Press some special characters by HID usage codes

Hi everyone,

I am developing a virtual keyboard device connected to an iOS device by Bluetooth. And how to press any special characters by HID usage. I have tried all combinations of keys option + shift + key or option + key but there aren't any characters that I want

Particularly, I want to press the character '@' in the Lithuanian language for iOS devices by Bluetooth virtual keyboard. Are there any combinations of keys to press these special characters?

Dien Vu

Press some special characters by HID usage codes
 
 
Q