fahnen_esp32/.pio/libdeps/esp01_1m/FastLED/examples/Audio/simple

Audio Reactive Visualization Example

This example demonstrates advanced audio reactive visualization capabilities using FastLED. It processes real-time audio input and creates stunning visual effects synchronized to music.

Features

Visualization Modes

1. Spectrum Analyzer - Classic frequency spectrum display with customizable colors
2. Waveform - Real-time audio waveform visualization
3. VU Meter - Traditional volume unit meter with RMS and peak indicators
4. Spectrogram - Scrolling frequency analysis over time
5. Combined - Split-screen showing both spectrum and waveform
6. Reactive Patterns - Dynamic patterns that respond to audio energy and beats

Audio Processing

• Real-time FFT - Fast Fourier Transform for frequency analysis
• Beat Detection - Automatic beat detection with adjustable sensitivity
• Auto Gain Control (AGC) - Automatically adjusts to varying audio levels
• Noise Floor Filtering - Removes background noise for cleaner visuals
• Attack/Decay/Sustain - Professional audio envelope controls

Visual Controls

• Multiple Color Palettes - Heat, Rainbow, Ocean, Forest, Lava, Cloud, Party
• Mirror Mode - Creates symmetrical displays
• Brightness Control - Adjustable LED brightness
• Fade Effects - Smooth transitions with adjustable fade time
• Color Animation - Animated color cycling with speed control
• Smoothing - Optional smoothing for less jittery displays

Advanced Features

• Frequency Band Analysis - 8-band frequency analyzer for detailed audio analysis
• FFT Smoothing - Temporal smoothing of frequency data
• Logarithmic Scale - Optional log scale for frequency display
• Freeze Frame - Pause the visualization at any moment
• Frame Advance - Step through frozen frames

UI Controls

Main Controls

• Enable Audio Reactive Mode - Master on/off switch for audio processing
• Visualization Mode - Dropdown to select visualization type

Audio Processing Group

• Fade Time - How quickly levels decay (0-4 seconds)
• Attack Time - How quickly levels rise (0-4 seconds)
• Output Smoothing - Final output smoothing (0-2 seconds)
• Audio Gain - Manual gain adjustment (0.1-5.0)
• Noise Floor - Background noise threshold (-80 to -20 dB)

Visual Controls Group

• Fade to Black - Trail/persistence effect (0-50)
• Brightness - LED brightness (0-255)
• Color Speed - Animation speed (0.1-5.0)
• Color Palette - Choose from 7 palettes
• Mirror Mode - Enable symmetrical display
• Smoothing - Enable temporal smoothing

FFT Controls Group

• Min Frequency - Lower frequency bound (20-1000 Hz)
• Max Frequency - Upper frequency bound (1000-20000 Hz)
• Logarithmic Scale - Use log scale for frequency
• FFT Smoothing - Smoothing factor (0-0.95)

Advanced Controls Group

• Freeze Frame - Pause visualization
• Advance Frame - Step forward when frozen
• Beat Detection - Enable beat detection
• Beat Sensitivity - Beat detection threshold (0.5-3.0)
• Auto Gain Control - Enable automatic gain adjustment

Hardware Setup

LED Configuration

• Default: 128x128 LED matrix (16,384 LEDs)
• Downscaled to 64x64 for output (4,096 LEDs)
• Data pin: GPIO 3 (configurable)
• LED type: WS2812B (Neopixel)

Audio Input

The example uses the FastLED audio system which can accept input from:

• Microphone (real-time audio capture)
• Audio file playback
• System audio (on supported platforms)

Usage

1. Basic Operation

   • Upload the sketch to your controller
   • Connect your LED matrix
   • Provide audio input
   • Use the web UI to control visualization

2. Optimizing for Your Setup

   • Adjust the noise floor if visualization is too sensitive/insensitive
   • Use AGC for varying audio levels
   • Tune beat sensitivity for your music style
   • Experiment with different color palettes and speeds

3. Performance Tips

   • Reduce matrix size for slower controllers
   • Disable smoothing for more responsive display
   • Use simpler visualization modes for lower CPU usage

Code Structure

Main Components

1. Audio Processing Pipeline

   AudioSample → FFT → Band Analysis → Beat Detection → Visualization
   

2. Visualization Functions

   • drawSpectrumAnalyzer() - Frequency spectrum bars
   • drawWaveform() - Audio waveform display
   • drawVUMeter() - Volume meter visualization
   • drawSpectrogram() - Time-frequency plot
   • drawReactivePatterns() - Beat-reactive patterns

3. Audio Analysis Classes

   • MaxFadeTracker - Smooth peak tracking with attack/decay
   • BeatDetector - Energy-based beat detection
   • FrequencyBandAnalyzer - 8-band frequency analysis

Customization

Adding New Visualizations

1. Create a new draw function
2. Add it to the visualization mode dropdown
3. Add a case in the main switch statement

Modifying Color Palettes

Edit the getCurrentPalette() function to add custom palettes.

Adjusting Frequency Bands

Modify the FrequencyBandAnalyzer constructor to change band boundaries.

Troubleshooting

• No visualization: Check audio input and ensure "Enable Audio Reactive Mode" is on
• Too dim/bright: Adjust brightness control
• Choppy animation: Increase smoothing or reduce matrix size
• No beat detection: Adjust beat sensitivity or check audio levels
• Visualization too sensitive: Increase noise floor value

Memory Requirements

This example requires significant memory for:

• Framebuffer: 128×128×3 = 49,152 bytes
• LED buffer: 64×64×3 = 12,288 bytes
• Audio buffers and FFT data

Platforms with limited memory may need to reduce the matrix size.