The original model wouldn't fit on my Prusa Mini, so I chopped off an end and modified it to fit a little less expensive hygrometer. You can still add desiccant to the tray for a proper dry box, but I recommend putting it in stainless steel shakers so that you can easily flash off the moisture in an oven every so often. The model requires 608 bearings.
The author remixed this model.
I shortened the tray, added some gussets, and reconfigured it for a rectangular hygrometer.