ScaleBridge

ScaleBridge is a local-first macOS menu bar app for collecting BLE scale measurements from supported eufy smart scales.

It watches for a scale in the background, connects when the scale wakes up, stores measurements and raw packets in SQLite, and opens the dashboard only when you ask for it from the menu bar.

Screenshots

Overview	History	Devices

Features

• Background BLE watcher for supported eufy scale profiles.
• macOS menu bar app with an on-demand Tauri window.
• Local SQLite storage for measurements, detected devices, and raw packets.
• Shared Rust core used by both the desktop app and debugging CLI.
• Raw packet capture for parser fixes and future device support.
• No cloud login, server sync, or official account API dependency.

Runtime Memory Usage

Measured on macOS 26.5 during the normal BLE scan cadence.

State	Included processes	Physical footprint	RSS
Background	App process and WebKit networking service	39 MB	108-109 MiB
Dashboard window open	App process, WebKit WebContent, GPU, and networking XPC	88-89 MB	201.8-202 MiB

Support Status

ScaleBridge is currently focused on the T9120 protocol family.

Device family	Status	Notes
eufy T9120	Confirmed	Live measurements have been verified on hardware.
eufy T9146 / T9147	Candidate	Expected to share the T9120-style profile, but not yet verified.
Other eufy BLE scales	Research	Devices and raw packets are logged so new profiles can be added without guessing.

See docs/protocol.md for the protocol notes and supported GATT profile details.

Getting Started

Requirements:

• macOS 13 or newer.
• Rust 1.85 or newer.
• pnpm 11.4.0 or newer.
• Xcode Command Line Tools.

Install dependencies:

pnpm install

Run the desktop app in development:

pnpm tauri:dev

Build the macOS app bundle and DMG:

pnpm tauri:build

CLI

The debugging CLI uses the same Rust BLE core as the desktop app.

Watch for scale events without writing a database:

cargo run -p scalebridge-cli -- watch --no-db

Watch and persist events to a local SQLite database:

cargo run -p scalebridge-cli -- watch --db ./scalebridge.sqlite

Parse a captured notification packet:

cargo run -p scalebridge-cli -- parse --hex "cf e8 12 b4 14 b3 b6 9f 00 00 0f"

Architecture

src/                         Tauri frontend and dashboard UI
src-tauri/                   macOS app shell, menu bar, autostart, commands
crates/scalebridge-core/     BLE scan/connect, GATT I/O, protocol parsing
crates/scalebridge-storage/  SQLite schema and repository layer
crates/scalebridge-cli/      Stdio debugging CLI
docs/                        Protocol and implementation notes

The frontend talks to the Rust backend through Tauri commands and events. BLE scanning, packet parsing, storage, and macOS integration stay on the Rust side.

Privacy

ScaleBridge is local-first. Measurements, device records, and raw BLE packets are stored on your Mac by default. The app does not require a cloud account and does not sync data to a server.

Documentation

• Implementation spec
• BLE protocol notes

License

Apache-2.0