Galaxy S20 to Arduino Nano

[tesorrells]

I am trying to send some serial data from my android app to an arduino nano, just some numbers, and when i hit the button to send the nano RX light flashes, but the code on the nano doesn't do anything, as it should, with the data. I'm using a USB-C to USB-C cable, as when i tried to usb an OTG cable it did not recognize the USB device was even there on the android side. Not sure if the issue is on the android side or the nano side. I tried reading from serial to see if that produced anything and it just crashed.

` protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main);

    cameraButton = findViewById(R.id.cameraButton);
    detectButton = findViewById(R.id.detectButton);
    imageView = findViewById(R.id.imageView);

    // usb connection
    // Find all available drivers from attached devices.
    UsbManager manager = (UsbManager) getSystemService(Context.USB_SERVICE);
    List<UsbSerialDriver> availableDrivers = UsbSerialProber.getDefaultProber().findAllDrivers(manager);
    PendingIntent mPermissionIntent = PendingIntent.getBroadcast(this, 0, new Intent(
            ACTION_USB_PERMISSION), 0);
    IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION);
    registerReceiver(usbReceiver, filter);
    if (availableDrivers.isEmpty()) {
        this.sourceBitmap = Utils.getBitmapFromAsset(MainActivity.this, "muj.jpg");

        this.cropBitmap = Utils.processBitmap(sourceBitmap, TF_OD_API_INPUT_SIZE);

        this.imageView.setImageBitmap(cropBitmap);
        return;
    }

    // Open a connection to the first available driver.
    UsbSerialDriver driver = availableDrivers.get(0);
    UsbDeviceConnection connection = manager.openDevice(driver.getDevice());

    UsbDevice device = driver.getDevice();
    if (connection != null) {
        manager.requestPermission(device, mPermissionIntent);
    }

    UsbSerialPort port = driver.getPorts().get(0); // Most devices have just one port (port 0)
    try {
        port.open(connection);
    } catch (IOException e) {
        e.printStackTrace();
    }
    try {
        port.setParameters(115200, 8, UsbSerialPort.STOPBITS_1, UsbSerialPort.PARITY_NONE);
    } catch (IOException e) {
        e.printStackTrace();
    }

    cameraButton.setOnClickListener(v ->
            startActivity(new Intent(MainActivity.this, DetectorActivity.class)));

    detectButton.setOnClickListener(v -> {

        Handler handler = new Handler();

        new Thread(() -> {
            handler.post(new Runnable() {
                @Override
                public void run() {
                    try {
                        port.write("60".getBytes(), 5);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                    byte response[] = {};
                    try {
                        port.read(response, 5);
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            });
        }).start();

    });

    initBox();
}

`

[kai-morich]

typical issues are wrong baud rate or incomplete permission handling. please try with example app.

[vish897]

typical issues are wrong baud rate or incomplete permission handling. please try with example app.

Hey! I am having the same issue. I am trying to stream the data continuosly. I tried sending a string from android app to Arduino Uno, I can see the Rx led glowing but LED is not blinling as it should according to the program. However I observed that when I am sending the string just once from the app, the LED blinks but it takes some time to do this after the Rx pin blinks. I think this is the reason for the stream of data working. Is there a way I could set frequency of streaming?

Edit I was able to solve this issue. For those facing the same issue, the following worked for me-

1. Create a seperate thread for streaming of data and do not create it using lambda function. I followed this video for creating a runnable and thread with custom method inside runnable to stop the thread.
2. Add Thread.sleep(milliseconds) between each time you send the data. If I'm not wrong WRITE_WAIT_MILLIS in already an input for the write() method here but that doesn't seem to do the job for me hence I made it 5 and added delay using Thread.sleep(). Note- Check the run time for the code you're using on arduino and set the sleep value of thread accordingly. FOr me 1100 msec seems to work.

I think that since arduino serial communication is interrupt based, and the buffer time between arrival of two simultaneous data is very very less than the time taken by arduino to process a piece of data (in my case LED blinking), the arduino receives the data but fails to process it.