This presentation is about 2 Computer Hardware components: Light Pen and Barcode Reader.

1. Light pen
Barcode reader
by Paakhi, Prarthna, Neha, Kannagi, Juveria – IX D

2.  A barcode reader (or
barcode scanner) is an
electronic device for
reading printed
barcodes.
 Like a flatbed scanner,
it consists of a light
source, a lens and a
light sensor translating
optical impulses into
electrical ones.
 Additionally, nearly all barcode readers
contain decoder circuitry analyzing the
barcode's image data provided by the sensor
and sending the barcode's content to the
scanner's output port.

3. What is a Barcode?
A barcode is a pattern of
printed bars on various types of
products.
How does the Barcode
Reader work?
A light-sensitive detector in the
barcode reader that identifies
the bar code image by
recognizing special bars at the
both ends of the image.

4. Barcode readers can be differentiated by
technologies as follows: ________________________________________________________________
_______
Pen type readers
Laser scanners
CCD readers
Camera based readers
Omni-directional barcode
scanners
Pen scanners
PDA scanners
_____________________________________________________________
_______

5. A light pen is a computer input device in the
form of a light-sensitive wand used in
conjunction with a computer’s CRT display.
It allows the user to point to displayed
objects or draw on the screen in a similar way
to a touch screen but with a greater positional
accuracy . It was long though that a light pen
can work with any
It was long though that a light pen can work
with any CRT-based display , but not with
LCDs and other display technologies .
However, in 2011 fairlight instruments
released its fairlight CMI-30A , which uses
17’’ LCD monitor with light pen control .

6. What is a light-pen?
A handheld pen-like
photosensitive device held to
the display screen of a
computer terminal for passing
information to the computer.
How does the light-pen
work?
A light pen detects a change of
brightness of nearby screen
pixels when scanned by cathode
ray tube election beam and
communicates the timing of the
event of the computer.