If there's one thing that makes teaching difficult, it's a noisy group of students - and usually the definition of noisy varies between the two sides. This problem has been solved nicely by Eric Harris-Braun who has created a device that can measure sound levels, display them on an LCD - and once the sound level exceeds a pre-determined level, a strip of LEDs are illuminated to warn the student that they're too loud. The microphone and Arduino can sit at one end of the classroom, and the LED strip is controlled remotely via infra-red, which lets you place it near the students. What a great idea. Eric runs through his design in the following video:
To test audio sampling yourself you can make an easy start with a simple electret microphone board, and our Freetronics MIC: microphone and sound module is perfect.
The MIC: contains an integrated dual signal amplifier converts the sound to separate channels for pulse / frequency measurement, and sound volume (pressure) level. Designed to connect straight to an Arduino compatible microcontroller, Analog to Digital converter, or many other circuits. For more information and to order click here.