vitallens_flutter

A Flutter plugin wrapping the Rouast VitalLens SDK for contactless facial vital sign estimation (Heart Rate, HRV, Respiration, and real-time rPPG pulse waveforms) using ordinary camera video.

pub points License: MIT

Features

  • πŸ«€ Heart Rate (HR): High-accuracy resting pulse estimation in Beats Per Minute (BPM).
  • πŸ“ˆ Heart Rate Variability (HRV): Autonomic stress & resilience metrics (SDNN and RMSSD in ms).
  • 🫁 Respiration Rate (RR): Breathing frequency in Breaths Per Minute (BrPM).
  • πŸ“Š Real-time Waveforms: Raw photoplethysmogram (rPPG) and respiratory time-series signals.
  • 🎯 Turnkey Guided UI: Pre-built 30-second scanning screen with face mesh alignment guidance.
  • ⚑ Continuous Live Monitor: Real-time physiological waveform streaming.
  • πŸ›‘οΈ Android 15+ 16 KB Compatible: Zero crashes on modern 16 KB page-size kernels.

Installation

Add vitallens_flutter to your pubspec.yaml:

flutter pub add vitallens_flutter

Platform Setup

Android

  1. In your android/app/build.gradle (or build.gradle.kts), set minSdkVersion to at least 26:
android {
    defaultConfig {
        minSdk = 26
    }
}
  1. Ensure your android/app/src/main/AndroidManifest.xml includes camera permissions:
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.INTERNET" />

Usage

1. 30-Second Guided Vital Scan

Obtain an API key from Rouast Labs. Pass it dynamically when starting a scan:

import 'package:flutter/material.dart';
import 'package:vitallens_flutter/vitallens_flutter.dart';

Future<void> runFaceScan(BuildContext context) async {
  // Pass your VitalLens API key dynamically
  final VitalLensResult result = await VitalLens.startScan(
    apiKey: const String.fromEnvironment('ROUAST_API_KEY'),
    method: 'vitallens',
    mode: VitalLensMode.eco, // 15 FPS (or VitalLensMode.standard for 30 FPS)
  );

  if (result.isCompleted && !result.isCancelled) {
    print('Heart Rate: ${result.heartRate?.toStringAsFixed(1)} BPM');
    print('HRV (SDNN): ${result.hrvSdnn?.toStringAsFixed(1)} ms');
    print('Respiration: ${result.respiratoryRate?.toStringAsFixed(1)} BrPM');
    print('Confidence: ${(result.faceConfidence! * 100).toInt()}%');
  } else if (result.isCancelled) {
    print('Scan cancelled by user');
  } else {
    print('Scan error: ${result.message}');
  }
}

2. Rendering Real-Time rPPG Waveforms

The package includes a ready-to-use PpgWaveformView widget for rendering raw pulse signals:

import 'package:flutter/material.dart';
import 'package:vitallens_flutter/vitallens_flutter.dart';

Widget buildPulseWave(List<double> ppgSamples) {
  return SizedBox(
    height: 120,
    child: PpgWaveformView(
      dataPoints: ppgSamples,
      strokeColor: Colors.cyanAccent,
      strokeWidth: 2.5,
      showGrid: true,
    ),
  );
}

3. Continuous Live Monitor

To launch continuous real-time waveform monitoring:

await VitalLens.startMonitor(
  apiKey: myApiKey,
  mode: VitalLensMode.standard,
);

Security Best Practice

Important

Never hardcode production API keys in your public source repository. Use --dart-define or flutter_dotenv to supply keys at build/run time:

flutter run --dart-define=ROUAST_API_KEY=your_key_here

License

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

Libraries

vitallens_flutter