I read about this project a long time ago that used ultrasonic foggers to water plants, and now I'd like to do my own planters. After moderate success with a plastic tub that's got holes drilled in the lid, I'd like to make some custom containers.
The main issue with the boxes as currently designed is that they only can hold so much water before the foggers lose effectiveness, limiting them to being left alone for a week or so. In a larger container, people end up floating the fogger assembly to keep it at the optimum depth, but I wanted to try out something like those always-full pet dishes for a plant. That way, the reservoir can be significantly larger than the basin that's actually built into the planter, and it can be replaced quickly as a whole for easily controlled nutrition.
The design is two cylinders with a connecting tube that was slowly re-worked to make it easier to print on my home printer (MP Select Mini 200). The connecting tube was originally going to be cylindrical on top, but the overhang was too much for the printer, so I changed it to a 45 degree sloping peak instead of the arch. The threads are lifted off a Thingiverse cat water bowl (credits when I re-find it), and the base is designed to try to minimize leaks since those need to be sealed, and the finishing can be tedious.
All in all the design is a moderate success. I'll report more when I've got some root systems that close to the fogger unit in live plants for extended periods of time.
This was a fun romp through FreeCAD. I threw together a version 1 to test making watertight structures (and as an intro to FreeCAD). The trick, it seems, is to print slowly and with about 25% extra "width" in the slicer settings for the nozzle. That is, 0.5mm instead for an 0.4mm nozzle or 0.75mm for an 0.6mm nozzle. If it's making blobs of extra plastic, try dialing back the extra width. I printed my boxes in a combination of PLA and PET-G. The latter is a bit tricky because the layers sometimes don't stick together perfectly, causing leaks, but going slowly and turning the fan off helped a lot.