This document discusses virtual keyboards as an alternative input method for small devices. A virtual keyboard uses a laser projection system to project the image of a keyboard onto any flat surface. It allows users to type by touching the projected keys, which are detected by an infrared sensor. The document describes the components of a virtual keyboard system including infrared sensors, lasers, and projectors. Advantages include portability and flexibility, while disadvantages include poor battery life and dependence on surface type. Virtual keyboards aim to provide full keyboard typing on small devices.

1. VIRTUAL KEYBOARD
C.SRI SUDHEERA (13891A0414)
DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING
VIGNANINSTITUTE OF TECHNOLOGYAND SCIENCE
csrisudheera@gmail.com
ABSTRACT
Input to small devices is becoming an
increasingly crucial factor in development
for the ever-more powerful embedded
market. Speech input promises to become
a feasible alternative to tiny keypads, yet
its limited reliability, robustness, and
flexibility render it unsuitable for certain
tasks and/or environments. This paper
surveys technology for alphanumeric input
devices using virtual keyboard projection
with a strong focus on touch-typing.
KEYWORDS: sensors, QWERTY keyboard,
pattern projector .
Virtual keyboard
Introduction: Virtual keyboardisjustanother
example of today’scomputertrendof ‘smaller
and faster’.Computingisnownotlimitedto
desktopsandlaptops,ithasfoundwayinto
mobile devicealso.Butwhatisnot changedis
the inputdevice,the good oldQWERTY
keyboard.The virtual keyboardtechnologyisa
tabletopunitthatprojectsa laserimage of a
keyboardonany flatsurface.Theyare not the
electronicdevicetheyare justthe setof lights
that looklikesthe keyboardandworkslike a
keyboard.Inthistechnique we use adevice that
producesthe LASER lightonthe flatsurface.
ThisLASER lightproducedisthe keyboard.It
createsdetectable surface onwhichuserdon’t
needtopressthe keylike normal keyboard,
whena usertouchesthe surface coveredbyan
image of a key,the device recordsthe
correspondingkeystroke. The aimof this
technology istodevelopan“Augmented
Reality”solutionforahandhelddevice that
enablesthe usertowrite text. The firstvirtual
keyboardwasinventedbyIBMin1992. People
withbiggerfingersmayfindthe keyboardson
smart phonesandPDAstoo small.Tomake up
for this,some manufactureshave developed
special virtual laserkeyboardsto accompany
handhelddevices.Insteadof havingtopoke
lightlyaroundyourphone'skeyboard,avirtual
laserkeyboardconnectstothe phone and
projectsa full-sizedvirtual keyboardontoany
flatsurface.
Definition: A virtual keyboard isa software
componentthatallowsauser toenter
characters.A virtual keyboard can usuallybe
operatedwithmultiple inputdevices,which
may include atouch screen,an actual
computerkeyboard anda computermouse.
Virtual keyboardis alsocalledasprojection
keyboard. The laserkeyboard projection isa
sort of an image of real keyboardbutwhich
doesnotreallyexistphysically.

2. Virtual keyboard features:Most of the
projectionkeyboardsuse areddiodeslaserasa
lightsource andmay projecta full size QWERTY
layoutkeyboard.The projectionkeyboardsizeis
usually295mm*95mm andit isprojectedata
distance 60mm fromthe virtual keyboardunit.
The projectionkeyboardmaydetectupto400
characters perminute andit maybe connected
by usingeitherby USB portsor Bluetooth.And
it worksonlithiumionbatteriesandithasa
capacityof at least120 minutesof continuous
typing.Projectionunitsizevariesnotbigger
than 35mm*92mm*25mm.
Virtual keyboard technology: Thissystem
comprisesthree modules :-
1. The sensormodule
2 .IR lightsource
3. The patterprojector
1. Sensor Module: Operates by locating user
fingers in 3 –D space and tracking the
intended keystrokes.
2. IR Light Source: It emits a beam of infrared
lighthelpsinrecognizing hand movements and
pressing of the keys.
3. PatternProjector: Image can be projectedon
flat surface. The projected image is that of
standard QWERTY keyboard,withall the keys
and control functions as in keyboard. The
pattern projector or optional printer image
presents the image of the keyboard by the
system.
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.

3. 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.
Advantages:
a. Portability.
b. Speed of text accuracy.
c. Alternative keyboard layouts.
d. Flexibility.
e. Lack of need flat or large typing space.
Disadvantages:
a. Poor video output quality is less than
expected.
b. Unusable virtual keyboard in portrait mode.
c. Relatively poor battery life.
d. The keyboard utility depends on the surface
on which it is located.
e. It is very costly ranging from 150 to 200
dollars.
Conclusion:Projectionkeyboardsorvirtual
keyboardsclaimto provide the convenience of
compactnesswiththe advantagesof a full-
blownQWERTY keyboard.A virtual keyboard
basedon 3-D optical range camera. Virtual
Keyboardisalsousedin6th
sense technology
device inwhichitisnot dependsonsurface.the
feedbacktextand/orgraphicsmaybe
integratedwithsuchprojector,thusenabling
trulyvirtual workingarea. Thusvirtual
keyboardswill make typingeasier,faster,and
almosta pleasure.
References:
http://en.wikipedia.org/wiki/Virtual_keyboar
d
http://www.dfrobot.com/wiki/index.php/
Laser_Keyboard_Kit_(SKU:KIT0030)
http://www.ehow.com/list_5772511_adva
ntages-virtual-laser-keyboard.html
http://en.wikipedia.org/wiki/Projection_k
eyboard#Interpretation_and_communicati
on_.28Sensor_module.29
http://en.wikipedia.org/wiki/Projection_k
eyboard
https://www.google.co.in/search?q=virtua
l+keyboard+images&biw=800&bih=509&tb
m=isch&tbo=u&source=univ&sa=X&ei=Phs
uVIugOY-hugSxpoGQBA&ved=0CBsQsAQ