Error when trying to send data to Arduino


So for a home security project, I am working on I am gonna be using a phone to be the "Main thingy). And in order to control certain things I need to connect them to an Arduino. In this case an Arduino Uno R3. The problem I am facing now is that I get this error:

int android.hardware.usb.UsbDeviceConnection.bulkTransfer(android.hardware.usb.UsbEndpoint, byte, int, int)

When trying to send data. My code looks like this at the moment. Anyone an idea what causes this? I am using an official Arduino cable with a Samsung OTG usb-c to usb female adapter. Sometimes it will ask to connect to null on my phone.

Thanks for reading :slight_smile:


I connect my arduino via bluetooth but maybe you could try …

It works! TYSM!

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Actually, have another question. Hope you know that too ;). So I cant seem to actually read data from the Arduino. If I do it nothing happens. Never triggers the After Read

Can I see your arduino code ?

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@dora_paz is is what I use atm. I saw it in a tutorial. My thoughts are it should read the println’s

int incomingByte = 0; // for incoming serial data

void setup() {
  Serial.begin(9600); // opens serial port, sets data rate to 9600 bps
  pinMode(13, OUTPUT);

void loop() {
  // send data only when you receive data:
  if (Serial.available() > 0) {
    // read the incoming byte:
    incomingByte =;

    // say what you got:
    Serial.print("I received: ");
    Serial.println(incomingByte, DEC);

    if(incomingByte == 65){

      digitalWrite(13, HIGH);

I actually got it working by using this extension instead of the Arduino one! Thanks for trying to help anyway!


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