re: Experiments on a $50 DIY air purifier that takes 30s to assemble

#144

Post by peteretep »

ionwake wrote: post #108
peteretep wrote: post #75

Earlier quoted context omitted.

https://smartairfilters.com/en/sqair/ It’s a fan + a HEPA filter and it’s kinda pretty

Do you know how long the filters last?

Depends how long you run it and on what speed. I seem to remember we were working on the basis of changing it every three months if we ran it continuously during that time

Re: Experiments on a $50 DIY air purifier that takes 30s to assemble

#145

Post by denimnerd42 »

jeremywho wrote: post #121
JJMalina wrote: post #111

Earlier quoted context omitted.

The Plantower PMS5003 PM Sensor is unavailable to ship to the US on aliexpress https://www.aliexpress.com/item/32944660534.html Do you know of another supplier that ships to/within the US?

I'm looking for this as well. The only think I found was https://www.adafruit.com/product/3686 , but thats 4x the price of aliexpress.

https://www.aliexpress.com/item/4001039451614.html

Re: Experiments on a $50 DIY air purifier that takes 30s to assemble

#146

Post by [deleted] »

Mister_Snuggles wrote: post #63

The only downside of the DIY route is the noise. Most box fans that I've seen are very noisy relative to "real" air cleaners/purifiers. I've used a box fan plus furnace filter for years to deal with cat litter dust. Since the particles I want to filter are quite large, I can get away with using a fairly cheap furnace filter. The nice thing about this is that it's really easy to scale it to your requirements. To deal…

[deleted]

Re: Experiments on a $50 DIY air purifier that takes 30s to assemble

#147

Post by xwdv »

quercusa wrote: post #137
xwdv wrote: post #38

Earlier quoted context omitted.

They want to change what they charge from time to time so putting a price up front will force them to leave money on the table. Not gonna happen. Contact them instead.

When you can get quotes for satellite launches[0] without calling anybody, it feels like unnecessary friction at best. [0] https://www.spacex.com/rideshare/

That’s mostly for PR.

Re: Experiments on a $50 DIY air purifier that takes 30s to assemble

#148

Post by Havoc »

xnyan wrote: post #12
Havoc wrote: post #10

Earlier quoted context omitted.

Not really. To remove smells ozone generators are used. That stuff is really dangerous though

This is not correct. Activated carbon is very effective and in wide use for odor removal.

>This is not correct.

No it's not.

That 200 USD fine for smoking in hotel rooms? What do you think happens afterwards? Buy a bunch of activated carbon filters? Or get a professional ozone odor removal provider to roll in their with their gear?

Re: Experiments on a $50 DIY air purifier that takes 30s to assemble

#149

Post by throwaway9d0291 »

cleorama wrote: post #142
throwaway9d0291 wrote: post #44

Earlier quoted context omitted.

I've seen references to this sensor before and find it a bit concerning that there's no information about how to properly use the CO2 sensor. This sensor uses a SenseAir S8, which like most CO2 sensors, has an automatic baseline calibration algorithm enabled [0], which expects to see pure, undiluted fresh air at least once every 8 days. The only way to disable it is explicitly, through the MODBUS interface [1]. Leavi…

Is there a CO2 sensor (part) and/or a CO2 monitor (device) one can buy that is well-suited for residential spaces?

Any CO2 sensor (part) that gives you the ability to turn off ASC should work just fine and most of them do, you just need to trigger it.

Personally, after trying out a bunch of sensors, I use the Sensirion SCD30.

As for devices, I'm not aware of a consumer device that I'd recommend. If you're willing to do at least a little bit of DIY, Watterott [0] sells an SCD30 hooked up to an Arduino-compatible MCU with WiFi, a red/green/blue indication of CO2 levels and ASC disabled by default [1].

It's an open-source hardware design and software [2] and has a few reference firmwares [3], including one [4] for MQTT.

If you want to go a little bit further, I'd recommend an ESP32 with an SCD30 and ESPHome [5]. That's what I use myself, mostly because I already had the sensors prior to Watterott's product existing.

[0]: https://shop.watterott.com/

[1]: https://shop.watterott.com/CO2-traffic-light-Plus-version-Wi...

[2]: https://github.com/watterott/CO2-Ampel

[3]: https://learn.watterott.com/breakouts/co2-ampel/

[4]: https://github.com/mariolukas/Watterott-CO2-Ampel-Plus-Firmw...

[5]: https://esphome.io/

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