A learning and practical indicator that visually shows the noise level in the room using the well-known colors of the traffic light.The apparatus is ideal for classrooms, kindergartens, special or educational environment where a certain level of silence and concentration should be maintained.Works by measuring the sound in the room and automatically shows the result with colour indication:
- Green: low noise and peaceful environment;
- Yellow: moderate noise level;
- Red: high noise level, which is recommended to reduce for better concentration and organization of the group.This visual indicator makes the sound 
