The traffic light reminds me of SoundEar [1], noise monitors which were popular in Swedish classrooms fifteen years ago (and might still be). It worked well in

The traffic light reminds me of SoundEar [1], noise monitors which were popular in Swedish classrooms fifteen years ago (and might still be). It worked well in my seventh grade classroom. I'm not so sure about the red light being manual trigger only. I think it's better to decide objectively on what the desirable noise level should be. [1]: http://soundear.com/ http://soundear.com/