Sound Visualizer

Sound Visualizer

Image: DIY Arduino LED screen for audio spectrum analyzer 1.jpg by Retired electrician via Wikimedia Commons, CC0

How It Works

• A microphone module (with a built-in amplifier, such as the MAX9814 or a simple electret+op-amp board) outputs a fluctuating analog voltage proportional to sound amplitude.
• The Arduino samples this analog signal repeatedly and computes a rolling amplitude/intensity level.
• That intensity level maps to how many LEDs light up (on a strip) or which pattern is shown (on a matrix), updated continuously as the sound changes.
• Optional smoothing/averaging avoids the display flickering erratically on brief spikes.

Components

Arduino Uno/Nano
Microphone module with amplifier (MAX9814 or similar)
Addressable LED strip (WS2812B) or 8x8 LED matrix
Power supply (LED strips can draw significant current)

Applications

• Music visualization displays
• Ambient room lighting that reacts to sound
• Teaching analog signal sampling and real-time processing

Advantages

• Visually engaging, immediate feedback makes for a strong project demo
• Introduces analog signal sampling and smoothing techniques
• Works with any ambient sound source, no special audio input needed

Sample Code — Amplitude-to-LED Mapping

// Simplified sound visualizer - Arduino + WS2812B
#include 
#define NUM_LEDS 30
#define LED_PIN 6
CRGB leds[NUM_LEDS];
int micPin = A0;

void setup() {
  FastLED.addLeds(leds, NUM_LEDS);
}

void loop() {
  int level = analogRead(micPin);
  int litCount = map(level, 0, 1023, 0, NUM_LEDS);

  for (int i = 0; i < NUM_LEDS; i++) {
    leds[i] = (i < litCount) ? CHSV(i * 8, 255, 255) : CRGB::Black;
  }
  FastLED.show();
}

Related Research

• Music Reactive LED using Arduino Nano — ResearchGate