I recently stayed in an apartment that didnt have central air so I created a corsi-rosenthal box since the smoke from the Canadian wildfires were so bad.
After 30 days of continuous use, with very minimal periods of it being turned off, this is what the filters look like!
It's disgusting yet also so satisfying to see the filters get darker from debris, dust, and dirt.
Edit: typos
There's also an open source tempest that you can use a CNC for and customize to your liking with a script. https://github.com/opennukit/Nukit-Open-Air-Purifier/tree/main/Nukit%20Open%20Air%20Purifier-W(all)%20v1.0
I have an unfinished project to make a nukit with a power knob.
I got a cardboard proof of concept working but need to make my mark 1 out of plywood or something else.
Duct tape an electrical knob device to the front and call it a day?