Microphone Amplifier Module GY-MAX4466

Features:

• Wide Supply Voltage Range: The module operates effectively within a supply voltage range of +3.3V to +5.5V, providing flexibility and compatibility with various power sources.
• Electret Microphone Integration: Seamlessly combines with an electret capsule microphone, optimizing the amplification process specifically for microphone applications.
• Adjustable Gain Flexibility: The module offers adjustable gain settings, allowing precise control over the amplification level, catering to diverse audio input requirements.
• Exceptional Power-Supply Rejection: With an outstanding power-supply rejection ratio of 112dB, the module efficiently suppresses any undesired fluctuations or noise from the power source, contributing to a cleaner audio signal.
• Superior Common-Mode Rejection: The impressive common-mode rejection ratio of 126dB ensures that any common-mode signals, often originating from external interference, are greatly attenuated, preserving the integrity of the microphone signal.
• High Amplification Voltage Gain: Featuring a high AVOL (amplification voltage gain) of 125dB with a load resistance of 100kΩ, the module offers significant signal amplification capabilities, resulting in improved signal strength.
• Rail-to-Rail Output Operation: The module's rail-to-rail outputs ensure that the amplified signal can swing from the lowest to the highest possible voltage levels within the supply range, maximizing dynamic range.
• Low Quiescent Supply Current: With a mere 24µA quiescent supply current, the module operates with minimal power consumption, ideal for applications where energy efficiency is essential.
• Impressive Audio Quality: The module is designed to deliver excellent sound quality, preserving the nuances of the microphone's input signal, thereby ensuring accurate and clear audio reproduction.
• Wide Gain Bandwidth: With a gain bandwidth of 600kHz when AV ≥ 5 (as in MAX4466/MAX4468), the module maintains its amplification capabilities across a broad range of frequencies, supporting various audio applications.

Principle of Work:

The Microphone Amplifier Module GY-MAX4466 is a versatile tool for amplifying electret microphone signals. It provides adjustable gain, compatibility with various devices, and the flexibility to integrate it with microcontroller-based projects, making it suitable for a wide range of audio applications.

For audio-responsive projects, using an FFT driver library is highly recommended to convert audio input signals into frequency components.

How It Works

1. Microphone Input: Captures sound waves via an electret microphone and converts them to electrical signals.
2. Amplification Circuit: Uses the MAX4466 operational amplifier tailored for microphone signals to amplify weak inputs.
3. Adjustable Gain: Allows precise control over the amplification factor to suit different audio levels.
4. DC Bias: Outputs a DC bias around half the supply voltage when silent, useful for certain audio processing.
5. AC Coupling: Add a 100µF capacitor on output to block DC bias if your system requires AC-coupled input.
6. Audio Output: The amplified analog audio signal is available at the OUT pin.
7. Compatibility: Suitable for headphones and audio amps with proper input; larger speakers need external amplification.
8. Microcontroller Interface: Connect directly to ADC input pins for digital audio processing without extra hardware.
9. Audio-Responsive Projects: Use with FFT libraries to analyze frequency data and create dynamic effects.

Pinout of the Module

• VCC: Power supply input (3V to 5.5V)
• GND: Ground connection
• OUT: Analog amplified audio output signal

Applications

• Audio recording and sampling with improved sound clarity
• Real-time audio analysis and visualization using FFT libraries
• Audio-reactive projects such as sound-responsive LED displays
• Sound detection and monitoring for security or noise alert systems
• Educational demonstrations of analog signal amplification and microcontroller interfacing
• DIY audio equipment like mixers, amplifiers, and portable recorders
• Home automation with audio-triggered commands
• Electronic music instruments responding to sound input
• Environmental sensing enhanced by audio data
• Speech recognition systems requiring clear audio input
• Interactive art installations reacting to sound

Basic Circuit Connection with Arduino

1. Connect module GND to Arduino GND.
2. Connect module VCC to Arduino 5V.
3. Connect module OUT to Arduino analog pin A0.

Gain Adjustment

Use a small flat-head screwdriver to turn the onboard trimmer potentiometer to adjust the gain between 25x and 125x, optimizing the module for your specific audio input levels.

Arduino FFT Code Example

#include "ArduinoFFT.h"

const int sensorPIN = A0;
const int sampleWindow = 50; // ms
const double samplingFrequency = 1000.0 / sampleWindow; // Hz
const int samples = 128;

double vReal[samples];
double vImag[samples];

ArduinoFFT FFT = ArduinoFFT();

void setup() {
  Serial.begin(9600);
}

void loop() {
  unsigned long startMillis = millis();
  unsigned int signalMax = 0;
  unsigned int signalMin = 1024;
  unsigned long totalSample = 0;

  for (int i = 0; i < samples; i++) {
    unsigned int sample = analogRead(sensorPIN);
    totalSample += sample;
    vReal[i] = (double)sample;
    vImag[i] = 0;

    if (sample > signalMax) signalMax = sample;
    if (sample < signalMin) signalMin = sample;

    delayMicroseconds(1000 / samplingFrequency);
  }

  double avgSample = (double)totalSample / samples;
  unsigned int peakToPeak = signalMax - signalMin;
  double volts = (peakToPeak * 5.0) / 1024;

  Serial.print("Amplitude: ");
  Serial.print(volts, 2);
  Serial.print(" V\tAverage: ");
  Serial.println(avgSample, 2);

  FFT.Windowing(vReal, samples, FFT_WIN_TYP_HAMMING, FFT_FORWARD);
  FFT.Compute(vReal, vImag, samples, FFT_FORWARD);
  FFT.ComplexToMagnitude(vReal, vImag, samples);

  // Frequency spectrum analysis can be done using vReal[]

  while (millis() - startMillis < sampleWindow);
}

Technical Specifications

• Supply voltage: +2.4V to +5.5V
• Power-supply rejection ratio: 112dB
• Common-mode rejection ratio: 126dB
• Voltage gain (AVOL): 125dB (with 100kΩ load)
• Module size: 15mm × 9mm

Module Comparison

Note: MAX4466’s output bias and voltage range may cause clipping with louder sounds if gain is set too high.