A clean, compact design for plugging-in an Amazon Echo Dot Gen 2 directly into an outlet..
Super lightweight: only 25 grams of plastic!!
A design that matches the Dot design somehow, with no visible wires, no ugly face clips blocking the light ring, no speaker obstruction. One piece, minimum plastic and prints without support. I did a bit of searching couldn't find any adapter (3d printed or commercial) meets all these criteria.
Body: I measured the Echo Dot and it turns out the diameter is tapered (at least the Gen 2 that I have is). That means it can be mounted inside a super compact ring with a perfectly tight fit, independent of the printer tolerances. An additional benefit of the ring mount is that it doesn't obstruct the sound in any way.
Power Adapter: For the DC adapter I needed both horizontal and vertical mount, initially I thought about doing the design parametric, but then realized it can be designed in one piece to fit both orientations (here the tolerances matter more here as there is a trade-off between the adapter getting stuck or being wobbly - if it turns out to be too tight, you can scale the entire design a bit (0.5-1%?),don't worry, the Dot ring is designed such that it can take the change in scale).
USB Cable: The cable that comes with Echo Dot is quite bulky, and while I made a cut-out that can accommodate it, in practice I found the assembly is quite tedious, so I found a short and 90-degree USB cable (this cable comes in a pair - Left and Right handed - both work here, but one works better and the other leaves the audio port accessible). There are probably better cables, even more compact, shorter and cheaper, I'll update the instructions when I find a better one.
Are there any flaws?
Sure, at least one: the Dot is not supported in the back, so be careful not to let it become unseated (maybe add a piece of support in the back?). I couldn't come up with a solution that would work for outlets of different heights (which I have already) without making it parametric and having to measure distance to wall, or without using screws (which would defeat the convenience of plugging and unplugging this.