Keyboard.h is not included in the project. ``` #if defined(FEATURE_CW_COMPUTER_KEYBOARD) #include <Keyboard.h> #endif //defined(FEATURE_CW_COMPUTER_KEYBOARD) ``` [link](https://github.com/k3ng/k3ng_cw_keyer/blob/master/k3ng_keyer/k3ng_keyer.ino#L799) Maybe i missed some instructions but I can't find the file anywhere. 73 and thank you for this great piece of software :)