USB-keyboard/HID-interface using VUSB and ATmega328 based Arduino courtesy of
work in progress » V-USB tutorial (software-only usb for mega & tiny)
USB HID keyboard with V-USB | Code and Life
HID-class USB Serial Communication for AVRs using V-USB « RAYSHOBBY.NET
AZDelivery Scheda AZ-Atmega328-Board con Atmega328 CH340 Chip versione saldata con Cavo USB, compatibile Con AZ-Atmega328-Board con eBook : Amazon.it: Informatica