IRJET - Li-Fi based Home/Office Computerization System

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 07 Issue: 04 | Apr 2020 www.irjet.net p-ISSN: 2395-0072
© 2020, IRJET | Impact Factor value: 7.34 | ISO 9001:2008 Certified Journal | Page 1774
Li-Fi Based Home/Office Computerization System
Ramya D D1, Meghana R2, Ranjitha A3, Zunera Tahera4
1-4U.G. Students, Dept. of Electrical and electronics Engineering, HMSIT Tumakuru, Karnataka, India
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Abstract - In the present era, Wi-Fi is the most trending
domain. As internet users almost double everyyear,thereisan
enormous load on radio spectrum that leads to congestion. To
get better bandwidth, efficiency and speed, a new technology
Li-Fi has evolved. Li-Fi stands for Light Fidelity. It is a
bidirectional and wireless mode of communication usinglight.
It uses the unused visible spectrum and reduces the load on
radio spectrum. Li-Fi can be simply put to be Wi-Fi but instead
of radio waves light is used as a medium. Here, data is
transmitted using light whose intensity varies faster than
human eye to capture. Instead of usingmodems, Li-Fi usesLED
bulbs with transceiver. Data transmission in Li-Fi isabout100
times faster than Wi-Fi. Here, in this paperweexploretheneed
for Li-Fi in home/office automation.
Key Words: Audio Jack, DTMF Encoder, Power LED,
Microcontroller AT89C51, LCD Display, Pre-Amplifier,
Power Amplifier, Modulator, Keyboard, Device
controller.
1.INTRODUCTION
Light Fidelity (Li-Fi) is future technology whichreplacesthe
Wi-Fi. Because Li-Fi overcomes disadvantages of Wi-Fi like
Data Transfer speed of Li-Fi is more than 1Gbps while in Wi-
Fi it is about 150 Mbps. Li-Fi uses light as a carrier but Wi-Fi
uses radio Spectrum. In Li-Fi Visible light Spectrum has
10,000 broad spectrums in comparison of radio frequency.
Operating Frequency in Li-Fi is Hundreds of TeraHz where
as in Wi-Fi it is 2.4 GHz. Li-Fi is Cheaper than Wi-Fi because
free band doesn’t need license and it uses light. Li-Fi is a
bidirectional, high speed and fully networked wireless
communication technology similar to Wi-Fi. This term was
developed by Harald Haas and is a form of visible light
communication and a subset of optical wireless
communications (OWC) and could be a complement to RF
communication (Wi-Fi or Cellular network), or even a
replacement in contexts of data broadcasting. It is so far
measured to be about 100 times faster than some Wi-Fi
implementations, reaching speeds of 224 gigabits per
second. Li-Fi technology in the audio transmission is must
faster and secured communication. In Li-Fi based
Home/Office automation we can control number of devices
using Android application, embedded controller plays
important role for switching the device. In future this
technology can be used in industry automation for
controlling various machineries and robotics. Nowadays
approximately 5 million mobile phones are transmitted
higher than 600 terabytes of data in every month and
currently there are 1.4 billion base station available that
inherent more energy and there should be less than 5
percent of efficiency, this all explains that usage of wireless
has been achieved maximum utility.
1.1 Aim and Objectives
The prime objective of the project is to create an application
that transmits data be it text, audio or video using Li-Fi
technology for coping with the limited bandwidth problem
we face in RF (Radio frequency) signals. For better, efficient,
secure and a faster connection Li-Fi is used. One of the
advantages of usingLi-Fi over Wi-Fi isthatitavoidsradiation
produced by Wi-Fi. The goal of our project is to transfer data
with faster speed which is not easy to achieve through Wi-Fi
and see whether transmission is possible through various
mediums or not. Li-FicanbethoughtsanalternativeforWi-Fi
which uses light as a medium to transmit data. We aimed at
the transmission of data via Li-Fi and all the possible aspects
of transmitting datavialightthroughvariousmediumswhich
will give us a broad idea of where and how we can use Li-Fi
for transmission of data.
1.2 Requisite
Li-Fi using visible light instead of gigahertz radio waves.
Nowadays approximately 5 million mobile phones are
transmitted higher than 600 terabytes of data in every
month and currently there are 1.4 billion base station
available that inherent more energy and thereshouldbeless
than 5 percent of efficiency, this all explains that usage of
wireless has been achieved maximum utility. It is free of
wires and there will be no box installed as Wi-Fi. The binary
numbers should be transmitted into light pulse. It can be
through tiny LED bulbs on and off a million of times per
second. The explorers of data transmission through blinking
of LED which translates up to 10 Gbps with the help of
wireless internet. These gain come at a five-fold transits
currently offering fiber optics,Luminousrouterisusedtoget
the maximum gain of this technology, that have the capacity
to emit the binary signals. Li-Fi is not visible to eye so it
won’t ever replace Wi-Fi, but it could overcome it nicely. It
will be very easy in our house where every light will act as a
wireless network bridge, instead of trying to find theperfect
Wi-Fi router. A Construction of Li-Fi System Compared to
Wi-Fi, Li-Fi is a cheap and fast optical technology. Visible
Light Communication (VLC) is the basis for Li-Fi.VLC is a
data communication media, which depends on visible light
between 400 THz (780 nm) - 800 THz (375 nm). It acts as an
optical carrier for data transmission and illumination which
uses fast signals of light for transmission without wires.

2. TECHNIQUE
Transceiver is a Block that act as a transmitter and receiver
at the same time. This transceiverconsists ofLEDtotransmit
the light and photodiode to receive the light. Amplifier is
embedded to strength the power of light received from the
photodiode. The modem is used to modulate and
demodulate the signal. The signal that comes from the
photodiode is analog and it converts into digital in the
modem. While the signal that ready to transmit, the digital
signal convert into analog signal in the modem and sent by
LED. The driver before the LED operates to drivethecurrent
of the LED in order to get the flickering. The flickering is
functioning the LED for data transmission, if LED is ON then
it transmits digital ‘1’ and if OFF, it transmitsdigital ‘0’[4][5].
Fig-1: Block diagram of Transmitter
Fig-2: Block diagram of Receiver
The Li-Fi system consists of mainly two parts, the
transmitter and the receiver. LED light is used as signal
source between two end systems. Data is carried by the
modulated light from the LED. The microprocessor unit
(MPU) system modulates and demodulates data at
transmitter and receiver ends respectively. The transmitter
part modulates the input signal with the required time
period and transmits the data in the form of 1's and0's using
a LED bulb. These 1's and 0's are nothing but the flashes of
the bulb. The receiver part catches these flashes using a
photodiode and amplifies the signal to produce the output.
Li-Fi is implemented usingwhiteLEDlightbulbsatdownlink
transmitter. An array of LEDs can also be used for parallel
data transmission and different colored LEDs to alter the
LED frequency so that data are encrypted for different
frequency.
Fig-3: 4x4 Key Matrix.
Above figure No. 5.5 indicates the 4x4 key matrix keyboards,
used to generate the DTMF codecombinations.Itcontains16
keys. The key combination can send the particular frequency
to switch ON or OFF the Device. According to these key
combinations the particulardevices are switched ON or OFF.
Table -1: Conditions for working
Sr. No. Parameter Observations
1) Max. Length of Communication
between Transmitter & Receiver.
5 Meters
2) Response time of relay after key
pressed.
10ms
3. CONCLUSIONS
The most of the dependent upon ‘the cloud’ or our own
‘media services’ to store all of our files, including movies,
photos, audio and video devices, games, the more and most
bandwidth and speed should be needed to access this data.
Therefore RF-based technologies such as today’s Wi-Fi are
not the optimal way. In addition, Wi-Fi may not be the most
efficient way to provide new desired capabilities such as
precision indoor positioning and gesture recognition. The
optical wireless technologies, sometimes called visible light
communication (VLC), andmore recentlyreferredtoas Li-Fi.
On the other hand, offer an entirely new paradigm in
wireless technologies in the terms of communication speed,
usability and flexibility, reliability. VLC is the possible
solution to the global wireless spectrum shortage.LI-FI
technology is a fast and cheap optical version of Wi-Fi.

REFERENCES
[1] http://en.wikipedia.org/wiki/Li-Fi.
[2] http://www.seminarpaper.com/2013/14/seminar-
report-on-li-fi-html
[3] www.lificonsorting.org/
[4] http://edition.cnn.com/2012/09/28/tech/lifi-haas-
innovation
[5] http://www.extremetech.com/extreme/147339-
micro-led-lifi- whereevery-light-source-in-the-world-
is-also-tv-and-provides-gigabit-internet access.
[6] http://www.ispreview.co.uk/index.php/2013/01/tin
y-led-lights-set-todeliver-wifi-style-internet-
communications.html

IRJET - Li-Fi based Home/Office Computerization System

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