Goal is to make a custom game controller to connect to a Raspberry Pi running Retropie. That project is a pre-requisite for a handeld gaming console. That project is on "standby" because I found joystick USB encoder which solves my problem, like http://www.smallcab.net/advanced_search_result.php?x=0&y=0&keywords=usb+encoder / http://www.smallcab.net/encoder-usb-arcade-joystick-buttons-player-28mm-terminals-p-274.html