Air filtration lampshade

thingiverse

This is a prototype air-filtering lampshade. We think of COVID as a respiratory illness, because it's airborne and the acute symptoms are related to the lungs, but it's increasingly clear that the long-term damage throughout the body ("long COVID", Post-COVID Condition / PCC etc) can be very significant, and in a significant-but-not-well-documented fraction of people it can last for at least years after the acute infection is over. We don't have data for longer periods - so maybe it magically disappears in year five, or maybe something worse happens, no-one knows. So you don't want to get it at all, but if you do the fewer times you get it, the less damage it will do (see below). Since COVID (and many other diseases) spread via exhaled aerosols, better ventilation is the obvious starting point. As many spaces have limited access to fresh outdoor air, filtration of indoor air to remove pathogens is going to need to become ubiquitous - the only question is how much harm will be done before we accept that. The well-known <a href="https://cleanaircrew.org/box-fan-filters/">Corsi-Rosenthal boxes</a> are very effective, easy to make, <a href="https://twitter.com/WBahnfleth/status/1469454061225316353">supported</a> by the experts, and in terms of air filtered per dollar spent I am not aware of anything better. That said, a number of people have been working on variants of the concept that are quieter, and integrate more unobtrusively into their surroundings. This one is meant as a proof-of-concept for an air filtering lampshade, that will fit into an existing stand lamp or pendant fixture. The visible surface of the lampshade is a hexagon made out of the filters themselves, although you could put a cover over it as long as air can flow through easily. As the filter surface is exposed (and I already know how fast stuff builds up), I oriented the airflow to go from fan to filter, so the dust collects on the less obvious inside face of the filters. It'll look nicer over time, but I'll have to dust off the fans periodically. The core is a hexagon of fans, which snap into the corner blocks in either orientation. If reversed to pull air in through the sides you could then see directly some of what the filters are keeping out of your lungs. Air can travel up and down the central shaft, and then the toroidal-ish space between the fans and the filters is enclosed top and bottom with clear heat-shrink film (that stuff you tape over your windows to improve the insulation, and then heat with a hair dryer until it goes taught and pulls the wrinkles out) to keep the air flowing where it needs to go but let the light through. Important to use an LED bulb, don't want the heat from an incandescent (both for effects on the heat-shrink material and also as a fire hazard). I'll upload STLs here for now, design was done in Fusion 360 and I am just hammering the bugs out of a parametric version that will allow the number and dimensions of the filters and fans to be changed arbitrarily. I'll upload that when it's done. I want to try one with the Arctic P14 fans as well. The fans can be powered from a second outlet, or from one of those light socket adapters that put a plug right next to the bulb. The <a href="https://www.ikea.com/ca/en/p/ansluta-led-driver-with-cord-white-90405845/">24V Ikea power supply</a> has 6 ports with a slightly weird shape to them but they are a perfect (clicks-into-place) fit for a 2-pin Dupont connector (with the caveat that you can insert it in either polarity). So I crimped connectors onto six <a href="https://www.digikey.ca/en/products/detail/sunon-fans/MF92252V1-1000U-A99/7652234">Digikey 259-1826-ND fans</a>, checked polarity with my multimeter and plugged them all in, and they run beautifully. These fans have good flow and static pressure for the price, and are reasonably quiet. The online specs say 1.8W, the fan says 1.92 on it, but anyway a bit under 12W total, and the power supply is rated for 19W (and has swappable plugs, input is rated to 240V, with an on-off switch on the cable). Six fans here, but any of the slots could be replaced with any of the Ikea lights in that ecosystem (<a href="https://www.ikea.com/ca/en/p/mittled-led-spotlight-dimmable-aluminium-colour-30453655/">this</a>, for example). All this is compatible with their home automation system, and they also make a PWM dimmer with remote in that product line as well (although these specific fans are <b>not</b> PWM-compatible). The fan corner blocks have bosses on them that snap into the mounting holes on the fans - a previous variant used hex bolts but I was using too many of them. They have two M3 holes on each end for the arms, eventually I'll try to get rid of those as well using a snap-fit arrangement. The filters are Ikea <a href="https://www.ikea.com/ca/en/p/uppatvind-filter-for-particle-removal-90551498/">Uppatvind</a>, which are rated EPA-12. The upper and lower (name refers to stand-lamp orientation, it'll be the other way around if used as a pendant) hex corners snap over the filters and the moulding. The horizontal moulding is 3/8" outside corner, the vertical has a cross-section like a half-round unioned with a flat strip - both from Home Depot. As you can see the heat shrink film worked out really well, and I am looking forward to integrating the concept into other projects as well. It's really hard to see on the image from underneath (but it is there), and then in the image from on top you can see the reflection of the bulb. I used 1.5 mil Frost King brand here (the extra strength outdoor kit for patio doors) but I suspect most brands would work. Some reviews online criticized the strength of the double sided tape that comes in the kit so I used Gorilla wall mounting tape. Still some cable management to be done, I'll probably print something that will hold the wires above the fans. It does plug in with the adapter (although a tight fit) and that puts everything inside the lampshade. More information on the COVID side of things: <ul> <li><a href="https://www.nature.com/articles/s41579-022-00846-2">Long COVID: major findings, mechanisms and recommendations</a> (Nat Rev Microbiol)</li> <li><a href="https://science.gc.ca/site/science/en/office-chief-science-advisor/initiatives-covid-19/post-covid-19-condition-canada-what-we-know-what-we-dont-know-and-framework-action">Post-COVID-19 Condition in Canada: What we know, what we don’t know, and a framework for action</a> (Office of the Chief Science Advisor of Canada)</li> <li>Some <a href="https://www.wired.com/story/the-teeny-tiny-scientific-screwup-that-helped-covid-kill/">background on why it has taken so long</a> to get public awareness of airborne spread</li> </ul>