A native iOS app that bridges QN/Yolanda Bluetooth body-composition scales with Apple Health.

Step on your scale — ScaleBridge captures weight, body fat, muscle, water, BMI, bone, and more in one shot, writes them to Apple Health, and tracks your trends over time.

Screenshots

Features

Bluetooth pairing — auto-connects to QN/Yolanda smart scales (the same hardware used by many white-label apps)

Full body composition — 16 metrics: weight, body fat, muscle %, water %, BMI, lean mass, bone, protein, skeletal muscle, subcutaneous fat, visceral fat, muscle mass, BMR, metabolic age, health score, obesity degree

Apple Health sync — primary profile's readings flow into HealthKit automatically

Multi-profile — add a profile for each family member; the app logs to the right person based on weight

Range gauge — each metric shows a Low / Normal / High / Very High band with a goal hint ("Decrease by 4.3% to reach normal")

Trend charts — history view with per-metric charts across W / M / 6M / Y / All ranges

iOS 26 design — Liquid Glass tab bar, native system colors, SF Symbols throughout

Requirements

iOS 26+

Xcode 26+

A QN/Yolanda-compatible Bluetooth body-composition scale — tested with the HealthifyMe Smart Scale

Building

Clone the repo

Open ScaleBridge.xcodeproj in Xcode

Select your device as the build target (Bluetooth requires a real device)

Build & run — no third-party dependencies, no package manager needed

Body Composition Algorithms

The body composition formulas (body fat %, lean mass, BMR via Katch-McArdle, metabolic age) are derived from the openScale project. openScale is the reference open-source implementation for QN/Yolanda scale parsing and body composition math.

License

ScaleBridge is licensed under the GNU General Public License v3.0, consistent with its dependency on openScale (GPL v3).