A virtual keyboard allows users to enter text on a touchscreen or with other input devices without a physical keyboard. It works by using a light source like a laser to project an image of a keyboard onto a surface. Sensors detect finger position and key presses, which are sent to processing software to register key inputs. Virtual keyboards offer portability over physical keyboards but have less battery life and depend on surface quality. They may use different projection technologies in the future to overcome current limitations.

2. Contents:
Introduction
Definition
Virtual Keyboard Features
Virtual keyboard Technology
Working Mechanism
Advantages
Disadvantages
Conclusion
References

3. Introduction:
 The aim of this technology
is to develop an
“Augmented Reality”
solution for a handheld
device that enables the
user to write text.
 The first virtual keyboard
was invented by IBM in
1992

4. Definition:
 A virtual keyboard is a
software component that allows
a user to enter characters.
A virtual keyboard can usually
be operated with multiple input
devices, which may include a
touch screen, an actual
computer keyboard .
 Virtual keyboard is also called
as projection keyboard.
Virtual keyboard
with screen

5. Virtual keyboard
Features:
 Most of the projection keyboards
use a red diode laser as a light
source.
 Virtual keyboard size is usually
295mm*95mm.
 Virtual keyboard can be connected
by using either by USB ports or
Bluetooth.
 Virtual keyboard works on lithium
ion batteries.
 Virtual keyboard capacity is 120
minutes of continuous typing.

6. Virtual keyboard technology:
 This system comprises three modules :-
i. The sensor module
ii. IR light source
iii. The patter projector

7. i. Sensor Module :Operates by locating the users fingers
in 3 –D space and tracking the intended keystrokes.
ii. IR Light Source :It emits a beam of infrared light helps
in recognizing hand movements and the pressing of the
keys.

8. iii. Pattern Projector :Image can be projected on flat
surface. The projected image is that of standard
QWERTY keyboard, with all the keys and control
functions as in keyboard. The pattern projector or
optional printer image presents the image of the
keyboard by the system.

9. Working Mechanism:
The keyboard pattern projection displays a virtual
keyboard pattern on a flat surface as a desktop surface.
When user touches the key the top of finger will be
illuminated by the lighting plane created by linear laser.

10.  Infrared light cam captures the images of the illuminated
fingers and send the image to the signal processing
software .The position of illuminated finger is detected and
localized by the software , and it will be related key input
events.

11. Advantages:
 Portability.
 Speed of text accuracy.
 Alternative keyboard
layouts.
 Flexibility.
 Lack of need flat or large
typing space.

12. Disadvantages:
 Poor video output quality
is less than expected.
 Unusable virtual keyboard
in portrait mode.
 Relatively poor battery life.
 The keyboard utility
depends on the surface on
which it is located.
 virtual keyboard is very
costly ranging from 150 to
200 dollars

13. Conclusion:
 Projection key boards or virtual key boards claim to provide
the convenience of compactness with the advantages of a
full-blown QWERTY keyboard.
 A virtual keyboard based on 3-D optical range camera.
 Virtual Keyboard is also used in 6th sense technology
device in which it is not depends on surface. the feedback
text and/or graphics may be integrated with such projector,
thus enabling truly virtual working area.
 Thus virtual keyboards will make typing easier, faster, and
almost a pleasure.

14.  http://en.wikipedia.org/wiki/Virtual_keyboard
 http://www.dfrobot.com/wiki/index.php/Laser_Keyboard_
Kit_(SKU:KIT0030)
 http://www.ehow.com/list_5772511_advantages-virtual-
laser-keyboard.html
 http://en.wikipedia.org/wiki/Projection_keyboard#Interpr
etation_and_communication_.28Sensor_module.29
 http://en.wikipedia.org/wiki/Projection_keyboard
 https://www.google.co.in/search?q=virtual+keyboard+ima
ges&biw=800&bih=509&tbm=isch&tbo=u&source=univ&sa
=X&ei=PhsuVIugOY-hugSxpoGQBA&ved=0CBsQsAQ
References: