Instructables user pstretz made this Arduino-based simple soft tone generator for another user (carmitsu) who wrote:

I teach music in elementary school. We play a lot of recorder music. i.e. the kids play little flutes…… I have several special needs kids who can are using these black poster boards with circles that have the name of the note on them. These students push on the circles with notes names at the same time the rest of the students are playing a song….. Most of the special needs kids can do this fairly well and in time with the music.

What I am looking to to is build a very simple sound generator so that these kids could play the same pitch as those being played by the students on their recorders. I would only be a few pitches. I thought I could attach some kind of small button to the bottom of their round circles so that when they push on them the sound would come out of a small speaker, loud enough so they could hear.

And that’s just what this is, a simple tone generating soft circuit. It’s a great simple project to make, and it warms my heart to see makers helping teachers helping kids.