Hello 2018


This article describes how to use the Mnist convolutional neural network to achieve digital recognition through the Sungem-SDK in the Android Studio development environment. The current example uses the camera that comes with the HornedSungem. If you need an external image source, please refer to SungemSDK-AndroidExamples.

step 1: Prepare the development environment

  1. Download the latest versionSungemSDK-Android.jar package
  2. Prerequisites:
    • Make sure minSdkVersion is above Android 3.1
    • Make sure the Android device supports OTG
    • Android Studio 2.0 or higher
  3. Creating a project
  4. Please make sure to read the Android API before using the HornedSungem related functions and services. See API documentation for details.

step 2: Adding the SungemSDK-Android to Your Project

  • Copy the downloaded package to the folder corresponding to your project according to actual needs, for example::

add libs

The lib contains the jar and .so required by horned-sungemSDK and javacv.

Node: Chinese characters cannot be included when adding the libs folder path, otherwise compilation will fail.

  • Open the build.gradle file under the app folder from the Project Files view in Android Studio. Make a note of the path of the libs folder to the right of compile fileTree. This is where you will put the SungemSDK for Android files later on.

set libs

step 3: Adding Device Permissions

Open the AndroidManifest.xml file located under app > src > main and Add the required device permissions to the file.

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.hardware.usb.host"/>
<uses-permission android:name="android.hardware.usb.accessory"/>
<uses-feature android:name="android.hardware.usb.host"/>

step 4: Code description

Here’s a simple hello2018 example to explain how to use the HornedSungem.

  • Download graph_mnist graph file and four test pic,create a new assets package under your module and copy the downloaded files to this directory, as shown in the figure:


  • Init HsDevice, used for HornedSungem communication and display results, as follows:

    mHsDevice = new HsDevice(this) {
        public void openSucceed(UsbDevice usbDevice) {
            Toast.makeText(MainActivity.this, "connection succeeded.", Toast.LENGTH_SHORT).show();
            mUsbDevice = usbDevice;
        public void openFailed() {
            Toast.makeText(MainActivity.this, "Please re-plug and allow permission", Toast.LENGTH_SHORT).show();
        public void disConnected() {
            Toast.makeText(MainActivity.this, "Disconnected", Toast.LENGTH_SHORT).show();
  • Creating the Hello2018Thread class which extends HsThread, the core code is as follows:

    public void run() {
        int status = openDevice();
        if (status != ConnectStatus.HS_OK) {
        int id = allocateGraphByAssets("graph_mnist");
        if (id<0) {
        for (int i = 1; i < 5; i++) {
            int[] ints = new int[28 * 28];
            try {
                InputStream inputStream = mActivity.getAssets().open("hello/" + i + ".jpg");
                Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
                bitmap.getPixels(ints, 0, 28, 0, 0, 28, 28);
            } catch (FileNotFoundException e) {
            } catch (IOException e) {
            float[] float_tensor = new float[28 * 28];
            for (int j = 0; j < 28 * 28; j++) {
                float_tensor[j] = Color.red(ints[j]) * 0.007843f - 1;
            int status_load = loadTensor(float_tensor, float_tensor.length, id);
            if (status_load == ConnectStatus.HS_OK) {
                float[] result = getResult(id);
                if (result != null) {
                    int max = getMaxPossible(result);
    public int getMaxPossible(float[] arr) {
        int max = 0;
        float max_f = 0;
        for (int i = 0; i < arr.length; i++) {
            float temp = arr[i];
            if (temp > max_f) {
                max = i;
                max_f = temp;
        return max;

Operating procedures

  • build your module and run it on an Android device.
  • Enter the launcher Activity.
  • Connect HornedSungem by USB.
  • Waiting for the pop-up permission request.
  • Click OK to open the device.
  • Get calculated results, as the picture shows:


Node: If you do not open the device, the program will perform the openFailed() callback. If you want to use it again, please re-plug the device.

If you want to know more details, please click to view the example tutorial, or download the demo project.