# Pi Multi-FX Pedal 🎸

A real-time guitar multi-FX pedal running on **Raspberry Pi 4B** with:

- **NAM A2** neural amp modeling — load and switch between capture profiles
- **IR cab simulator** — impulse response convolution for cabinet simulation
- **Multi-FX chain** — noise gate, compressor, overdrive/distortion, EQ, modulation (chorus/flanger/phaser/tremolo), delay, reverb
- **MIDI in/out** — foot controller, expression pedal, preset switching via Program Change
- **Stomp-friendly UI** — footswitches, RGB LEDs, OLED display, tuner

## Architecture

```
Guitar → I2S ADC → JACK Audio → DSP Pipeline → I2S DAC → Amp/Headphones
                               │
                    ┌──────────┴──────────┐
                    │    NAM LV2 Plugin   │
                    │   (neural amp sim)  │
                    ├─────────────────────┤
                    │   IR Convolver LV2  │
                    │   (cabinet sim)     │
                    ├─────────────────────┤
                    │   LV2 FX Chain      │
                    │   (mod/delay/verb)  │
                    └─────────────────────┘
```

## Signal Chain

```
Input → Gate → Comp → Boost → NAM Amp → IR Cab → EQ → Mod → Delay → Reverb → Volume → Output
         │       │       │        │         │      │    │      │       │        │        │
         │       │       │        │         │      │    │      │       │        │        │
    ┌────┴───┐ ┌─┴──┐ ┌──┴───┐ ┌─┴─────┐ ┌──┴──┐ ┌─┴──┐ ┌──┴──┐ ┌───┴──┐ ┌───┴──┐ ┌──┴───┐
    │Noise   │ │Dyn │ │Drive │ │Neural │ │IR   │ │EQ  │ │Mod  │ │Delay │ │Reverb│ │Master│
    │Gate    │ │Comp│ │Boost │ │Amp    │ │Cab  │ │     │ │     │ │      │ │      │ │Volume│
    └────────┘ └────┘ └──────┘ └───────┘ └─────┘ └────┘ └─────┘ └──────┘ └──────┘ └──────┘
```

## Hardware

| Component | Spec |
|-----------|------|
| **SBC** | Raspberry Pi 4B (2GB+ RAM) |
| **Audio I/O** | I2S DAC + ADC (e.g. PCM1808 + PCM5102, or an Audio HAT) |
| **Footswitches** | 3-6 momentary soft-touch (e.g. MXR-style) |
| **LEDs** | RGB WS2812B or APA102 per footswitch + status LEDs |
| **Display** | 128x64 OLED SSD1306 (I2C) or small TFT |
| **MIDI** | 5-pin DIN in/out via UART + optoisolator |
| **Power** | 5V/3A USB-C (with buck for 3.3V rail) |
| **Enclosure** | 1590BB or 3D-printed custom |

## Project Structure

```
├── src/
│   ├── dsp/              Audio processing pipeline
│   │   ├── pipeline.py   FX chain orchestration
│   │   ├── ir_loader.py  IR convolution engine
│   │   ├── nam_host.py   NAM model loading & inference
│   │   └── level.py      Input/output level + tuner
│   ├── midi/             MIDI subsystem
│   │   ├── handler.py    MIDI event parse & dispatch
│   │   └── presets.py    PC → preset mapping
│   ├── ui/               Hardware UI layer
│   │   ├── footswitch.py Debounced GPIO input
│   │   ├── leds.py       RGB LED controller
│   │   └── display.py    OLED display manager
│   ├── presets/          Preset system
│   │   ├── manager.py    Save/load/bank/preset CRUD
│   │   └── types.py      Preset & chain data model
│   └── system/           System integration
│       ├── audio.py      ALSA/JACK/I2S configuration
│       └── setup.py      First-boot setup scripts
├── scripts/              Build & utility scripts
├── tests/                Tests
├── docs/                 Documentation
└── hardware/             KiCad/PCB schematics
```

## Development Quick Start

```bash
# Clone
git clone https://gitea.ourpad.casa/shawn/pi-multifx-pedal.git
cd pi-multifx-pedal

# Install dependencies
pip install -r requirements.txt

# Run tests
python -m pytest tests/ -v
```

## Status

Early development — initial scaffold.