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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

#61

Post by spthorn60 »

StavrosK wrote: post #58
spthorn60 wrote: post #5

As most home woodworkers could confirm, a filter-on-a-box-fan works wonders in a (saw)dusty garage. Even after sanding or sawing MDF, the air is clean after about 10-15 minutes. From personal observation, I'd suggest that non-taped is a good idea, as any non-filtered air is routed through the fan to help overall circulation; ideally you want to displace all the air in the room quickly.

How long does it take to clear the air without the filter? I'd imagine sawdust is heavy enough to fall down on its own after a while.

Right the heavy stuff falls pretty quickly. The light particles will take quite a long time, and in the meantime, you're potentially breathing all that. I use a large cyclone for the machinery, a filter-on-a-fan, and a mask. My shop is a lot cleaner than it used to be, and I'm sure my lungs are too.

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

#62

Post by Ottolay »

shared_frog wrote: post #33
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 appreciate your DIY instructions, but I really dislike how your website goes through the effort of hiding what you actually sell and also how much it costs. I don't want to "contact you" to get that information. We've been long enough in the 21st century that it has become an adult, and still I keep running into this archaic nonsense. For example, you mention your "sensor package" in the FAQ and that's it. Your DIY…

I would be willing to go together to have a set of PCBs if you are interested. Usually there is volume pricing.

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

#63

Post by Mister_Snuggles »

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 with the noise, I used a motion sensor and switched outlet to only run it for 10 minutes after the litter has been used. This runs through my existing home automation stuff (Home Assistant+Node-RED), but it could also be done with an Arduino (you don't even something that powerful - two I/O lines is enough), a PIR sensor, and a solid state relay for the fan control.

I've tried a number of low-dust/no-dust litters, but most of have lead to the cats finding other places to do their business or have disappeared from store shelves when I've needed to replenish it. Everything about this is a compromise between litter acceptance, litter availability, litter cost, filter cost, filter life, noise, and dust production.

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

#65

Post by platz »

shared_frog wrote: post #33
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 appreciate your DIY instructions, but I really dislike how your website goes through the effort of hiding what you actually sell and also how much it costs. I don't want to "contact you" to get that information. We've been long enough in the 21st century that it has become an adult, and still I keep running into this archaic nonsense. For example, you mention your "sensor package" in the FAQ and that's it. Your DIY…

Usually this means the company does not sell to consumers and is b2b only, similar to how you just can't buy something anonymously online from a wholesale distributor.

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

#67

Post by gh02t »

Ottolay wrote: post #62
shared_frog wrote: post #33

Earlier quoted context omitted.

I appreciate your DIY instructions, but I really dislike how your website goes through the effort of hiding what you actually sell and also how much it costs. I don't want to "contact you" to get that information. We've been long enough in the 21st century that it has become an adult, and still I keep running into this archaic nonsense. For example, you mention your "sensor package" in the FAQ and that's it. Your DIY…

I would be willing to go together to have a set of PCBs if you are interested. Usually there is volume pricing.

It might not be worth it to organize a big order nowadays, PCB fabrication is already super cheap. JLCPCB (and others, but I have the most experience with them) will do 5 boards for $2 + shipping and the first order gets free shipping. I've used this service for prototyping many times and had great experiences.

I had been planning to build almost the exact same thing as what the parent posted but had been putting it off because I didn't want to draw up a PCB, so this is perfect.

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

#68

Post by metiscus »

joncrane wrote: post #56
Traubenfuchs wrote: post #41

Earlier quoted context omitted.

> In a normal room you can see the laser beam in dark. Dear god, do you live next to a coal plant? I would argue that in a normal room one should NOT be able to see the laser beam!

You'd be surprised how "dirty" (dusty) the air inside houses is.

Especially given the relatively wide range for age and consequently construction type. I've found that newer drywall construction tends to be more dusty in my limited experience than well maintained plaster and lath.

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

#69

Post by tk75x »

dole wrote: post #60
totetsu wrote: post #52

water filters also have the incompatible proprietary filters problem. I wanted to try filtering some water so I could make coffee that wasn't bitter but every water filter seemed to want me to buy a bunch of plastic to go around a replaceable filter. In the end I settled on pyrolysized cherry wood branches, (activated carbon, or biochar). It seems them carbonated bamboo is also used in tea making. It worked but it ce…

In the spirit of DIY/OSS here, I think ideally you’d want to emulate something like a Berkey water filter, these are basically just steel tanks with large threaded cylindrical charcoal filters (2” diameter, ~10” long) that use gravity to pull the water from the top to the bottom. A simple 3D printed housing filled with some charcoal/carbon media to trickle filter like a Brita would be interesting to see its effective…

At my parents house, we set up a whole-house water filtration system by repurposing water softeners. empty the guts of one, refill with aquarium supply activated carbon, then adjust the electronics to your liking and you're good to go. Those systems are designed to run 24/7 and soften/filter all the water going into your house.

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

#70

Post by exhilaration »

nkurz wrote: post #53
NietTim wrote: post #29

Interesting. I only have central ventilation but my mom has central heated air in her house, in theory she could chuck a HEPA filter in front of it to get cleaner air in all of her house.

Note that this can be a really bad idea. While it might temporarily improve the air quality, extreme filtration will reduce the air flow through the system. This will in turn reduce the efficiency of the heater, possibly in a way that causes its internals to overheat and destroy themselves. Rather than "upgrading" to higher filtration, you are safer replacing whatever filter is there with a new clean one that matches…

I've read the same thing, that if you put a heavy duty filter on your furnace you put a heavier strain on the motor and risk burning it out. I'm not an HVAC professional so research this yourself.
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