Modular Air Filter

**Why make this?**
So an air filter is generally expensive, but the air filter cartridges themselves can be had fairly cheaply, in particular when they go on sale. If you want an air filter to use as a fume extractor when soldering, then one that just has a simple foam pad embedded with charcoal is enough to absorb VOCs. The more expensive filters can do that as well as filter out small dust particles. Both types of filters are great but generally (in my opinion) overpriced for what they are.

There are many types of designs to use PC fans with air filters cartridges - but I wanted to make one that was easy to print and assemble, with no supports required, that didn't look too dodgy, was modular so able to easily adapt to different types of cylindrical filters or fans, and the ability to add some smarts to it if desired.

So I needed plates for the top and bottom of the filter (these are the only things that may need replacing if changing to a different filter), a fan holder on top of