synth-core — no_std DSP library (oscillators, filters, envelopes, LFO, MIDI). Runs on microcontrollers and WASM.
synth-visualiser — browser-based visualiser (oscilloscope, spectrum analyser, patch bay) compiled to WebAssembly.

Prerequisites

# Rust toolchain (stable)
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

# WASM target
rustup target add wasm32-unknown-unknown

# wasm-pack (builds and packages the WASM module)
cargo install wasm-pack

Build

synth-core (native — tests and development)

cargo build -p synth-core
cargo test  -p synth-core

synth-core (WASM — verify it cross-compiles)

cargo build -p synth-core --target wasm32-unknown-unknown

synth-visualiser (browser)

Run from the workspace root:

wasm-pack build crates/synth-visualiser --target web --out-dir ../../www/pkg

This generates www/pkg/ containing the compiled .wasm binary and the JS glue module.

Run

Serve the www/ directory with any static HTTP server. A browser is required (the Web Audio API is not available over file://).

# Python (no install needed)
python3 -m http.server --directory www 8080

# Or with npx serve
npx serve www

Then open http://localhost:8080.

Microcontroller deployment

synth-core targets bare-metal Cortex-M out of the box. Add the relevant target and uncomment the linker flags in .cargo/config.toml.

# Example: Daisy Seed / STM32H750 (Cortex-M7)
rustup target add thumbv7em-none-eabihf
cargo build -p synth-core --target thumbv7em-none-eabihf

A microcontroller runner crate (I²S output, UART MIDI) can be added as a new workspace member when needed.

Project structure

sound/
├── crates/
│   ├── synth-core/          # no_std DSP library
│   │   └── src/
│   │       ├── oscillator.rs    VCO — Sine, Saw, Square, Triangle, Pulse
│   │       ├── filter.rs        SVF — LP / HP / BP / Notch
│   │       ├── envelope.rs      ADSR envelope generator
│   │       ├── vca.rs           Voltage-controlled amplifier
│   │       ├── lfo.rs           Low-frequency oscillator
│   │       ├── midi.rs          Byte-stream MIDI parser
│   │       ├── patch.rs         Cable routing graph
│   │       ├── math.rs          DSP utilities (lerp, dB, MIDI→Hz)
│   │       └── config.rs        SampleRate type
│   └── synth-visualiser/    # WASM browser front-end
│       └── src/
│           ├── engine.rs        AudioContext + AnalyserNode
│           ├── oscilloscope.rs  Time-domain canvas view
│           ├── spectrum.rs      FFT canvas view
│           ├── patchbay.rs      Drag-and-drop patch cables
│           └── params.rs        SynthParams (JSON serialisable)
└── www/
    ├── index.html           Browser UI
    ├── bootstrap.js         WASM loader (ES module)
    └── pkg/                 Generated by wasm-pack (git-ignored)