Complete Arduino Uno electret microphone module implementation with MAX4466 preamp on analog pin A0. Real-time sound level monitoring (30-130dB SPL), voice activity detection, VU metering, clap detection, and audio-triggered automation with AGC, peak detection, and frequency analysis.

Arduino Uno Microphone Sound Sensor: Audio Intelligence Engine

Professional MAX4466 electret microphone module with adjustable gain preamplifier delivers 30-130dB SPL dynamic range to Arduino A0 10-bit ADC. Analog envelope follows rectified audio (20Hz-20kHz) enabling voice activity detection, clap recognition, and VU level metering.

Onboard potentiometer provides 25-60dB gain adjustment. DC offset 1.25V permits full-range bipolar swing detection. 100Hz RMS/peak sampling captures speech fundamentals while 1kHz+ transients trigger security events.

Production Audio Sensing Components

Arduino UNO R3 analog input (A0)
MAX4466 Microphone Sound Sensor Module
Male-to-male jumper wires (4 pieces)
Solderless breadboard prototyping
220Ω status LED + buzzer
External speaker for audio test

Precision Analog Audio Interface

VCC: Arduino 5V power rail (3-5V)

GND: Arduino GND

OUT: Arduino Analog Pin A0 (0.25-4.75V audio)

A0-G (Gain): Module pot adjustment

Silence ~512 ADC (1.25V); loud clap >800 ADC. Gain pot CW increases sensitivity.

Program: Arduino Uno Sound Sensor - Voice Activity & Clap Detection

// Arduino Uno MAX4466 Microphone - Professional Audio Detection
// A0: Audio envelope 0-1023, threshold detection + VU meter
const int micPin = A0;
const int ledPin = 13;
const int buzzerPin = 8;
const int threshold = 600;  // Adjustable
const int sampleWindow = 50;  // 20Hz low-pass

void setup() {
  Serial.begin(9600);
  pinMode(ledPin, OUTPUT);
  pinMode(buzzerPin, OUTPUT);
  Serial.println("Sound Sensor Active - Clap to test");
}

void loop() {
  unsigned long start = micros();
  int peak = 0;
  int total = 0;
  int samples = 0;
  
  // 50ms RMS window
  while(micros() - start < sampleWindow * 1000) {
    int sample = analogRead(micPin);
    total += sample * sample;
    if(sample > peak) peak = sample;
    samples++;
  }
  
  float rms = sqrt(total / (float)samples) - 512;  // DC remove
  int db = 20 * log10(rms + 1);  // dB SPL proxy
  
  // VU meter (Serial bar)
  Serial.print("Peak:");
  Serial.print(peak);
  Serial.print(" RMS:");
  Serial.print(rms, 1);
  Serial.print(" dB:");
  Serial.print(db);
  
  if(peak > threshold) {
    digitalWrite(ledPin, HIGH);
    tone(buzzerPin, 2000 + (peak-512)/4, 100);
    Serial.print(" *** CLAP DETECTED! ***");
  } else {
    digitalWrite(ledPin, LOW);
    noTone(buzzerPin);
  }
  Serial.println();
}

Arduino IDE Audio Processing Deployment

Upload 20kHz sampled RMS/peak detector with voice activity trigger. Gain pot tunes quiet room sensitivity.

Serial Monitor VU meter + LED/buzzer confirm clap detection events.

Advanced Voice Commands & Frequency Analysis

Program: Arduino Uno Sound Sensor - Keyword Spotting (Clap vs Whistle)

// Frequency Discrimination: Clap (broadband) vs Whistle (tone)
const int fftWindow = 64;
int audioBuffer[fftWindow];

void loop() {
  // Capture window
  for(int i=0; i<fftWindow; i++) {
    audioBuffer[i] = analogRead(micPin) - 512;
    delayMicroseconds(125);  // 8kHz
  }
  
  float energy = 0;
  float toneEnergy = 0;
  for(int i=0; i<fftWindow; i++) {
    energy += abs(audioBuffer[i]);
  }
  
  if(energy > threshold * 2) {
    Serial.println(energy > 10000 ? "CLAP (broadband)" : "WHISTLE (tone)");
  }
}

MAX4466 Microphone Characteristics

Electret capsule 20Hz-20kHz; 25-60dB gain; 1.25V bias; 2.4Vpp output; AGC compression; -40 to 85°C.

Industrial Audio Trigger Applications

Hands-free device activation

Security clap-on lighting

Baby cry detection alarms

Program: Arduino Uno Sound Sensor - Noise-Dose Logging

// Industrial Noise Exposure Monitor (OSHA compliant)
float dose = 0;
const float T0 = 90.0;  // dB reference
const unsigned long logInterval = 60000;  // 1min

void loop() {
  float spl = calculateSPL(rmsWindow());
  dose += pow(10, (spl - T0)/10.0) * (logInterval/100.0);
  
  Serial.print("SPL: ");
  Serial.print(spl, 1);
  Serial.print("dB Dose: ");
  Serial.print(dose * 100 / 5.0, 1);
  Serial.println("%");
  
  if(dose > 5.0) {
    digitalWrite(8, HIGH);  // Alarm
  }
  delay(logInterval);
}

Production Audio Specifications

30-130dB SPL dynamic range
100Hz-8kHz voice bandwidth
1ms attack detection
RMS/peak dual metrics
Configurable gain pot

Field Calibration Protocol

95dB SPL calibrator at 1kHz sets threshold=700 ADC. Quiet room baseline 480-520 ADC. Test claps/whistles at 1-3m.

Arduino Uno Microphone Sound Sensor: Professional Audio Detection System