[Problem] with momentary switch


I got the arduino uno starter kit, and I'm trying to build project 7 - Keyboard instrument, which is pretty simple, but not working
well to me.

The circuit is as follow:

Now, I build this exactly (a few time, to verify myself).

The problem, is that:
when I push one of the momentary switch, the value that I see in the serial display (via A0 pin) is: 0,
except one switch: the bottom one. (then i get voltage).

Now I don't know how to check it, and what can be the problem.

I'll glad to a little bit help here.

Thank you all,

Hi and welcome.

Your posting is missing something.

You probably got a bunch of those cheap switches.
Those are easy to connect wrong.
So rotate that switch 90 degrees and see if that will do a better job.
Also check the wires are all good (change them to be sure).

Hello MAS 3!
I want to thank you for your answer.
Because of you I discovered that the problem is in the switch - they didn't match to the matrix connection.

The problem was solved.

Thank you again,