protected Boolean doInBackground(Void... params) {
    while (true) {
        camera.takePicture(null, null, new PictureCallback() {
            @Override
            public void onPictureTaken(byte[] data, Camera camera) {
                try {
                    file = new File(dir, "test.jpg");
                    outputStream = new FileOutputStream(file);
                    outputStream.write(data);
                    outputStream.close();
                    publishProgress();
                } catch (IOException e1) {}
            }
        });

        try {
            Thread.sleep(300000);
        } catch (InterruptedException e) {}
    }
}