A Practical Open Source Air Purifier

January 16, 2024 by Jenny List 44 Comments

In the years since the start of the coronavirus pandemic, it’s fair to say we’ve all become a lot more aware of the air quality surrounding us. Many of us have added a CO₂ monitor to our collection of tools, and quite a few will have an air filtration system too. There are plenty of devices on the market that fulfill this niche at varying qualities and prices, but shouldn’t a decent filter be something to make for yourself? [Naomi Wu] thinks so, and she’s put up the design for her Nukit open air purifier online under the GPLv3.

The principle of the unit is simple enough: it’s a box with an HVAC filter on the front and a set of computer fans on its side to draw air through. But it’s more than just a box, as there are three separate versions for wall-mount, hanging mount or a freestanding tower, and each one comes as a DXF file with all parts ready for laser cutting. It’s about as straightforward a way to get your hands on a well-designed and high quality air purifier as could be imagined.

[Naomi] has been quiet for a while in her familiar role as YouTube maker and guide to the nooks and crannies of her native Shenzhen, so it’s very positive to see her still active and producing projects after being warned off social media by the authorities. If you’d like to see another recent project of hers, look no further than her update to [Bunnie Huang]’s Shenzhen guide.

Review: WAINLUX K8, A Diode Laser That’s Ready To Work

August 28, 2023 by Tom Nardi 24 Comments

Rarely a week goes by that some company doesn’t offer to send us their latest and greatest laser. You know the type — couple of aluminum extrusions, Class 4 diode flopping around in the breeze, and no enclosure to speak of unless you count the cardboard box they shipped it in. In other words, an accident waiting to happen. Such gracious invitations get sent to the trash without a second thought.

Now don’t get me wrong, I have no doubt that the average Hackaday reader would be able to render such a contraption (relatively) safe for use around the shop. Build a box around it, bolt on a powerful enough fan to suck the smoke out through the window, and you’ve turned a liability into a legitimate tool. But the fact remains that we simply can’t put our stamp on something that is designed with such a blatant disregard for basic safety principles.

The earlier WAINLUX JL4 — lucky rabbit foot not included.

That being the case, a recent email from WAINLUX nearly met the same fate as all those other invitations. But even at a glance it was clear that this new machine they wanted to send out, the K8, was very different from others we’d seen. Different even from what the company themselves have put out to this point. This model was fully enclosed, had a built-in ventilation fan, an optional air filter “sidecar”, and yes, it would even turn off the laser if you opened the door while it was in operation. After reading through the promotional material they sent over, I had to admit, I was intrigued.

It seemed like I wasn’t the only one either; it was only a matter of days before the Kickstarter for the WAINLUX K8 rocketed to six figures. At the time of this writing, the total raised stands at just under $230,000 USD. There’s clearly a demand for this sort of desktop laser, the simplicity of using a diode over a laser tube is already appealing, but one that you could actually use in a home with kids or pets would be a game changer for many people.

But would the reality live up to the hype? I’ve spent the last couple of weeks putting a pre-production WAINLUX K8 through its paces, so let’s take a look and see if WAINLUX has a winner on their hands.

Continue reading “Review: WAINLUX K8, A Diode Laser That’s Ready To Work” →

Open Source: Free As The Air You Breathe

September 20, 2022 by Al Williams 18 Comments

[Carolyn Barber] recently interviewed a 15-year-old who has been making Corsi-Rosenthal boxes for people in his community that are at risk for COVID. Not only is it great that a teenager has such community spirit, but it is also encouraging that [Richard Corsi] and [Jim Rosenthal] made an open-source design that can help people at a greatly reduced cost.

If you haven’t seen one of these boxes, it is essentially a box fan inside a cardboard box with MERV-13 filters on all sides. While these high-quality filters aren’t as efficient as HEPA filters, the box makes up for it by moving a prodigious amount of air and by being much less expensive. The article says you can build a unit for $60 to $100, which is considerably cheaper than other filters with similar performance.

There’s been at least one research paper on the efficacy of the filters and the results were generally quite positive. Schools are taking a great interest in these boxes because they are inexpensive and effective. Of course, the filters don’t last forever, but one of the creators estimates in a classroom with 25 students, a three-year run of the box would run about $4.46 per student per year. Not a lot to pay for clean air.

We love hearing about tech helping people and especially open source that makes big impacts. Usually, when we think of air filtering, we are thinking about laser cutters or 3D printers. However, we have seen inexpensive HEPA filters, too.

Nevermore Is What You Get When Engineers Design Air Filters For 3D Printers

September 3, 2022 by Donald Papp 25 Comments

What happens when an air filter for 3D printers gets designed by engineers with a passion for function, a refusal to compromise, and a desire to do without bad smells or fumes? You get the Nevermore, a design for a recirculating active-carbon filtration system to deal with VOCs (volatile organic compounds) from 3D printing.

3D-printable parts and an easy-to-fill chamber for bulk-activated carbon make this recirculating air filter for VOCs a smart, space-saving design.

The Nevermore Micro (and larger Nevermore Max) were originally intended to complement the Voron 3D printer design, but are made such that they can be used with just about anything else. These filters use 3D-printable parts, and are designed to be easily filled (and refilled) using bulk-activated carbon instead of some kind of proprietary pre-packed filter like most commercial offerings. The Voron project is all about a printer without compromises, and the Nevermore comes from that same design ethos.

A Nevermore filter sits inside the build chamber, and works by recirculating air inside while passing it through the activated carbon. The idea is that by concentrating on dealing with the problem at the source inside a relatively small build chamber, one doesn’t need a lot of airflow. A small recirculating air filter can do the job efficiently, though for best results, the build chamber should be as sealed as possible.

One interesting caution is that it seems not all activated carbon is the same, and it is absolutely crucial to use only acid-free, steam-activated (not acid-washed) carbon in a recirculating filter like the Nevermore. There are horrifying photos of oxidized metal surfaces resulting from using acid-residue carbon, some of which took only minutes to occur. Thankfully, there are pointers to trusted sources for the known-good stuff.

It’s known that 3D printing results in chemical and particle emissions. These differ significantly depending on both material and type of printer, but it’s enough of an issue to warrant attention. One deals with particulates with something like a HEPA filter, but VOCs require a carbon filter. This is where the Nevermore comes in. Active carbon filters will wear out simply from exposure to the air, so if one is serious about cleaning VOCs when printing, it is definitely worth looking into bulk carbon with a design like the Nevermore.

Air Filter DRM? Hacker Opts Out With NFC Sticker

August 13, 2022 by Donald Papp 55 Comments

[Flamingo-tech]’s Xiaomi air purifier has a neat safety feature: it will refuse to run if a filter needs replacement. Of course, by “neat” we mean “annoying”. Especially when the purifier sure seems to judge a filter to be useless much earlier than it should. Is your environment relatively clean, and the filter still has legs? Are you using a secondary pre-filter to extend the actual filter’s life? Tough! Time’s up. Not only is this inefficient, but it’s wasteful.

Every Xiaomi filter contains an NTAG213 NFC tag with a unique ID and uses a unique password for communications, but how this password was generated (and therefore how to generate new ones) was not known. This meant that compatible tags recognized by the purifier could not be created. Until now, that is. [Flamingo-tech] has shared the discovery of how Xiaomi generates the password for communication between filter and purifier.

A small NFC sticker is now all it takes to have the purifier recognize a filter as new.

[Flamingo-tech] has long been a proponent of fooling Xiaomi purifiers into acting differently. In the past, this meant installing a modchip to hijack the DRM process. That’s a classic method of getting around nonsense DRM on things like label printers and dishwashers, but in this case, reverse-engineering efforts paid off.

It’s now possible to create simple NFC stickers that play by all the right rules. Is a filter’s time up according to the NFC sticker, but it’s clearly still good? Just peel that NFC sticker off and slap on a new one, and as far as the purifier is concerned, it’s a new filter!

If you’re interested in the reverse-engineering journey, there’s a GitHub repository with all the data. And for those interested in purchasing compatible NFC stickers, [Flamingo-tech] has some available for sale.

DIY HEPA Fan Clears The Stale Office Air

January 20, 2021 by Kristina Panos 26 Comments

Although it would be nice, we can’t all work from home. If you have to spend the day in close quarters with other people, you might want more protection than just a mask and sanitizer. Check out [jshanna]’s DIY HEPA filtering fan — it looks like a breeze to build and uses commonly-available parts plus a few 3D-printed pieces to put it all together.

The basis of this attractive and useful office must-have is a muffin fan from Amazon that has an optional variable speed controller. A long threaded rod runs up the center of the HEPA filter, so it attaches kind of like a lampshade. The fan draws up air from underneath and blows it upward through the filter and out into the room. Whenever the HEPA filter gets dirty, just take it out and wash it.

Are you still buying disposable masks? You might save money in the long run by making your own.

3D Printing Air Filter System Does A Lot

January 14, 2021 by Al Williams 29 Comments

We know we aren’t supposed to eat a lot of sugar, but we still have ice cream. We also know we probably shouldn’t be inhaling solder smoke and 3D printer fumes, but we do that too. Not [Mike Buss]. His 3D printer has a major exhaust system.

We can sympathize with his process. He mentions he started out just wanting a fan running with some filters. Then he decided to add a way to turn the fan on and off when printing. Then he added sensors to detect fumes and fire. Data collection was almost an afterhthought.

Continue reading “3D Printing Air Filter System Does A Lot” →