> An inherent problem with all finger-touch systems is that the > finger, by definition, must obscure the object being touched > (unless one has a giant screen with giant buttons). Apple has > actually come up with a clever way to display the button anyway: As > the user presses down on the "D" key, for example, a bigger image > of the "D" key in a dialog balloon, as in a comic, appears just > above the finger. > > Unfortunately, as far as I can tell, the balloon can only be made > to display once the user had committed to the letter, thus acting > to announce errors, rather than prevent them. > Excellent point, and he follows up with useful suggestions.
> The iPhone needs a two-level touch-sensing system. That would allow > the user to press lightly on the keyboard to cause the dialog > balloons to appear, then press harder as they confirm that the > correct letter is displayed. Such direct feedback would accelerate > the learning curve for the young while giving older people with > large fingers—or arthritic fingers—an alternative to the > frustration of high continuing error rates. > As I've mentioned on this list, looking for a two-plateau area-
coverage profile as the user goes from 'touch' to 'press' should be
easy enough to do. The question would be whether it's possible to
create a generic profile; if not, you'd have to have the touch device
and the user learn each others' styles over time.
> Force Feedback > > Another major win for the iPhone would be force-feedback, so users > could "feel" the key has been pressed. For a long time, lack of > such feedback was something taken for granted with touch screens, > but no longer. It turns out that if you move the entire device up > and down rapidly when the user has achieve sufficient contact, > hammering the device against the finger, the user's brain > interprets that movement as a physical click. It also turns out > that cell phones all already have a device to move the phone around— > the vibrator used as a ringer alternative. > Another vote for haptic feedback. I will take that as vindication.
> Of course, most cellphone vibrators move the phone in two > dimensions, since they consist of motors with offset weights, but > Immersion Corporation's VibeTonz technology replaces the rotary > vibrator with one that goes strictly up and down. When that > vibrator is triggered by a completed virtual keypress, the user is > given just enough of a nudge to indicate to the brain that the > keypress was successful. > See also the research on modeling the haptic illusion of different
shapes and types of surfaces using different vibration profiles.