Electret Microphone Amplifier – MAX4466 with Adjustable Gain

 

The adafruit Electret Microphone Amplifier is an amplifier attached to a sound sensor which can be used to record audio, change voices, and any sound reactive projects like mine. These small amplifiers were perfect because they do not take up much space in the project but they are able to do a lot. They can adjust the amount of sound input and output to a voltage that the Arduino can detect. I did a lot of research regarding these sensors and learned how to adjust the volume and use them for sound reactive devices. The first step is to solder the header pins that come with the sensor to the OUT, GND, and VCC breakout pins. If you need help soldering refer to the soldering How-to on the website : http://etoolbox.org/tools/soldering-2/ . ‎Edit When soldering, be very careful not to leave the soldering iron on the metal for too long because to avoid frying the board. Once it has cooled, use wires to connect the sensor to an Arduino board: GND to ground, VCC to the VCC pin (2.4-5V), and OUT to an analog pin. On the back of the board is a small trick pot (labeled below). Use a screwdriver to gently turn it to adjust the gain based on how loud the sounds you are inputing are. If you don’t adjust the gain, the sound wave could clip, altering your results. When I was doing this, I had to play around with the gain for a few classes before I finally found the perfect setting. If you are using multiple sensors, not all of them will work on the same setting, they will probably need to be turned different amounts. This is all of the hardware you need to set up before beginning your code.

 

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When writing your code, keep in mind that the sound is measured through the analog pins, so it is a sound wave. When a loud sound is sensed, the Arduino will read either a very high or very low value from 0-1023. If you are making an audio reactive project, you must write in the code that when a loud sound is sensed, some other component will complete an action. For example, if you wanted to turn an LED on when a sound is sensed:

if (sensorValue < 300 || sensorValue>700)         // If sound wave is at its extremes (loud sound)

{

digitalWrite (RedLED, HIGH); // Turn red LED on

}

 

The most important thing is to keep trying and never give up! Be fearless!!

GOOD LUCK!!!!!

Written by Tamar Kellner Class of 2018

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