Following up on Evan’s earlier work on this project, I have started designing v2 of our system. The primary focus of my designs is to make the system more self-contained and lower-maintenance. To that end, the design is centered around the ubiquitous 5-gallon plastic bucket. The large reservoir means fewer water changes and a nice, stable base (my system will be outside on a balcony, so wind is a concern).
I also wanted to refine the pump and bottle attachments so that they were sturdier and could be assembled quickly with basic tools. The key parts developed so far are:
Water Distribution Manifold
Three bottles fit on the bucket efficiently and I needed a way to distribute the water. This manifold connects the pump at the bottom of the bucket with three outlets on top of the lid. All of the plumbing will use the same 1”-8 thread and nut. The coarse thread is a good fit for 3D printing and is interchangeable with metal parts. If we were to manufacture kits, standard bolts and nuts could be used to test fit and clean up the printed parts. The manifold can be downloaded here: http://www.thingiverse.com/thing:869643
This fitting attaches a 2L bottle to a flat plate. The hole in the bottom is sized for a threaded fitting, though I won’t be using any in this project (the water will just flow out the hole into the bucket). The bottle holder can be downloaded here: http://www.thingiverse.com/thing:878942
The same ring that Evan used in the previous update will be used again in this version. The three rings will need to be held apart by a spacer which I still need to design. It can be downloaded here: http://www.thingiverse.com/thing:837700
I used this basket (http://www.thingiverse.com/thing:738791), as well. It really doesn’t print very well on an FDM machine like our RepRap Mendelmax, but it works and will be covered in expanded clay, anyway, so the imperfections won’t be visible.
The system will look pretty much like this when it is done. Evan's plants died since his last post, and we are hoping that the larger amount of water (5gal vs 1gal) in this new system will make the nutrient levels easier to manage.