The document describes the components and workings of a barcode scanner. It explains that a barcode scanner shines a light, like an LED or laser, onto the barcode which is then detected by a photoelectric cell. The cell generates a pattern of pulses corresponding to the black and white stripes of the barcode. An ADC converts the analog pulses into binary digits which are sent to a computer to detect the barcode number. Key components are the light source, photoelectric cell, mainboard with ADC and decoder, microcontroller like Arduino, LCD display, and power source like a battery.

1. BARCODE SCANNER
GROUP-II

2. BARCODE
• a machine-readable code in the form of numbers and a pattern of parallel
lines of varying widths, printed on a commodity and used especially for stock
control.

3. WORKING OF BARCODE READER

4. CONTD…
 Scanning head shines LED or laser light onto barcode.
 Light reflects back off barcode into a light-detecting electronic component
called a photoelectric cell. White areas of the barcode reflect most light;
black areas reflect least.
 As the scanner moves past the barcode, the cell generates a pattern of on-off
pulses that correspond to the black and white stripes. So for the code shown
here ("black black black white black white black black"), the cell would be
"off off off on off on off off."
 An electronic circuit attached to the scanner converts these on-off pulses into
binary digits (zeros and ones).
 The binary digits are sent to a computer attached to the scanner, which
detects the code as 11101011

5. COMPONENTS
 LED or laser light
 photoelectric cell
 Mainboard (ADC & Decoder)
 Arduino or microcontroller
 LCD Display
 Battery or power supply
 wire

6. LED
 light-emitting diode (LED) is a semiconductor device that emits light when an
electric current is passed through it.
 Light is produced when the particles that carry the current (known as
electrons and holes) combine together within the semiconductor material.
 Since light is generated within the solid semiconductor material, LEDs are
described as solid-state devices.
 The term solid-state lighting, which also encompasses organic LEDs (OLEDs),
distinguishes this lighting technology from other sources that use heated
filaments (incandescent and tungsten halogen lamps) or gas discharge
(fluorescent lamps).

7. LASER LIGHT
 The letters in the word laser stand for Light Amplification
by Stimulated Emission of Radiation.
 A laser is an unusual light source.
 It is quite different from a light bulb or a flash light.
 Lasers produce a very narrow beam of light.
 This type of light is useful for lots of technologies and instruments—even
some that you might use at home

8. PHOTOELECTRIC CELL
 A photovoltaic (PV) cell is an energy harvesting technology, that
converts solar energy into useful electricity through a process called
the photovoltaic effect.
 There are several different types of PV cells which all use semiconductors to
interact with incoming photons from the Sun in order to generate an
electric current.
 A photovoltaic cell is comprised of many layers of materials, each with a
specific purpose.
 The most important layer of a photovoltaic cell is the specially
treated semiconductor layer.

9. ADC
 An Analog to Digital Converter (ADC) is a very useful feature that converts an
analog voltage on a pin to a digital number.
 By converting from the analog world to the digital world, we can begin to use
electronics to interface to the analog world around us.
 In electronics, an Analog to Digital Converter (ADC) is a device for converting
an analog signal (current, voltage etc.) to a digital code, usually binary.
 In the real world, most of the signals sensed and processed by humans are
analog signals.
 Analog-to-Digital conversion is the primary means by which analog signal are
converted into digital data that can be processed by computers for various
purposes

10. DECODER
 Decoders are digital ICs which are used for decoding.
 In other words the decoders decrypt or obtain the actual data from the
received code, i.e. convert the binary input at its input to a form, which is
reflected at its output.
 It consists of n input lines and 2^n output lines.
 A decoder can be used to obtain the required data from the code or can also
be used for obtaining the parallel data from the serial data received.

11. Arduino
 Arduino is an open-source platform used for building electronics projects.
 Arduino consists of both a physical programmable circuit board (often referred to
as a microcontroller) and a piece of software, or IDE (Integrated Development
Environment) that runs on your computer, used to write and upload computer code
to the physical board.
 The Arduino platform has become quite popular with people just starting out with
electronics, and for good reason.
 Unlike most previous programmable circuit boards, the Arduino does not need a
separate piece of hardware (called a programmer) in order to load new code onto
the board -- you can simply use a USB cable.
 Additionally, the Arduino IDE uses a simplified version of C++, making it easier to
learn to program.
 Finally, Arduino provides a standard form factor that breaks out the functions of
the micro-controller into a more accessible package.

12. LCD Display
 LCD (Liquid Crystal Display) is a type of flat panel display which uses liquid crystals
in its primary form of operation.
 LEDs have a large and varying set of use cases for consumers and businesses, as
they can be commonly found in smartphones, televisions, computer monitors and
instrument panels.
 LCDs were a big leap in terms of the technology they replaced, which include
light-emitting diode (LED) and gas-plasma displays.
 LCDs allowed displays to be much thinner than cathode ray tube (CRT) technology.
 LCDs consume much less power than LED and gas-display displays because they
work on the principle of blocking light rather than emitting it.
 Where an LED emits light, the liquid crystals in an LCD produces an image using a
backlight.

13. Battery
 Lead acid batteries used in the RV and Marine Industries usually consist of two 6-
volt batteries in series, or a single 12-volt battery.
 These batteries are constructed of several single cells connected in series each
cell produces approximately 2.1 volts.
 A six-volt battery has three single cells, which when fully charged produce an
output voltage of 6.3 volts. A twelve-volt battery has six single cells in series
producing a fully charged output voltage of 12.6 volts.
 A battery cell consists of two lead plates a positive plate covered with a paste of
lead dioxide and a negative made of sponge lead, with an insulating material
(separator) in between.
 The plates are enclosed in a plastic battery case and then submersed in an
electrolyte consisting of water and sulfuric acid
 Each cell is capable of storing 2.1 volts.

14. BLOCK DIAGRAM

15. CONNECTION DIAGRAM

16. Cost of components
S.NO NAME COST
1 ARDUINO Rs.465
2 BARCODE SCANNER Rs.1,149
3 LCD DISPLAY Rs.200
4 WIRE Rs.50
5 RESISTOR Rs.5
6 BATTERY(5V) Rs.200
TOTAL Rs.2069

17. THANK YOU!