This device mounts an inexpensive hygrometer (see Aliexpress or Amazon) to an air tight screw top lid on a 5-gallon bucket. I used a food grade bucket so I can store food items or dog food when not storing filament. For my printer, I needed to scale up the STL file by 4% for the hygrometer to fit properly. My printer is not calibrated. I suggest printing the top millimeter or two on your printer to check the fit before printing the entire unit. To seal the hole, I used electrical putty sealant that I had. Tape would work if you are careful.

The bucket came from Lowes https://www.lowes.com/pd/Encore-Plastics-5-Gallon-General-Bucket/3694238

Airtight screwtop lid came from Lowes https://www.lowes.com/pd/Encore-Plastics-12-in-White-Plastic-Bucket-Lid/50094688

Eva-Dry renewable plug in dehumidifier such as https://www.eva-dry.com/product/e-250/ is used to maintain low humidity.

Cable clamps, https://www.thingiverse.com/thing:749228, were used. I scaled them up 150% to fit the self taping screws I had.

For a screw template, I flipped the mount over in my slicer (CURA) and lowered the model so that only a few layers printed on the bottom side. I use the several layers as the drill template for the screw alignment.

In all, not including filament, I spent around $26 on the entire project. That is about the cost of a roll of filament and will benefit print quality by keeping moisture out of your expensive filament.

I have downloaded many things (thanks to all), and this is my first contribution as one of the first things I designed.

Stay well.

Rich