Tactile screens and mobility

The PDA has a long history with touch screens. Their functions to allow you to easily organize the device quickly lead to additional functions, making the use of fixed buttons complex, with the different actions being activated from the same buttons, often to the detriment of the ergonomics.

If a non tactile screen and reduced number of buttons are all that is needed for mobile phones, inputting data into a device like a PDA requires that we find other interaction methods between man and machine.



A function of touch screens is particularly attractive for this kind of applications: the possibility of inputting text manually, with or without writing recognition. For economical reasons, the choice of touch screen technology is based on screens that can manage only a single point of contact at a time.

To accelerate the input and resolve of problem of characters that require numerous writing traits, codes were invented, which worked well enough. They lead to the success of the Graffiti and Graffiti 2 systems on Palm OS, which was then quickly picked up by the PocketPC 2000 system which was followed by Windows Mobile.

But inputting characters isnt the only use of the touch screen. It allows you to redefine the virtual control buttons depending on the application that is launched, with their use being as ergonomical as possible (to try and please users), while keeping the compact format for mobile devices and at the same time allowing for increased functions as technologies become smaller.