A system design document has been linked to above; it can also be found here: https://docs.google.com/document/d/1FCr_1DzBJ3AlNbu3_3PSzmd7HQe7VcK2Rn7YlFluygg/edit?usp=sharing
It gives an overview of how the system works, as well as some of the technical details- how the software works, why design choices were made, etc.. It should eventually include technical[ish] drawings of the enclosure with dimensions and stuff. I don't have a good CAD package for doing that, so it'll probably be pictures taken from OpenSCAD with dimensions drawn on. It's pretty simple, though, so that should suffice.
Milling a lid is still in the works... I'm working to dial in my CNC mill for better aluminum cutting performance. And I still need to actually write the GCode. That's kind of important.