Lifi based communication system

LiFi Based Communication System
A Workshop-1 Report
Submitted in partial fulfillment of the requirement for the award of Degree of Bachelor
of Engineering in Electronics & Communication
Submitted to
RAJIV GANDHI PROUDYOGIKI VISHWAVIDHYALAYA
BHOPAL (M.P.)
WORKSHOP-1 REPORT
Submitted By:
Saransh Tiwari (0176EC161070) Shashwat Pratap(0176EC161073)
Shivam Sharma(0176EC161075) Kushagra Pal(0176EC161045)
DEPARTMENT OF ELECTRONICS & COMMUNICARION ENGINEERING
LAKSHMI NARAIN COLLEGE OF TECHNLOGY
EXCELLENCE BHOPAL
Session 2018-19

LAKSHMI NARAIN COLLEGE OF
TECHNOLOGYEXCELLENCE, BHOPAL
Department of Electronics & Communication Engineering
CERTIFICATE
This is to certify that the work embodied in this Workshop-1 title “Lifi
Based Communication System” has been satisfactorily completed by
Saransh Tiwari, Shashwat Pratap, Shivam Sharma and Kushagra Pal,
students of Third year. It is a bonafide piece of work, carried out under my
supervision and guidance in the Department of Electronics &
Communication Engineering, Lakshmi Narain College of Technology
Excellence, Bhopal, for partial fulfillment of the Bachelor of Engineering
during the academic year 2018-19.
Under the Supervision of
_____________________
Project Co-ordinator
Dr. Shivi Chaturvedi
Approved By
____________________
Mukul Shrivastava
Head of the Department

LAKSHMI NARAIN COLLEGE OF TECHNOLOGY
EXCELLENCE, BHOPAL
Department of Electronics & Communication Engineering
DECLARATION
We, Saransh Tiwari, Shashwat Pratap, Shivam Sharma and Kushagra Pal,
students of Bachelor of Engineering, Electronics & Communication
Engineering, Lakshmi Narain College of Technology, Bhopal, here by
declare that the work presented in this Workshop-1 Project is outcome of
our own work, is bonafide, correct to the best of our knowledge and this
work has been carried out taking care of Engineering Ethics. The work
presented does not infringe any patented work and has not been submitted
to any University for the award of any degree or any professional diploma.
____________ _____________
Saransh Tiwari Shashwat Pratap
Enrollment No. 0176EC161070 Enrollment No. 0176EC161073
____________ _____________
Shivam Sharma Kushagra Pal
Enrollment No. 0176EC161075 Enrollment No. 0176EC161045
Date: ___-___-_____
i

ACKNOWLEDGEMENT
Reasons can be given & they can be many but nothing can replace the
efforts of numerous people behind the work, put in by the creator, giving us
constant support all the way. On the very outset I would like to thank
Dr. V. K. Sahu, Principal, LNCTE, Bhopal for providing me the glorious
opportunity to work on this project. I express my hearty gratitude to Dr.
Mukul Shrivastava, Head of Department Electronics & Communication
Engineering. His invaluable guidance, advice & time out of extremely busy
schedule made this work an enthusiastic experience. I wish to express my
most sincere gratitude for her whole hearted cooperation.
I am grateful, beyond my sense of gratitude, to Dr. Shivi
Chaturvedi Project Coordinator, Department of Electronics &
Communication Engineering, for her kind cooperation throughout the
planning & preparation of this project. Working on this project was quite a
wonderful experience & that too an unforgettable one. Without his
unhindered support, sustained interest, unlimited patience, sound counsel &
tremendous knowledge in the field of electronics, this work would have not
been possible.
Nothing can be taken away from my project guide Dr. Shivi
Chaturvedi Department of Electronics & Communication Engineering,
who has been instrumental in guiding us through the various aspects of
designing of our project & implementing the idea of the project “LiFi
Based Communication System”.
ii

TABLE OF CONTENTS
TOPIC NAME PAGE NUMBER
Certificate
Declaration i
Acknowledgement ii
Table of Content iii
Abstract iv
List of Figures v
List of Tables vi
Chapter 1: Introduction 1
Chapter 2: Working of LiFi (3-4)
Chapter 3: Main Components (6-14)
3.1 Arduino Nano 7
3.2 16x2 LCD Display 9
3.3 4x4 Keypad 10
3.4 Photodiode 11
3.5 Transistor 12
3.6 7805CV Voltage Converter 13
3.7 Single Layer PCB 14
Chapter 4: Circuit Diagram (15-17)
4.1 Transmitter 16
4.2 Receiver 17
Chapter 5: Advantages of LiFi 18
Chapter 6: Applications of LiFi 20
Chapter 7: Conclusion 22
Chapter 8: Future Scope 24
Reference
iii

ABSTRACT
With increasing demands for faster and more secure wireless
communications, there is a pressing need for a new medium of wireless
communication as the radio spectrum is already crowded. Visible light is a
medium that can address both of these needs. It is a relatively new
technology with great potential. This project was completed to develop a
working visible light communication system and demonstrate the
transmission capabilities of such a system. This year’s team set a goal to
surpass the previous years team in transmission speed, range, and size. Of
these goals, transmission speed and range were both achieved, while the
transmission of a large audio file was deemed not possible based off the
difficulties the team encountered while processing large amounts of data.
iv

LIST OF FIGURES
Topic Name Page No.
2.1 Working of LiFi 4
3.1 Arduino Nano Ckt Layouts 7
3.2 16x2 LCD Display 9
3.3 4x4 Keypad 10
3.4 Matrix Ckt Diagram 11
3.5 Photodiode 11
3.6 Transistor 12
3.7 7805CV Voltage Converter 13
3.8 Single Layer PCB 14
4.1 Tx Circuit Diagram 16
4.2 Rx Circuit Diagram 17
v

LIST OF TABLES
Topic Name Page No.
3.1 Pin Description of Arduino Nano 8
3.2 Pin Description of LCD Display 10
3.3 Pin Discription of 7805CV 13
vi

Introduction
Li-Fi (Light Fidelity) is a VLC, visible light communication technology,
developed by the team of scientists including professor Haas at the
University of Edinburg and deals with transfer of data through illumination
by taking fiber out of optics by sending data through a LED light bulb that
varies in the intensity faster than a human eye can follow. Dr Haas amazed
people by streaming HD video from a standard LED lamp, at TED Global
in July 2011 and thereby coined the term Li-Fi. Li-Fi is now part of visible
light communication (VLC) PAN IEEE 802.15.7 standard. It can be very
easily explained as, if the LED is ON, you are transmitting the data means
you transmit a digital 1 ; and if the LED is OFF you transmit a digital 0,or
null, or simply no data transfer happens. As one can switch them on and off
very frequently one can transmit data easily because the LEDs intensity is
modulated so rapidly that human eye cannot notice, so the output in form of
light appears constant and hence offering permanent connectivity. Mixtures
of red, blue, green LEDs are also used by some groups to encode different
data channels by altering the light frequencies. In simple terms we can
consider it to be a light based Wi-Fi which has achieved blistering high
speed in the labs at Heinrich Hertz institute in Berlin, Germany of around
500 megabytes per second using a standard white-light LED. So quiet
obviously, modems would be replaced by transceiver fitted LED lamps
which can serve both in purposes of lightening the room as well as
transmitting the data. The technology uses a part of an electromagnetic
spectrum and was demonstrated at 2012 consumer electronics show in Las
Vegas whereby a pair of Cisco smart phone was used to exchange data
using light of varying intensity from their screens.
2

Working of LiFi
Fig 2.1 Working of Lifi
It is implemented by using a light bulb at the downlink transmitter.
Normally the light bulb glows at a constant current supply however fast and
subtle variations in current can be made to produce the optical outputs since
it just uses the light, hence can be easily applied in aircrafts or hospitals or
any such area where radio frequency communication is often problematic.
The operation procedure is very simple-, if the LED is on you transmit a
digital 1, if it is off you transmit a 0. The LED can be switched on and off
very quickly hence providing nice opportunities to transmit data. Hence all
that is required id some LED and a controller that code data into those
LEDs flicker depending upon the data we want to encode. The more LEDs
in your lamp, the more data it can process. To further get an clear idea of
what is said above let us consider a IR remote which sends data stream at
rate of 10000-20000 bps. Now replace the IR LED with a light box
4

containing a large LED array which is capable of sending thousands of such
streams at very fast rate. LEDs are found in traffic and street lights, car
brake lights, remote control units and countless other applications. So
visible light communication not only solves the problem related to lack of
spectrum space but also enable novel application because this spectrum is
unused and not regulated thus can be used for communication at very high
speeds. This method of using rapid pulses of light to transmit information
wirelessly, technically referred to as visible light communication (VLC) has
a potential to compete with Wi-Fi and hence inspired the characterization of
Li-Fi.
5

Main Components
3.1 Arduino Nano :-
The Arduino Nano is a small, complete, and breadboard-friendly board
based on the ATmega328 (Arduino Nano 3.x) or ATmega168 (Arduino
Nano 2.x). It has more or less the same functionality of the Arduino
Duemilanove, but in a different package.
Fig 3.1 Arduino Nano Ckt Layouts
It lacks only a DC power jack, and works with a Mini-B USB cable instead
of a standard one. The Arduino Nano can be powered via the Mini-B USB
connection, 6-20V unregulated external power supply (pin 30), or 5V
regulated external power supply (pin 27). The power source is
automatically selected to the highest voltage source. The Arduino Nano,
as the name suggests is a compact, complete and bread-board friendly
microcontroller board. The Nano board weighs around 7 grams with
dimensions of 4.5 cms to 1.8 cms (L to B). Arduino Nano has similar
functionalities as Arduino Duemilanove but with a different package. The
Nano is inbuilt with the ATmega328P microcontroller, same as the
Arduino UNO.
7

Table 3.1 Pin Description of Arduino Nano
Pin Category Pin Name Details
Power
Vin, 3.3V,
5V,GND
Vin: Input voltage to Arduino when using an external
power source (6-12V).
5V: Regulated power supply used to power
microcontroller and other components on the board.
3.3V: 3.3V supply generated by on-board voltage
regulator. Maximum current draw is 50mA.
GND: Ground pins.
Reset Reset Resets the microcontroller.
Analog Pins A0 – A7 Used to measure analog voltage in the range of 0-5V
Input/Output
Pins
Digital Pins D0 -
D13
Can be used as input or output pins. 0V (low) and 5V
(high)
Serial Rx, Tx Used to receive and transmit TTL serial data.
External
Interrupts
2, 3 To trigger an interrupt.
PWM 3, 5, 6, 9, 11 Provides 8-bit PWM output.
SPI
10 (SS), 11
(MOSI), 12
(MISO) and 13
(SCK)
Used for SPI communication.
Inbuilt LED 13 To turn on the inbuilt LED.
IIC
A4 (SDA), A5
(SCA)
Used for TWI communication.
AREF AREF To provide reference voltage for input voltage.
8

3.2 16X2 LCD Display :-
LCD (Liquid Crystal Display) screen is an electronic display module and
find a wide range of applications. A 16x2 LCD display is very basic module
and is very commonly used in various devices and circuits. These modules
are preferred over seven segments and other multi segment LEDs. The
reasons being: LCDs are economical; easily programmable; have no
limitation of displaying special & even custom characters (unlike in seven
segments), animations and so on.
Fig 3.2 16x2 LCD Display
16×2 LCD is named so because; it has 16 Columns and 2 Rows. There are a
lot of combinations available like, 8×1, 8×2, 10×2, 16×1, etc. but the most
used one is the 16×2 LCD. So, it will have (16×2=32) 32 characters in total
and each character will be made of 5×8 Pixel Dots.
A 16x2 LCD means it can display 16 characters per line and there are 2
such lines. In this LCD each character is displayed in 5x7 pixel matrix. This
LCD has two registers, namely, Command and Data.
The command register stores the command instructions given to the LCD. A
command is an instruction given to LCD to do a predefined task like
initializing it, clearing its screen, setting the cursor position, controlling
display etc. The data register stores the data to be displayed on the LCD.
9

Table 3.2 Pin Descriptions of 16x2 LCD Display
Pin
No
Function Name
1 Ground (0V) Ground
2 Supply voltage; 5V (4.7V – 5.3V) Vcc
3 Contrast adjustment; through a variable resistor VEE
4
Selects command register when low; and data register
when high
Register
Select
5
Low to write to the register; High to read from the
register
Read/write
6
Sends data to data pins when a high to low pulse is
given
Enable
7
8-bit data pins
DB0
8 DB1
9 DB2
10 DB3
11 DB4
12 DB5
13 DB6
14 DB7
15 Backlight VCC (5V) Led+
16 Backlight Ground (0V) Led-
3.3 4X4 Keypad :-
Fig 3.3 4x4 Keypad
10

The keypad is an arrangement of 16 push button switches in the form of a
4x4 matrix. The keypad consists of numbers 0,1,2,3,4,5,6,7,8,9 and letters
A, B, C, D,*, #. Column scanning method is used to identify the pressed
key. It is used to provide input to microcontroller units. Membrane-type
keypads are an economical solution for many applications. They are quite
thin and can easily be mounted wherever they are needed.
Fig 3.4 Matrix Ckt Diagram
Initially all switches are assumed to be released. So there is no connection
between the rows and columns. When any one of the switches are
pressed, the corresponding row and column are connected (short
circuited). This will drive that column pin (initially high) low. Using this
logic, the button press can be detected. The colors red and black is for
logic high and low respectively.
3.4 Photodiode :-
Fig 3.5 Photodiode
11

A photodiode is a semiconductor device that converts light into current.
The current is generated when photons are absorbed in the photodiode. A
small amount of current is also produced when no light is present.
Photodiodes may contain optical filters, built-in lenses, and may have
large or small surface areas. Photodiodes usually have a slower response
time as their surface area increases. The common, traditional solar cell
used to generate electric solar power is a large area photodiode. When a
light beam strikes the photodiode, it conducts an amount of reverse
current that is proportional to the light intensity (irradiance).
3.5 Transistor :-
Fig 3.6 Transistor
A transistor is a device that regulates current or voltage flow and acts as a
switch or gate for electronic signals. Transistors consist of three layers of a
semiconductor material, each capable of carrying a current. Transistors are
created through a chemical process known as doping, where the
semiconductive material either gains an extra negative charge (N-type) or
extra positive charge (P-type). There are two configurations for this, either
PNP or NPN with the middle material acting as the base or flow control.
Transistors are the basic elements in integrated circuits (IC), which consist
of very large numbers of transistors interconnected with circuitry and
baked into a single silicon microchip.
12

3.6 7805CV Voltage Converter :-
Fig 3.7 7805CV Voltage Converter
Voltage sources in a circuit may have fluctuations resulting in not
providing fixed voltage outputs. A voltage regulator IC maintains the
output voltage at a constant value. 7805 IC, a member of 78xx series of
fixed linear voltage regulators used to maintain such fluctuations, is a
popular voltage regulator integrated circuit (IC). The xx in 78xx indicates
the output voltage it provides. 7805 IC provides +5 volts regulated power
supply with provisions to add a heat sink.
Table 3.3 Pinout of 7805CV
Pin
No.
Pin Function Description
1 INPUT
Input voltage (7V-
35V)
In this pin of the IC positive
unregulated voltage is
given in regulation.
2 GROUND Ground (0V)
In this pin where the
ground is given. This pin is
neutral for equally the input
and output.
3 OUTPUT
Regulated output; 5V
(4.8V-5.2V)
The output of the regulated
5V volt is taken out at this
pin of the IC regulator.
13

3.7 Single Layer PCB (Printed Circuit Board) :-
Fig 3.8 Single Layer PCB
It is one that is made out of a single layer of base material or substrate.
One side of the base material is coated with a thin layer of metal. Copper
is the most common coating due to how well it functions as an electrical
conductor. Once the copper base plating is applied, a protective solder
mask is usually applied, followed by the last silk-screen to mark out all of
the elements on the board. Surface mount PCBs don't utilize wires as
connectors. Instead, many small leads are soldered directly to the board,
meaning that the board itself is used as a wiring surface for the different
components. This allows circuits to be completed using less space, freeing
up space to allow the board to complete more functions, usually at higher
speeds and a lighter weight than a through-hole board would allow.
14

Circuit Diagram
4.1 Transmitter -
Fig 4.1 Tx Ckt Diagram
At Transmitter section 4x4 Keypad and 16x2 LCD Display is connected to
the Arduino Nano. Arduino is powered by either its USB B mini port or an
external power supply of +5V. As texts are entered on the keypad it will be
displayed on the LCD Display. Since to allow arduino to perform such
tasks some codes are uploaded through computer to arduino. All this
calculations are performed by Arduino Nano and creates an output on the
display.An led is also connected to the arduino which blinks as the input is
16

given at keypad. This blinking is received by the receiver section which
converts it into digital form and thus displaying on the receivers end lcd
display.
4.2 Receiver Circuit –
Fig 4.2 Rx Ckt Diagram
This section of the also contain an arduino and an LCD Display. The text
that has been received from the transmittion section is being processed
by the arduino and is converted into digital form that is than displayed on
the lcd display. The input data is received by a photosensitive circuit
consisting of an LDR (light dependent resistor) which is a photo sensitive
resistor, an Op-Amp which sends this data to the arduino where it is being
processed and then displayed on the lcd display.
17

Advantages of LiFi
1. Capacity:
10000 times more spectrum than RW.
LEDs are already present.
So we have the infrastructure available and already installed.
2. Efficiency:
Data through illumination and thus data transmission comes for free.
LED light consumes less energy.
highly efficient.
3. Availability:
Wherever there is a light source, there can be Internet. Light bulbs are
present everywhere – in homes, offices, shops, malls and even planes,
meaning that high-speed data transmission could be available
everywhere.
4. Security:
Light waves dont penetrate through walls.
cant be intercepted & misused.
Data is present where there is light.
5. Cost:
Instead of running close to a mile worth of cable, the LED-powered
Li-Fi connection could be used to beam the information directly to the
destination. Using a point-to-point array, office buildings can stay
connected to each other without the use of additional cables being laid
from one access point to another.
19

Applications of Li-Fi
 Can be used in places where it is difficult to lay the optical fiber like
hospitals. In operation theatre Li-Fi can be used for modern medical
instruments.
 In traffic signals Li-Fi can be used which will communicate with LED
lights of the cars and accident numbers can be decreased.
 Thousand and millions of street lamps can be transferred to LiFi Lamps
to transfer data.
 In aircraft Li-Fi can be used for data transmission.
 It can be used in petroleum or chemical plants where other transmission
or frequencies could be hazardous.
 Hospitals are a specific case of an environment where both EMI
sensitivity and security of data are issues. Li-Fi can enable the better
deployment of secure networked medical instruments, patient records,
etc.
 Radio waves are quickly absorbed in water, preventing underwater radio
communications, but light can penetrate for large distances. Therefore,
Li-Fi can enable communication from diver to diver, diver to mini-sub,
diver to drilling rig, etc
21

Conclusion
With the growing technology and increasing use of the internet services,
possibities are very high that use of Lifi Technology will be soon in
practice. Every bulb will be replaced by Lifi bulbs and might be used like a
wifi hotspot for the transmission of data. Using Lifi technology will grant a
cleaner, greener and brighter future and environment. The concept of lifi
is spreading so fast as it is easy to use, it is attracting interest of people.
The use of lifi technology gives a very golden opportunity to replace or to
give alternative to the radio based wireless technologies. As the number
of people and the access of internet is increasing on such a large scale ,
accessing internet through Wi-Fi will soon be insufficient as the usage is
increasing but the bandwidth remains the same. As network traffic will
increase it will result in lowering the speed of accessing the internet thus
more increasing prices. Thus the use of Lifi will increase thespeed of data
transfer and also it is accessible in many banned places thus it will be
available for all.
23

Future scope
As light is everywhere and free to use possibities increases to a great
extent of the use of Li-Fi technology. If this technology comes to practice
each lifi bulb will be used as Wi-Fi hotspot to transmit wireless data. As
the lifi technology will be used which will lead to a cleaner, greener, safer
and bright future and environment. The concept of lifi is attracting many
people as it is free to use without any license and faster means of data
transfer. If it develops fasterpeople will more and more use this
technology instead of Wi-Fi.
25

Reference
https://www.lifi-centre.com/about-li-fi/applications/
https://electronicsforu.com/resources/learn-electronics/
https://whatis.techtarget.com/definition/LiFi
https://en.wikipedia.org/wiki/Li-Fi
26

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