Toggle and Roll

The wrist watch made the pocket watch obsolete. Might the same occur
with palmtops, blackberries and cell phones? It would require more
real estate on the wrist for the display, and dramatically more if the
entry system were conventional.
The finger tip can be used for two unique, distinguishable functions
without moving the point of contact. Force applied to the points of
the compass, toggling, and rolling the finger. Imagine an inked finger
on a stamp. The position of the stamp can be moved, an analog of
toggling, and the area of the fingerprint expanded, the point of force
can be 'rolled'.
A raised toggle or 'tump' inside a circle of pressure sensitive points
would allow the entry of lowercase alphabetical characters, numbers and
functions in an area no more than a couple of square centimeters.
Using such an entry device might take some time to learn, but it might
be just what the technophile ordered, or didn't know he needed, as the
case may be.