Well, the bad news is that this project will sleep until december because I have too many others things to do... ( especially at work... ).
I plan to produce some board in september for people interested. I will open some doodle at the beginning of september to build a list for that.
The current setup allow me to acquire some spectra and the results are good enough to reach the initial goal of this project.
Anyway, I'm still very interested in building a much more accurate device but, to be able to to this, I really need help for the optical setup.
The entire design is on github, don't hesitate to use / modify it !