Synheart Wear

Unified wearable SDK for Flutter — Stream HR, HRV, steps, calories, and distance from Apple Watch, Fitbit, Garmin, Whoop, and Samsung devices with a single, standardized API.

✨ Features

🚀 Quick Start

Installation

dependencies:
  synheart_wear: ^0.2.1

flutter pub get

Basic Usage

import 'dart:io';
import 'package:flutter/widgets.dart';
import 'package:synheart_wear/synheart_wear.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  // Initialize SDK
  final adapters = <DeviceAdapter>{
    DeviceAdapter.appleHealthKit, // Uses Health Connect on Android
  };

  final synheart = SynheartWear(
    config: SynheartWearConfig.withAdapters(adapters),
  );

  // Request permissions & initialize
  await synheart.requestPermissions(
    permissions: {
      PermissionType.heartRate,
      PermissionType.steps,
      PermissionType.calories,
    },
    reason: 'This app needs access to your health data.',
  );

  await synheart.initialize();

  // Read metrics
  final metrics = await synheart.readMetrics();
  print('HR: ${metrics.getMetric(MetricType.hr)} bpm');
  print('Steps: ${metrics.getMetric(MetricType.steps)}');
}

Real-Time Streaming

// Stream heart rate every 5 seconds
synheart.streamHR(interval: Duration(seconds: 5))
  .listen((metrics) {
    final hr = metrics.getMetric(MetricType.hr);
    if (hr != null) print('Current HR: $hr bpm');
  });

// Stream HRV in 5-second windows
synheart.streamHRV(windowSize: Duration(seconds: 5))
  .listen((metrics) {
    final hrv = metrics.getMetric(MetricType.hrvRmssd);
    if (hrv != null) print('HRV RMSSD: $hrv ms');
  });

📊 Data Schema

All data follows the Synheart Data Schema v1.0:

{
  "timestamp": "2025-10-20T18:30:00Z",
  "device_id": "applewatch_1234",
  "source": "apple_healthkit",
  "metrics": {
    "hr": 72,
    "hrv_rmssd": 45,
    "hrv_sdnn": 62,
    "steps": 1045,
    "calories": 120.4,
    "distance": 2.5
  },
  "meta": {
    "battery": 0.82,
    "firmware_version": "10.1",
    "synced": true
  }
}

Access in code:

final metrics = await synheart.readMetrics();
print(metrics.getMetric(MetricType.hr));        // 72
print(metrics.getMetric(MetricType.steps));     // 1045
print(metrics.getMetric(MetricType.distance));  // 2.5
print(metrics.batteryLevel);                     // 0.82

📚 Full API Documentation | Data Schema Details

⌚ Supported Devices

⚙️ Platform Configuration

Android

Add to android/app/src/main/AndroidManifest.xml:

<!-- Health Connect Permissions -->
<uses-permission android:name="android.permission.health.READ_HEART_RATE"/>
<uses-permission android:name="android.permission.health.WRITE_HEART_RATE"/>
<uses-permission android:name="android.permission.health.READ_HEART_RATE_VARIABILITY"/>
<uses-permission android:name="android.permission.health.WRITE_HEART_RATE_VARIABILITY"/>
<uses-permission android:name="android.permission.health.READ_STEPS"/>
<uses-permission android:name="android.permission.health.WRITE_STEPS"/>
<uses-permission android:name="android.permission.health.READ_ACTIVE_CALORIES_BURNED"/>
<uses-permission android:name="android.permission.health.WRITE_ACTIVE_CALORIES_BURNED"/>
<uses-permission android:name="android.permission.health.READ_DISTANCE"/>
<uses-permission android:name="android.permission.health.WRITE_DISTANCE"/>

<!-- Health Connect Package Query -->
<queries>
    <package android:name="com.google.android.apps.healthdata" />
    <intent>
        <action android:name="androidx.health.ACTION_SHOW_PERMISSIONS_RATIONALE" />
    </intent>
</queries>

<application>
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="androidx.health.ACTION_SHOW_PERMISSIONS_RATIONALE" />
        </intent-filter>
    </activity>

    <!-- Required: Privacy Policy Activity Alias -->
    <activity-alias
        android:name="ViewPermissionUsageActivity"
        android:exported="true"
        android:targetActivity=".MainActivity"
        android:permission="android.permission.START_VIEW_PERMISSION_USAGE">
        <intent-filter>
            <action android:name="android.intent.action.VIEW_PERMISSION_USAGE" />
            <category android:name="android.intent.category.HEALTH_PERMISSIONS" />
        </intent-filter>
    </activity-alias>
</application>

Note: MainActivity must extend FlutterFragmentActivity (not FlutterActivity) for Android 14+.

iOS

Add to ios/Runner/Info.plist:

<key>NSHealthShareUsageDescription</key>
<string>This app needs access to your health data to provide insights.</string>

<key>NSHealthUpdateUsageDescription</key>
<string>This app needs permission to update your health data.</string>

⚠️ Platform Limitations

🔒 Privacy & Security

• ✅ Consent-first design
• ✅ AES-256-CBC encryption
• ✅ Automatic key management
• ✅ Anonymized UUIDs
• ✅ Right to forget (revoke & delete)

📖 Additional Resources

• Full API Documentation — Complete API reference
• GitHub Issues — Report bugs or request features
• pub.dev Package — Package details

📋 Detailed Sections

Set<PermissionType> permissions;
if (Platform.isAndroid) {
  permissions = {
    PermissionType.heartRate,
    PermissionType.heartRateVariability, // RMSSD on Android
    PermissionType.steps,
    PermissionType.calories,
    // Distance supported via DISTANCE_DELTA
  };
} else {
  permissions = {
    PermissionType.heartRate,
    PermissionType.heartRateVariability,
    PermissionType.steps,
    PermissionType.calories,
    PermissionType.distance,
  };
}

final result = await synheart.requestPermissions(
  permissions: permissions,
  reason: 'This app needs access to your health data.',
);

import 'dart:async';
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:synheart_wear/synheart_wear.dart';

class HealthMonitor extends StatefulWidget {
  @override
  _HealthMonitorState createState() => _HealthMonitorState();
}

class _HealthMonitorState extends State<HealthMonitor> {
  late SynheartWear _sdk;
  StreamSubscription<WearMetrics>? _hrSubscription;
  WearMetrics? _latestMetrics;
  bool _isConnected = false;

  @override
  void initState() {
    super.initState();
    _sdk = SynheartWear(
      config: SynheartWearConfig.withAdapters({DeviceAdapter.appleHealthKit}),
    );
  }

  Future<void> _connect() async {
    try {
      final result = await _sdk.requestPermissions(
        permissions: {
          PermissionType.heartRate,
          PermissionType.steps,
          PermissionType.calories,
        },
        reason: 'This app needs access to your health data.',
      );

      if (result.values.any((s) => s == ConsentStatus.granted)) {
        await _sdk.initialize();
        final metrics = await _sdk.readMetrics();
        setState(() {
          _isConnected = true;
          _latestMetrics = metrics;
        });
      }
    } catch (e) {
      print('Error: $e');
    }
  }

  void _startStreaming() {
    _hrSubscription = _sdk.streamHR(interval: Duration(seconds: 3))
      .listen((metrics) {
        setState(() => _latestMetrics = metrics);
      });
  }

  @override
  void dispose() {
    _hrSubscription?.cancel();
    _sdk.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Health Monitor')),
      body: _isConnected
          ? Column(
              children: [
                if (_latestMetrics != null) ...[
                  Text('HR: ${_latestMetrics!.getMetric(MetricType.hr)} bpm'),
                  Text('Steps: ${_latestMetrics!.getMetric(MetricType.steps)}'),
                ],
                ElevatedButton(
                  onPressed: _startStreaming,
                  child: Text('Start Streaming'),
                ),
              ],
            )
          : Center(
              child: ElevatedButton(
                onPressed: _connect,
                child: Text('Connect to Health'),
              ),
            ),
    );
  }
}

try {
  final metrics = await synheart.readMetrics();
  if (metrics.hasValidData) {
    print('Data available');
  }
} on PermissionDeniedError catch (e) {
  print('Permission denied: $e');
} on DeviceUnavailableError catch (e) {
  print('Device unavailable: $e');
} on SynheartWearError catch (e) {
  print('SDK error: $e');
}

┌─────────────────────────┐
│   synheart_wear SDK     │
├─────────────────────────┤
│ Device Adapters Layer   │
│ (Apple, Fitbit, etc.)   │
├─────────────────────────┤
│ Normalization Engine    │
│ (standard output schema)│
├─────────────────────────┤
│   Local Cache & Storage │
│   (encrypted, offline)  │
└─────────────────────────┘

🤝 Contributing

We welcome contributions! Please see our Contributing Guidelines or:

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

👥 Authors

• Israel Goytom - Initial work - @isrugeek
• Synheart AI Team - RFC Design & Architecture

Made with ❤️ by the Synheart AI Team

Technology with a heartbeat.