Make predictions using a .onnx model file directly in the Flutter app.

Key Files #

• onnx_model.dart: Loads model.onnxand provides apredict()` function.
• sensor_based_nav_controller.dart: Collects sensor data and triggers the prediction.

How It Works #

1. HardwareSensorService provides sensor data (accelerometer, gyroscope, magnetometer).

2. SensorBasedNavController:

   • Collects 10 current sensor values (_currentSensorSamples)
   • Stores historical values (_historicalBursts) and past predictions (_historicalDeltas)
   • Prediction Trigger: Once 10 samples are collected, OnnxModel.predict() is called with both current and historical data
     [Code Reference] on GitLab: Sensor-Based-Navigation -> MainBranch
   • After prediction, old data stores are updated
   • Data is updated every 100ms

3. The prediction result is displayed or used within the app.

4. Prerequisite: @ build.gradle

   android {
       compileSdk = flutter.compileSdkVersion
       ndkVersion = "27.0.12077973"
     
       defaultConfig {
           minSdk = 24
           targetSdk = 35
       }
   
   

Usage #

• Subscribe to predictions:

  class _MyHomePageState extends State<MyHomePage> {
  String northing = "0", easting = "0", delta_h = "0"; 
  final _controller = SensorBasedNavController.instance;
  
    @override
    void initState() {
    super.initState();
    initModel();
    startPrediction();
    }
  Future<void> initModel() async {
    _controller.initialize();
      
    }
  
    Future<void> startPrediction() async {
    _controller.predictions.listen((predictedValues) {
      setState(() {
  
        easting = predictedValues[0].toString();
        northing = predictedValues[1].toString();
        delta_h = predictedValues[2].toString();
      });
    });
  }
       
  // UI Output 
  Text('$easting, $northing, $delta_h'),
  

• Add as dependency

    dependencies:
    sensor_based_nav: 1.1.2
  

ONNX Runtime Setup for Release #

• Create or update the file: android/app/proguard-rules.pro and add the following lines:

  -keep class ai.onnxruntime.** { *; }
  -keep class com.microsoft.** { *; }
  

• Update your build.gradle file to include the ProGuard rules:

  configre your build.gradle file to use the proguard rules:
  

    buildTypes {
        release {
            signingConfig = signingConfigs.debug
            minifyEnabled true
            shrinkResources true
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }