addition to visual and auditory displays, there are displays that
utilize other human senses, principally touch and smell. Although
these senses are less frequently used for display purposes, there
are times when the presentation of information in these sense modalities
is essential due to conditions that hamper or preclude vision or
adverse conditions can range from sensory overload to environments
that are too dark, too bright, or too obstructed for vision or too
noisy for hearing. This section introduces the next most widely
used non-visual/non-auditory display types, that is, tactual (somatosensory)
and smell (olfactory).
braking systems (ABS) provide tactual/ haptic feedback to the
driver when they are engaged. The brake pedal pulsates, indicating
the anti-lock brakes are activated.
computer control rooms and maintenance areas are equipped
with carbon dioxide, CO2, fire suppression systems.
CO2 is a colorless, odorless gas that is hazardous
to humans in closed environments. Therefore, some systems
add the scent of wintergreen to the CO2 to signal