To recap, my project is a tool for librarians to help manage the noise level in their library. I originally set out to build a tool that was automatic, which essentially would become the librarian itself. In my first iteration, I was still waiting on a part to arrive, the electret microphone. It was the only microphone I saw on Adafruit, so I assumed that it would be simple enough to use – there were only two wires.
The part came in, and I constructed my circuit, and in testing the microphone was only giving me a reading of 0.
I thought surely I had a wire misconnected, or there was an issue in my code somewhere. I was yelling into this tiny mike while taking readings, and occasionally it would jump up to 1, and once I saw a two, but I soon realized after yelling that it would still do this, which must have just been the natural oscillation/inconsistency of the reading. I began to research this more and I finally found out that you need a significant amount of power to boost the signal you get from a microphone. It needs to be amplified to a level that can be read by a microcomputer. A comment on the Arduino forum said:
“The idea is to amplify the signal from the microphone, which is in the millivolt range, to a level in the 0..5V range, that can be converted by an analog input of Arduino.”
This required a complex circuit with parts that I didn’t have, so I had to pivot on my idea. It still would have the same functionalities, but instead of being triggered automatically, the librarian would trigger them from her desk.
The Librarian would need to enter the IP address, and set up the required ports as outputs (“Initialize”).
If it’s too loud, they would hit the “Getting Too Loud” button and the red LED light would come on.
Once the children quiet down, the Librarian would hit the “That’s Better” button to turn off the LED.
If the children refuse to quiet down, the Librarian would have no choice but to turn on the “Silence Siren!!!” to out yell the children. They could control the tone played with the slider, to make it more irritating or less irritating depending on how they are feeling. Demonstration below: