Fig. 1 shows the display of the smart phone vibration watch
application. When a user flicks toward the left on the smart
phone display, the phone vibrates one short vibration and one
long vibration corresponding to the hour ‘15’ (i.e., ‘+ ++ ’).
At the same time, the display on the smart phone indicates
the time 15:10 in white characters on black background for
low vision. The user can increase (decrease) the basic unit
length by tapping the lower left (right) of the screen. The basic
unit length is displayed in the center of the lower part of the
screen. The user can also hear the time with a voice by tapping
the center of the upper right of the screen. If the upper right
area of the screen is tapped, the smart phone sounds a railway
noise. This function is for demonstration. A participant of the
demonstration can feel the time by vibration even though he
or she cannot hear the voice for time. The application program
used in the experiment described below has a function of
setting the time instead of sounding a noise.