So I had my first octave working and I put it in a music school for kids to play with it and have some feedback.

Actually the feedback was far better than expected, kids absolutely loved it.

The remarks were mostly on hardware design : basically the noise...

There was no protection between acrilyc and wood creating kind of tick-tick noise, the fact that all notes were separated were also adding to this each one touching others. 

The detection was a little bit odd sometimes (for adults, having the foot at 3cm of the note was already playing it where for younger children they had to remove their socks for it to work)

And biggest complaint from the kids, it was not big enough. Sometimes they were 3 kids on these 12 notes...

Overall the test was good: after 3 month of abuse by the kids, there was nothing broken and it was still in very good shape and working as day one.

Now I need to take this into account and move forward.