12-03-2011, 11:52 AM
vk final11.rtf (Size: 5.3 MB / Downloads: 134)
1. INTRODUCTION
Virtual Keyboard
is just another example of today’s computer trend of
‘smaller and faster’. Computing is now not limited to desktops and laptops, it has
found its way into mobile devices like palm tops and even cell phones. But what has
not changed for the last 50 or so odd years is the input device, the good old QWERTY
keyboard. The virtual keyboard technology is the latest development.
The virtual keyboard technology uses sensor technology and artificial
intelligence to let users work on any flat surface as if it were a keyboard. Virtual
Keyboards lets you easily create multilingual text content on almost any existing
platform and output it directly to PDAs or even web pages. Virtual Keyboard, being a
small, handy, well-designed and easy to use application, turns into a perfect solution
for cross platform text input.
The main features are: platform-independent multilingual support for
keyboard text input, built-in language layouts and settings, copy/paste etc. operations
support just as in a regular text editor, no change in already existing system language
settings, easy and user-friendly interface and design, and small file size.
The report first gives an overview of the QWERTY keyboards and the
difficulties arising from using them. It then gives a description about the virtual
keyboard technology and the various types of virtual keyboards in use. Finally the
advantages, drawbacks and the applications are discussed.
2. QWERTY KEYBOARDS
1.1 Introduction
QWERTY is the most common keyboard layout on English-language computer and
typewriter keyboards. It takes its name from the first six characters seen in the far left of
the keyboard's top first row of letters.
2.2 Working
The working of a typical QWERTY keyboard is as follows:
1. When a key is pressed, it pushes down on a rubber dome sitting beneath the key.
A conductive contact on the underside of the dome touches (and hence connects)
a pair of conductive lines on the circuit below.
2. This bridges the gap between them and allows electric current to flow (the open
circuit is closed).
3. A scanning signal is emitted by the chip along the pairs of lines to all the keys.
When the signal in one pair becomes different, the chip generates a "make code"
corresponding to the key connected to that pair of lines.
4. The code generated is sent to the computer either via a keyboard cable (using on-
off electrical pulses to represent bits) or over a wireless connection. It may be
repeated.
5. A chip inside the computer receives the signal bits and decodes them into the
appropriate keypress. The computer then decides what to do on the basis of the
key pressed (e.g. display a character on the screen, or perform some action).