Final air purifier? With 3D scripts

Interesting to see IKEA has started selling air filters. Must have seen your videos. https://www.ikea.com/gb/en/p/foernuftig-air-purifier-black-40488065/ They also have a £10 "Air quality sensor" which just seems to be a dust sensor. https://www.ikea.com/gb/en/p/vindriktning-air-quality-sensor-80515910/ Thinking about buying the air sensor just to take apart amd see if it's hackable.

SmithyScotland

Sounds like the voice of experience, it's off and thanks Clive

I'd recommend against that. There's a risk it may trip a thermal cutout with the reduced air flow.

Big Clive

Just put a kitchen towel sheet over the back of one of my Ecoair Simple, fits a treat, 20mm 3M top and bottom, sides perfect - I reckon the tape is the most expensive part!

It's on a much larger scale than yours, but I made a DIY air filter using two furnace filters (commonly available everywhere in the USA, not sure about the UK), a box fan, and duct tape. It's a lot less professional than 3D printing a frame but it works very well. Originally I had just one filter taped directly to the fan but I discovered that using two in a triangle shape with a void in the middle worked a lot better. Photo: https://david.gloveraoki.net/f/fanfilter.jpeg

David Glover-Aoki

Nice one Clive. Printed one of these today. Working great. I will install it in my very dusty bedroom and see if it can capture some of that dust. More projects like this!

This is awesome! Thanks for providing the scripts! Don't have a 3D printer yet but projects like these get me closer and closer to getting one! And I do vote for small recesses for magnets to hold the top plate in place.

Jon

Magnets are still a good idea. With small magnets and built-in recesses for aligning them.

Big Clive

I've added some to my CPC shopping basket for the next order.

Big Clive

CPC have carbon filters (SD01240) designed for soldering fume absorbers. Might be good to catch the big particles before they reach to toilet paper. 130mm x 130mm. 5 for £5.

SmithyScotland

I agree, add an ioniser, but have the negative electrodes in the open and a positive plate between the paper and top screen. Just some wire or foil to attract the negatively charged dust onto the filter.

A calibration sheet and filter sheet might work.

Big Clive

If you are going to have a top plate, having it click in place with some neodymium magnets would make changing the filter oh so satisfying.. [edit] I just reached the part of the video with holes and pins... nah.. If Apple have taught us anything...

Gordo

The advantage of 3 feet becomes evident when your surfaces aren't quite flat

Gordo

How much do the particulates we're talking about weigh? Could you get some precision scales and weigh the filter before and after, and show that you've filtered 0.05g of stuff or whatever? Or are they too light for that?

The zig zagging is easy, but sealing the edges to make the air go through the paper isn't. Even a shaped frame that folds the paper as a series of ridges when closed would probably rip it in doing so.

Big Clive

Astronaut's Lovell, Haise and Swigert would applaud the simplicity. Add a little duct tape, carbon and Clive could save a capsule. FYI, I doubt Clive will hurt Honeywell's bottom line but then again ( proof of concept) is the goal right? I'm pretty sure it wouldn't take long to ziggy zag your filter tissue to increase through put.

Jim

I'm not aiming at a full sized filter performance. It's a low airflow through a regularly changed filter that can happen nearly silently 24/7. Over that time a decent amount of air passes through the filter.

Big Clive

Not sure. It's a very low airflow.

Big Clive

I did have my doubts if this would work, so I build a "Show-box" version of the filter (with a little too noisy fan) The filter (kitchen paper) have turned quite brown in a couple of days. So the principe in BG's filter is sound in my opinion. I'm going to source a better (more quiet) fan - but will probably stay with the "Show-box" design as I am having some issues with my 3D printer when printing large objects.

Zeedijk Mike

What you should be using is PC fan screws - self tappers made specifically for fans that screw directly into the plastic - no nut needed.

Gadgetman

Add an ionizer. I like this project so far. Will probably do one in wood. I don't have a 3D printer. Please discuss your thoughts about ionizers in this application, either full-time running or partial. Cheers, mate

Chuck Kirchner

I don't think the idea is to compete with a commercially designed, dedicated air filtration system; at the volume of air the fan will draw through the tissue membrane vs the volume of air even within a smallish room - you're probably right however, the air that is drawn through the tissue, will be filtered and I think the filter tissue, over time, will show quite noticeable signs of dust being trapped, probably more obviously, where the openings are in the filter housing (leaving lighter patches where the frame / lattice would be beneath / where air cannot pass) . Will that room become noticeably less dusty? I wouldn't think so but that would filter and the filtrate in this context has a small enough weave to capture the density of particles Clive described. We've all seen the amount of dust that builds up around those small fan-cooled electronic items such as PC's, PSU's, CCTV systems etc. They don't have filters and that visible dust is just deposited - most of the dust that passes through those fans is just fed back into the room. This idea will trap that in the filtrate. It's just a bit of fun don't forget but I expect it to work just fine. I'll try it, my 3d Printer arrived though its being replaced hopefully by Saturday.

The pattern does not really matter visually since it is covered with paper. The square pattern is better since the filter area is larger.

As I said before, this won't work. The filter doesn't have enough surface. Any real air filter you see has folds upon folds upon folds of filter material. Plus, which is not immediately obvious, the folds themselves have a wavy pattern, increasing the surface even more. I don't really understand how you think you can build something very simple, that uses something very cheap as a filter, consumes very little power and is tiny, but still works anything approaching as well as a proper, big, powerful specialised device. Ain't happening. The devices you can buy are indeed essentially a fan to draw air through a filter, but the filter itself (and the coarse filters before) is where the smarts is. Ask your HVAC buddies about this, they should know a thing or two about filters (and how much air a filter must move to be effective). I'm afraid the premise - using tissue paper as filter - is simply flawed.

horrovac

this is interesting... I can do this for the area near my cat boxes so I an limit the amount of litter dust in the air... Nice. :)

Ryan Coleman

Any idea of what CFM this model is being run at?

Full Name

or 3 magnets and three bolts resessed into the lid

Full Name

Nice. I'm going to try to modify this for a 80mm fan (all I have to hand).

Paul Hill

dad leaves his full hull houseboat at the marina for the winter (.us), you need to cover it to make sure snow/etc doesnt get in, but also there is a main trainline next to the marina, if you dont cover, the boat looks like its got smallpox/etc as the deisel from the train engines really does a job on fiberglass, esp older fiber.. ick

Scott Traynor

Nice one!, Living next to a motorway, the shite that comes through the windows is unbelievable. A simple, yet elegant idea, Ile definitely be building a couple of these to test, thank you.

With the filter retainer ring one idea could be to use 6 very thin Neodymium disk magnets, 3 with in notches on the ring and 3 on the grid. As for the grid pattern, the most efficient for strength/material use/area are hexagons in a honeycomb layout. Another option if looks are not a problem is to leave the hole open without a mesh and add a support like fly wire or a metal mesh later. In regards to turbulence the rate/volume is so low that the percentage difference between an optimised and un-optimised design performance is going to be very low, not really worth the worry. But if it is the principal of the thing then holes with a depth greater than 2x the width are a good start in designing a grid for a reduced turbulence.

I like that! I've been using carbon filters + PC fans to help with solder smoke. Just for fun I modified this script to use a spiral for the filter holes. $fn=100; depth=10; //depth of lip and fins (10) platen=1.5; //thickness of platen (1.5) hole=platen+2; difference(){union(){ //platen cylinder(h=platen, d1=140, d2=140); //Main outer cylinder cylinder(h=depth+platen, d1=118, d2=118); } //internal cylinder translate([0,0,platen]) cylinder(h=depth+platen,d1=116,d2=116); //filter hole pattern phi = 1.618033988749895; pattern_spacing = 4.45; spiral_count = 57; base_angle = 30; for (i=[4:spiral_count])rotate([0, 0, base_angle + i*137.5]){translate([sqrt(i*phi)*pattern_spacing+4,0,-1])cylinder(h=hole, d1=10, d2=10);} translate([0,0,-1])cylinder(h=hole, d1=25, d2=25); } //anti turbulence fins difference(){for (i=[0:45:330])rotate([0, 0, i]){translate([46,-0.5,0])cube([12,1,depth+platen]);}}

Edible Robotics

I think this is a great project, I want one, which means I also want a 3D printer :-)

Dr Andy Hill

Will make one of these and give it a good test in my shed where I'm sure there's plenty of interesting things floating about it can nibble on.

Actually no need to buy, just recycle a fan from old PC or old PC power supply, the difference is they're usually 12V DC, just use a buck converter to lower the voltage and it become silent, I use M4 screw since it's fit the best, M3 feel a bit loose until screw it really tight. Maybe using M4 35mm or longer, can skip the 3D printing of the legs.

Johnson Lam

Very nice little project! I would love to see some kind of test of the effectiveness of ordinary tissue or toilet paper. Maybe by weighing it?

Andreas Schuderer

The fan is marked as a 5V fan with 12V voltage rating. Generic labels.

Big Clive

I toyed with that. If there was a common size it might be possible to make an adaptor.

Big Clive

I like it! Good stuff! I like the round one Maybe I'll try with alternate materials since I don't have a 3D printer.

Michael Thompson

Are the cabin air filters for cars good candidates for modeling something like this around? I think you can get them relatively cheap.

I do like the direction this project is taking. I'm going to play with it and print one off - as soon as I get a replacement board for my printer :P The weight/decorative ring - yes, the alignment pins would be nice, or you could make it like a cookie tin lid, so it fit over the body. That could also hide the corners of the paper sheet if it came down 10mm or whatever.

Charles

I am confused. You used a 12 volt wall wart but the fan says it is 5 volt.

Mark Trombley

You could put some UVC leds either above or below the fan for a little sanitation goodness or even just for some colour effect .. or even pop an air wick underneath to freshen up room. It is pretty insane though how much they charge for commercial air filters when a furnace filter and box fan will do pretty much do the same or better than top brands.

Peter Stevens

I love these sort of videos, filtration, ionization, Uv, ozone, Great stuff Clive!

Jeff Larson