UPDATE:

With some of the feedback regarding fittment issues, I've made an update that prevents larger spools from hitting the back of the container. This update also includes tappered rolers for self aligntment of spools, a lid and slight modifications to allow for a better fit of the tray and rollers into the container. Ive left the original files for those who prefer the older style. New files are labelled as V2.

Enjoy! 

With the original inspiration comming from:

I have made a few modifications to get a better fit and use round hygrometers. I also created a version inspired by the design by mathewsamuel. I've included STEP files if anyone else wants to make adjustments. Parts are listed below:

Parts:
Food storage containers: PRAKI Large Dry Food Storage Containers with Lids 4L (Amazon)

Hygrometers: OFFSCH 7pcs Round -Hygrometer Terrarium Mini Hygrometer (Amazon)

Bearings: 608 bearings

Filament tap fittings: Check thingiverse link

Bowden Tube: as required - no capricorn

Dessicant: Silica gel or 4A molecular sieve

Future Modifications:

Retraction drive from top of container for retracting filament manually when swapping filaments

Spool tensions system to reduce free “free spooling” when printing quickly.

Print Settings:
No supports are needed. Print at any height/infill you prefer. The tray version is basically the same amount of desiccant and is easier to print but uses a little more filament. I used PETG and havent had any issues. PLA is probably fine but the rollers may become a bit brittle over time with full spools.

Attribution:
Filament Tap: [https://www.thingiverse.com/thing:2139021](https://www.thingiverse.com/thing:2139021)