nice to read your post!
Yes your project helped me a lot and was my impression to build my own!
Unfortunately i didn't understand your code, because you wrote it in spanish.
So i wrote my own version of the code, which does basically the same than yours.
Yeah, the transformer is indeed ugly, i know...
I also thought about hiding it in a second hole.
As you can see i already damaged the wallpaper, so drilling another hole won't make it worse.
Currently i'm also thinking about to build a remote-switch (with one of these
enclosures) powered by an attiny and an IR-diode, which i want to mount near my bed.