No More "Hey Google"! Add your Wake Phrase to an Android app

You cannot change Google hotwords "Hey Google", "OK Google" but you can get your Android app have its own wake phrase with Porcupine Wake Word

Let's get started
Add the Porcupine Wake Word Library

Make sure you have a reference to Maven Central in your project’s build.gradle file:

repositories {
  mavenCentral()
}

Add the following reference to your app’s

build.gradle
file:

dependencies {
  implementation 'ai.picovoice:porcupine-android:${LATEST_VERSION}'
}

Create a Background Service

public class PorcupineService extends Service {

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        return super.onStartCommand(intent, flags, startId);
    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onDestroy() {        
        super.onDestroy();
    }
}

in your MainActivity, add code to start and stop the PorcupineService:

private void startService() {
    Intent serviceIntent = new Intent(this, PorcupineService.class);
    ContextCompat.startForegroundService(this, serviceIntent);
}

private void stopService() {
    Intent serviceIntent = new Intent(this, PorcupineService.class);
    stopService(serviceIntent);
}

Request Audio Permissions
In AndroidManifest.xml, add this:

<uses-permission android:name="android.permission.RECORD_AUDIO"/>

Check if you have permission to record audio in the MainActivity and if not, ask the user for it. Add the following code to achieve this:

private boolean hasRecordPermission() {
    return ActivityCompat.checkSelfPermission(this, Manifest.permission.RECORD_AUDIO) 
        == PackageManager.PERMISSION_GRANTED;
}

private void requestRecordPermission() {
    ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.RECORD_AUDIO}, 0);
}

@Override
public void onRequestPermissionsResult(int requestCode, 
                                       @NonNull String[] permissions, 
                                       @NonNull int[] grantResults) {    
    if (grantResults.length == 0 || 
        grantResults[0] == PackageManager.PERMISSION_DENIED) {
        // handle permission denied
    } else {
        startService();
    }
}

Launch Wake Word Engine from a Service
For this demo, we'll use one of built-in keywords, ‘Computer’. However, you can train a custom wake phrase on the Picovoice Console by signing up for free.

You also need an AccessKey which can be found on your Picovoice Console dashboard.

In our PorcupineService class, we’ll create an instance of PorcupineManagerto handle audio capture and processing. The service class now looks like this:

import ai.picovoice.porcupine.Porcupine;
import ai.picovoice.porcupine.PorcupineException;
import ai.picovoice.porcupine.PorcupineManager;

public class PorcupineService extends Service {
  private String accessKey = "..."; // your Picovoice AccessKey
  private PorcupineManager porcupineManager;  

  @Override
  public int onStartCommand(Intent intent, int flags, int startId) {
    try {
        porcupineManager = new PorcupineManager.Builder()
                .setAccessKey(accessKey)
                .setKeyword(Porcupine.BuiltInKeyword.COMPUTER)
                .setSensitivity(0.7f)
                .build(getApplicationContext(),
                        (keywordIndex) -> {
                          // wake word detected!
                        });
        porcupineManager.start();
    } catch (PorcupineException e) {
        Log.e("PORCUPINE_SERVICE", e.toString());
    }
    return super.onStartCommand(intent, flags, startId);
  }

  @Nullable
  @Override
  public IBinder onBind(Intent intent) {
      return null;
  }

  @Override
  public void onDestroy() {
      try {
          porcupineManager.stop();
          porcupineManager.delete();
      } catch (PorcupineException e) {
          Log.e("PORCUPINE", e.toString());
      }
      super.onDestroy();
  }
}

Voila!

Resources:
The tutorial was originally published on Medium.
Porcupine Android SDK
Tutorial Source Code
Picovoice.ai

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No More "Hey Google"! Add your Wake Phrase to an Android app

Dilek Karasoy

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