MAX9814 AGC Electret Microphone Amplifier Module — Analog OUT | ESP32 WLED Audio Reactive | Arduino Compatible

Upgrade your audio-reactive projects with the MAX9814 Electret Microphone Amplifier Module, featuring Automatic Gain Control (AGC) for clean, stable sound detection. Whether you're building WLED music-reactive LEDs, Arduino sound sensors, or ESP32 audio visualization, this module delivers professional audio performance in a compact form.

With automatic gain, the MAX9814 adjusts its sensitivity on-the-fly — perfect for environments where sound levels constantly change.

Top Features

Perfect For

Wiring Diagram 

Typical wiring:
  MAX9814 VCC -> ESP32 3.3V
  MAX9814 GND -> ESP32 GND
  MAX9814 OUT -> ESP32 ADC1 (GPIO34 recommended)

SEO Keywords

MAX9814, electret microphone module, AGC microphone, audio reactive, WLED microphone, ESP32 audio input, analog microphone sensor, Arduino sound sensor, music reactive LED, microphone amplifier board.

Arduino (ESP32) Sketch — MAX9814 → WLED (HTTP)

Click to expand Arduino sketch 
/*
ESP32 + MAX9814 -> compute RMS audio level -> send to WLED (HTTP)
Connect: MAX9814 OUT -> GPIO34 (ADC1_CH6), VCC->3.3V, GND->GND
*/

#include <WiFi.h>
#include <HTTPClient.h>

const char* ssid = "YOUR_WIFI";
const char* pass = "YOUR_PASS";
const char* WLED_IP = "192.168.1.50"; // replace with your WLED device IP

const int MIC_PIN = 34;      // ADC1 (GPIO34) recommended
const int ADC_SAMPLES = 250; // tune for responsiveness
const int SAMPLE_DELAY_US = 200;

const float RMS_MIN = 6.0;   // noise floor (tune)
const float RMS_MAX = 150.0; // loud signal (tune)

float readRMS() {
  const int MID = 2048;
  unsigned long sum = 0;
  for (int i = 0; i < ADC_SAMPLES; i++) {
    int raw = analogRead(MIC_PIN);
    int centered = raw - MID;
    sum += (unsigned long)centered * (unsigned long)centered;
    delayMicroseconds(SAMPLE_DELAY_US);
  }
  float mean = (float)sum / ADC_SAMPLES;
  return sqrt(mean);
}

uint8_t rmsToBrightness(float rms) {
  float norm = (rms - RMS_MIN) / (RMS_MAX - RMS_MIN);
  norm = constrain(norm, 0.0, 1.0);
  return (uint8_t)(norm * 255.0);
}

void sendWledHTTP(uint8_t bri) {
  if (WiFi.status() != WL_CONNECTED) return;
  HTTPClient http;
  String url = String("http://") + WLED_IP + "/json/state";
  http.begin(url);
  http.addHeader("Content-Type", "application/json");
  String payload = "{\"on\":true,\"bri\":";
  payload += String(bri);
  payload += "}";
  http.POST(payload);
  http.end();
}

void setup() {
  Serial.begin(115200);
  WiFi.begin(ssid, pass);
  Serial.print("Connecting WiFi");
  while (WiFi.status() != WL_CONNECTED) { delay(300); Serial.print("."); }
  Serial.println(" connected");
}

void loop() {
  float rms = readRMS();
  uint8_t bri = rmsToBrightness(rms);
  Serial.printf("RMS: %.1f -> bri: %d\n", rms, bri);
  sendWledHTTP(bri);
  delay(60);
}

ESPHome Configuration — ADC → WLED

Click to expand ESPHome YAML 
esphome:
  name: audio_to_wled
  platform: ESP32
  board: esp32dev

wifi:
  ssid: "YOUR_WIFI"
  password: "YOUR_PASS"

logger:
api:
ota:

http_request:

sensor:
  - platform: adc
    pin: GPIO34
    name: "Mic Raw ADC"
    id: mic_raw
    update_interval: 50ms
    attenuation: 11db
    filters:
      - sliding_window_moving_average:
          window_size: 8
          send_every: 1

  - platform: template
    name: "Audio Brightness"
    id: audio_bri
    update_interval: 100ms
    lambda: |-
      float raw = id(mic_raw).state;
      const float in_min = 20.0;   // tune empirically
      const float in_max = 500.0;  // tune empirically
      float v = (raw - in_min) / (in_max - in_min);
      if (v < 0) v = 0;
      if (v > 1) v = 1;
      return (int)(v * 255.0);

interval:
  - interval: 100ms
    then:
      - lambda: |-
          int b = (int) id(audio_bri).state;
          char payload[64];
          snprintf(payload, sizeof(payload), "{\"on\":true,\"bri\":%d}", b);
          id(http_request).post("http://WLED_IP/json/state", "application/json", payload);

What You Receive

Important notes: For reliable ADC sampling use an ESP32 "classic" (ADC1 pins) and power the MAX9814 from 3.3V. Tune RMS_MIN/RMS_MAX or ESPHome mapping after observing raw ADC readings in your environment.

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