barcode scanner seminar report
TRANSCRIPT
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ASSIGNMENT ON WIRELESS BARCODE SCANNER
Visvesvaraya Technological University, Belgaum
K.L.E Societys
B. V. Bhoomaraddi College of Engineering & Technology
Hubli-580031
Department of Electrical & Electronics Engineering
Project title
ASSIGNMENT
WIRELESS BARCODE SCANNER
Report submitted by
Sindhu Bijjal - 2BV08EE048
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ASSIGNMENT ON WIRELESS BARCODE SCANNER
WHAT IS A BARCODE SCANNER?
A barcode scanner (which may also be referred to as a barcode reader) is a piece of electronic
equipment that can read printed barcodes. Barcodes are used to manage and track a wide variety of
items, ranging from grocery store items to cars to insects such as bees. A barcode scanner uses a lens,
light source and photo conductor to translate optical impulses to electrical impulses.
BASIC KINDS OF BARCODE SCANNERS
There are many kinds of barcode scanners based on different technologies. Few examples are -
1) PEN-SCANNER- pen wand is the simplest barcode reader. however, because it has to remain in
direct contact with the bar code, must be held at a certain angle, and has to be moved over the
bar code at a certain speed.
2) A SLOT SCANNER- remains stationary and the item with the bar code on it is pulled by hand
through the slot. Slot scanners are typically used to scan bar codes on identification cards. 3) A CCD SCANNER
4) AN IMAGE SCANNER: also called a camera reader, uses a small video camera to capture animage of the bar code and then uses sophisticated digital image processing techniques to decode
the bar code
5) A LASER SCANNER: either hand-held or stationary an easily read a bar code up to 24 inchesaway. To reduce the possibility of errors, a laser scanning may perform up to 500 scans per
second.
6) BLUETOOTH-SCANNER: it uses bluerooth technology to sacn the data. But Bluetooth has a
lesser range than the other wireless technologies.
The barcode scanners can be either-
Attached to computer with a wire
Can be wireless
WIRELESS BARCODE SCANNER
Wireless barcode scanner also known as RF scanner or cordless
scanner operates on wireless frequencies like a cordless
phone. Wireless scanner transmits scanned data to a base
station which is connected to a processor. Wireless barcode
scanners models vary by transmission distance and battery life.
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ASSIGNMENT ON WIRELESS BARCODE SCANNER
UNDERSTANDING BARCODING TECHNOLOGY
WHAT ARE BARCODES?
A barcode is an optical machine-readable representation of data, which shows data about the object to
which it attaches. originally barcodes represented data by varying the widths and spacings of parallel
lines. The barcodes can be represented data by varying the widths and spacings of parallel lines (1D) or
into rectangles, dots, hexagons and other geometric patterns (2D).
Fig 2: samples of 1D and 2D barcodes
http://en.wikipedia.org/wiki/Machine-readable_mediumhttp://en.wikipedia.org/wiki/Rectanglehttp://en.wikipedia.org/wiki/Dothttp://en.wikipedia.org/wiki/Hexagonhttp://en.wikipedia.org/wiki/Hexagonhttp://en.wikipedia.org/wiki/Dothttp://en.wikipedia.org/wiki/Rectanglehttp://en.wikipedia.org/wiki/Machine-readable_medium -
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ASSIGNMENT ON WIRELESS BARCODE SCANNER
RETRIEVE INFORMATION FROM BARCODES
There are many types of commercial barcode standardS. HERE Code 3 of 9, or Code 39 is been
explained indetail
1) Each Code 39 character consists of 5 black stripes sandwiching 4 white spaces.
2) Black stripes, as well as white spaces can be both thin and thick.
3) Code 39s encoding scheme is therefore binary, with thick stripes/spaces representing 1s and
thin stripes/spaces representing 0s (shades of the stripes/spaces do not matter since black and
white simply allows us to differentiate the thickness of stripes/spaces).
4) The following table shows all the available encodings in Code 39.
Fig 2: the representations of the codes of barcode coded as given by39.
For example, the English alphabet, K would correspond to the binary code of length 9: 100000011
(scanning from left to right according to thickness).
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ASSIGNMENT ON WIRELESS BARCODE SCANNER
HARDWARE BLOCK DIAGRAM OF A WIRELESS BARCODE SCANNER
fig 3: block diagram of a complete wireless barcode scanner
Sensor:
Sensor is something which acts as Connectionbetween external world and
internal complex digital circuitry. The scanner reads data by illuminating a section of the bar
code. This is usually done by laser light. light with the photodetector, which is an analog
signal. This analog signal can then be amplified and conditioned, and optionally converted
to digital format using an ADC before being passed to the decoder.
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ASSIGNMENT ON WIRELESS BARCODE SCANNER
Micro-computer:
This is important part of barcode scanner which may contain a Digital Signal
Processor (DSP) or normal Processor. The main function of this micro-computer is to
understand and interpret what actually sensor read. It is programmable, usually by scanning
bar coded programming commands into the system from a special programming menu
included in the system
Battery and Charging Unit:
This is essential only is barcode reader is a cordless device. It mainly consists of a
charging unit and a lithium ion/lithium polymer battery. In case of above example (that is
Motorola scanner) 5V, 620mA battery is used. More importantly battery should be light,
powerful and should have higher life cycles.
Flash Memory
Read/Writeable RAM (a.k.a. Non-Volatile RAM)
This is a type of Random Access Memory chip that does not lose its contents when its power is
turned off; however, it can be intentionally written to, read from, and intentionally erased. It
is a type of RAM and, hence, interacts with the computer or processor as described under
RAM except that it does not lose its contents when power is removed.
Fig 4: wireless barcoder reader application in i-phone