A combined desiccant and hygrometer holder that slips into the pour hole of the lid of a plastic dry goods box. I like this approach as it is neater than using baggies. With this setup, I can get internal humidity down to 10-15%.
Additional Materials (I bought from Amazon - not affiliated with any of them):
Wildone Cereal Storage Containers (6)
Tasogen 12 Pack Mini Digital Thermometer/Hygrometer
This is exactly what I was looking for. I didn't want to waste a bunch of filament putting something on the bottom for the spool to rotate on, and I wasn't going to use the filament from inside the cereal box. so, this works great for the humidity monitoring. Now I've got to get to work printing a whole bunch of them for my filament shelves. Thanks for the design.