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 one or more streams;

    class _MyHomePageState extends State<MyHomePage> {
   
  final _controller = SensorBasedNavController3.instance; //Model3/Controller3 is currently the only one that can be used. Please use this one.
  Future<void> initializeAndLoad() async {
    await _controller.initialize();
    await startPrediction();
  }
  
  Future<void> startPrediction() async {
    // Typically, only one of these 3 streams should be required, depending on how the navigation is to be implemented. 
    // This example is only intended to show how they are subscribed to and what data they return
    _controller.coordiates.listen((coordiatesValues) { //Type: LatLng[double Latitude, double Longitude]
      setState(() {
        LatLng currentCoordinates = coordiatesValues; 
      });
    });
    _controller.navData.listen((navDataValues) { // Type navData[double distance, double heading, double height] 
      setState(() {
        NavData currentNavData = navDataValues;
        double distance = currentNavData.distance
        double heading = currentNavData.heading
        double attitude = currentNavData.height
      });
    });
    _controller.meters.listen((metersData) { // Type List<double> double metersToNorth, double metersToEast
      setState(() {
        double northing = metersData[0]
        double easting = metersData[1]
      });
    });
  }
  

Set current coordinates
````dart 
    // Set cooridants as the starting point, for example.
    LatLng newStartCoordinates = LatLng(pos.latitude, pos.longitude);
    double height = 0;
    _controller.setCoordinates(newStartCoordinates, height);

Release mode known Runtime Errors that could occur

• 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'
        }
    }