My HC 05 module does not receive data

[Ismael_Montero_Rinal]

Hi, I'm using an HC 05 module to make an LED turn on and off. The issue is that the buttons on the apk do not work. I downloaded a Serial Bluetooth Terminal and the module can send data. Here is the code I am using:

void setup()
{
  Serial.begin(38400);
  pinMode(13, OUTPUT);
}

void loop()
{
  if (Serial.available() > 0)
  {
    char data = Serial.read();
    if (data == 'a')
    {
      digitalWrite(13, HIGH);
    }
    else if (data == 'b')
    {
      digitalWrite(13, LOW); 
    }
  }
}

[SteveJG]

This might be helpful

HC 05 Bluetooth Module not connecting to MIT app defined in ROINCO arduino multipurpose kit

I think you are using this example: In Designer - BluetoothClient1 - DelimiterByte: 10 What is your Arduino code? Here examples of Arduino + Bluetooth classic

also this might help https://www.youtube.com/watch?v=w5LgLsCumFI

[Ismael_Montero_Rinal]

Thank you! So I didn't really figure out what was wrong with what I had but I saw that some people set pins 3 and 4 to be their RX and TX and that worked for me.