Initial scaffold: Pi Multi-FX Pedal with NAM A2, IR cab, multi-FX, MIDI, stomp UI

2026-06-07 23:22:43 -04:00
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+# 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.