MAX4466 - Adafruit Electret Microphone

What is the Adafruit Electret Microphone and MAX4466?

Electret Microphone and MAX4466 Amplifier
Front Side Back Side

The Electret microphone amplifier breakout board comes with a 20-20KHz electret microphone soldered on. For the amplification, the board uses the Maxim MAX4466, an op-amp chosen for power supply noise rejection. On the back, there is a small trimmer pot to adjust the gain from 25x to 125x. The output is a rail-to-rail analog voltage signal that ranges from 200mVpp (for normal speaking volume about 6" away) up to 1Vpp, which is ideal for the mbed's on board ADC. The board uses an input power of 2.4-5VDC. Best performance is observed when using a supply with low noise, 3.3V on the mbed. This breakout is best used for projects such as voice changers, audio recording/sampling, and audio-reactive projects that use FFT.

Wiring Your Microphone

Below is a table showing an example pinout for the MAX4466. VCC should be connected to 3.3V. GND should be connected to the common ground. OUT should be connected to an "AnalogIn" pin on the mbed(p15-p20).


Our Pic


Import libraryMAX4466

This library sets up and LED volume indication function and reading values from the Electret Microphone - MAX4466 Amplifier

Hello World

Import programMAX4466_Hello_World

This hello world utilizes the basic functions setup in the MAX4466 library to indicate volume levels read from the microphone using the 4 LEDs built in to the MBED


#include "mbed.h"
#include "MAX9814.h"
Serial pc (USBTX, USBRX);

MAX9814 mic(p20);

int main()
    while (1) {
        pc.printf("\n\r Level is %f", mic.sound_level());


1 comment on MAX4466 - Adafruit Electret Microphone :

04 Feb 2016

Hi Matthew... I am using your code to configure a microphone to measure sound levels on the FRDM KL46z. I wanted to ask you why you chose "1024" in calibration and measurement functions. You are using the LPC1768 which has a 12-bit ADC, so shouldn't you be using 2^12 as the minval ? Also could you help me setting up the microphone on the KL46z

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