A Dart package for reading data from Xiaomi Mi Scale v2 via Bluetooth Low Energy (BLE). This package provides a bridge to the Mi Scale 2 protocol and body composition calculations based on the reverse-engineered implementation from the openScale project.

• Mi Scale 2 Protocol Support: Complete implementation of the 5-step connection protocol
• Body Composition Calculations: Advanced metrics including body fat, water, muscle, bone mass, and visceral fat
• Multi-Unit Support: Handles kg, lbs, and catty weight units
• User Profiles: Gender, age, and height-specific calculations
• Data Validation: Robust parsing with date validation and error handling

Add this to your package's pubspec.yaml file:

dependencies:
  smartscale_reader: ^1.0.0

import 'package:smartscale_reader/smartscale_reader.dart';

// Create a user profile
const userProfile = MiScale2.UserProfile(
  gender: MiScale2.Gender.male,
  age: 30,
  height: 175.0, // cm
  scaleUnit: MiScale2.ScaleUnit.kg,
);

// Initialize MiScale2 instance
final miScale = MiScale2();

The Mi Scale 2 uses a 5-step connection protocol:

// Get connection steps for BLE communication
final connectionSteps = miScale.getConnectionSteps(userProfile);

// Step 0: Set scale units
// Step 1: Set current time  
// Step 2: Enable notifications (handled by your BLE layer)
// Step 3: Configure scale with user identifier
// Step 4: Request measurement data

// Parse 13-byte measurement data from BLE notification
final measurement = miScale.parseMeasurementData(bleData, userProfile);

if (measurement != null) {
  print('Weight: ${measurement.weight} kg');
  print('Date: ${measurement.dateTime}');
  print('Body Fat: ${measurement.bodyFat}%');
  print('Water: ${measurement.water}%');
  print('Muscle: ${measurement.muscle}%');
  print('Bone: ${measurement.bone} kg');
  print('Visceral Fat: ${measurement.visceralFat}');
}

final miScaleLib = MiScaleLib(
  gender: MiScale2.Gender.male,
  age: 30,
  height: 175.0,
);

const weight = 70.0; // kg
const impedance = 400.0; // ohms

final bmi = miScaleLib.getBMI(weight);
final bodyFat = miScaleLib.getBodyFat(weight, impedance);
final water = miScaleLib.getWater(weight, impedance);
final muscle = miScaleLib.getMuscle(weight, impedance);
final bone = miScaleLib.getBoneMass(weight, impedance);
final visceralFat = miScaleLib.getVisceralFat(weight);

• Weight Measurement History: 00002a2f-0000-3512-2118-0009af100700
• Weight Custom Service: 00001530-0000-3512-2118-0009af100700
• Weight Custom Config: 00001542-0000-3512-2118-0009af100700
• Body Composition Service: 0000181b-0000-1000-8000-00805f9b34fb
• Current Time: 00002a2b-0000-1000-8000-00805f9b34fb

The Mi Scale 2 sends 13-byte measurement packets:

• Bit 0 (Byte 0): LBS unit flag
• Bit 6 (Byte 1): Catty unit flag
• Bit 1 (Byte 1): Impedance available
• Bit 5 (Byte 1): Weight stabilized
• Bit 7 (Byte 1): Weight removed

The body composition calculations are based on reverse engineering of the Mi Body Composition Scale protocol. The algorithms take into account:

• Gender: Different coefficients for male/female
• Age: Age-specific adjustments for accuracy
• Height: Height-based calculations for lean body mass
• Weight: Current weight measurement
• Impedance: Bioelectrical impedance for body composition

• BMI: Body Mass Index
• Body Fat %: Percentage of body fat
• Water %: Body water percentage
• Muscle Mass: Lean muscle mass in kg
• Bone Mass: Bone mass in kg
• Visceral Fat: Visceral fat rating (1-59)
• LBM: Lean Body Mass in kg

• The package is based on the Java implementation from the openScale project
• Body composition algorithms are reverse-engineered from the Mi Fit app
• Date validation ensures measurements are within a reasonable time range
• Multi-user support through unique identifier generation
• Unit conversion handles kg, lbs, and catty measurements

• Dart SDK >=2.17.0
• Bluetooth Low Energy (BLE) support on target platform
• Compatible with Android/iOS through flutter_blue_plus or similar BLE packages

This package is released under the GPL-3.0 license, maintaining compatibility with the original openScale implementation.

Contributions are welcome! Please ensure any changes maintain compatibility with the Mi Scale 2 protocol and follow the existing code style.

• openScale project for the original Java implementation
• prototux for reverse engineering the Mi Body Composition Scale protocol