A device for converting a scanning electron microscope to a scanning transmission electron microscope is adapted to be mounted on a conventional SEM. A failure of a shareable unit in one processor causes that processor to share the corresponding unit in another processor on the same chip. The system further includes an impairment profile generator, an information database including audiovisual information to be displayed to the person according to the impairment profile, and an audiovisual display unit. Therefore, they can be forged with simple dies, or may be manufactured by other methods such as machining.