Wrong characters when using HID interface

Using Arduino Interfacing w/ Software on the Computer
1

Hi, I'm using the new Arduino R4 WiFi, I've been experimenting with the hid library(Keyboard) and I've noticed that some characters aren't correct.
As example if i use this program

#include <Keyboard.h>

void setup() {
  Keyboard.begin();
}

void loop() {
  Keyboard.press('+');
  Keyboard.releaseAll();
  delay(1000);
}

Instead of typing '+', Arduino types '^'. Does anyone knows why I'm not getting the correct character?

2

are you using a US layout keyboard on your computer ?

1 Like
3

No, I'm using an Italian keyboard

4

use/send/write key codes instead of symbols

Keyboard.write(KEY_KPPLUS );

you may try:
Keyboard.write('+');
Keyboard.print('+');

Secret HID Scancodes

hidden

5

so that's the issue. The library sends codes that map to an US QWERTY keyboard.

you could double check this doc and

1 Like
6

Ok, now it works. I had to open the Keyboard.cpp file and replacing the array content with the italian version and defining the ALT_GR key as 0xc0.
Thank you for your help

7

great - have fun

1 Like