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International Journal of Mechanical Engineering and Technology (IJMET)
Volume 10, Issue 03, April 2019, pp. 1483-1491. Article ID: IJMET_10_03_150
Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=10&IType=3
ISSN Print: 0976-6340 and ISSN Online: 0976-6359
© IAEME Publication Scopus Indexed
A LI-FI TECHNOLOGY BASED SMART
VEHICLE
N. Selvarani, P. Malathy, G. Devi and J. Velmurugan
Department of Electrical and Electronics Engineering,
PSNA College of Engineering and Technology,Dindigul, Tamil Nadu, India.
ABSTRACT
Smart car deals with the smart collision avoidance between the vehicles using
visible light communication. The basic concept behind this technique is that the data
can be transferred through LED light by varying light intensities faster than the human
eyes can perceive. This technology uses a part of the electromagnetic spectrum that is
still not greatly utilized- The Visible Spectrum, instead of Gigahertz radio waves for
data transfer. Light Fidelity (Li-Fi) has got a much broader spectrum for transmission
compared to conventional methods of wireless communications that rely on radio
waves.
By Communication through visible light, Li-Fi technology has the possibility to
change how to access the Internet, stream videos, receive emails and much more.
Security would not be an issue as data can’t be accessed in the absence of light. As a
result, it can be used in high security military areas where RF communication is prone
to eavesdropping. By adding new and unutilized bandwidth of visible light to the
currently available radio waves for data transfer, Li-Fi can play a major role in
relieving the heavy loads which the current wireless system is facing. By the use of this
technology, smart cars have been implemented.
Key words: Light Fidelity technology, Microcontroller, Arduino, alcohol sensor,
ultrasonic sensor.
Cite this Article N. Selvarani, P. Malathy, G. Devi and J. Velmurugan, A Li-Fi
Technology Based Smart Vehicle, International Journal of Mechanical Engineering and
Technology, 10(3), 2019, pp. 1483-1491
http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=10&IType=3
1. INTRODUCTION
Li-Fi is a new paradigm for short range wireless technology to provide connectivity within a
localized data-centric environment. Li-Fi is a transmission of data through illumination, sending
data through a LED light bulb that varies in a intensity faster than the human eyes can follow.
Li-Fi has reached speeds of 224Gbps, which is far faster than typical Wi-Fi connection offers.
In fact, it’s roughly 100 times faster, which is useful now but as data demands grow it could
become near essential. There is far more spectrum available for use with Li-Fi than Wi-Fi, as
A Li-Fi Technology Based Smart Vehicle
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the visible light spectrum is 10,000 times larger than the entire radio frequency spectrum and is
unregulated so the technology doesn’t need to be licensed. This makes it hugely important for
5G as that also requires a large amount of radio-spectrum. By offloading as many tasks to Li-
Fi as possible, more radio spectrum can be freed up for use with 5G.
In the conventional system, the vehicle to vehicle communication is done by the means
of Wi-Fi. This is modified by the use of Li-Fi which uses visible light communication
technology. Li-Fi is more secure compared with the Wi-Fi and offers a high speed data transfer.
Obstacle detection with intimation through alarm unit from front vehicle to back vehicle using
Li-Fi communication. During this process, the information regarding the alcohol consumption
of the vehicle driver also gets detected using the alcohol sensor and is stored in the
microcontroller and gets transferred to the back vehicle. Deep Steep Curve information or other
scenarios where overtaking is not possible, is intimated to the back vehicle from front vehicle
driver. This makes the driver to drive safely.
The scope of this work is to design a collision detection system for smart car using Li-
Fi and ultrasonic sensor on the Arduino platform. This design consists of ultrasonic sensor,
Arduino processor, and Li-Fi circuit. Ultrasonic is used for measurement of distance between
vehicles and Arduino processes the data and gets decisions accordingly. The data transmission
between the vehicles ensued using Li-Fi transmitter circuit and Li-Fi receiver circuit. The
transmitter circuit will be mounted on tail lights of leading car and the receiver circuit will be
mounted on the front side of car that follows. Using visible light communication the transmitter
circuit will transmit the calculated distance and the information will be received by the receiver
circuit of second car and based on the information received the speed of the second car will be
changed in order to avoid the collision.
2. HARDWARE DESCRIPTION
2.1. Proposed Li-Fi Technique
Li-Fi is a new way of wireless communication that uses LED lights to transmit data wirelessly.
Transmission of data is one of the most important day to day activities in the fast growing world.
The current wireless networks that connect us to the Internet are very slow when multiple
devices are connected. Also with the increase in the number of devices which access the
Internet, the availability of fixed bandwidth makes it much more difficult to enjoy high data
transfer rates and to connect a secure network. Radio waves are just a small part of the
electromagnetic spectrum available for data transfer. Li-Fi has got a much broader spectrum for
transmission compared to conventional methods of wireless communications that rely on radio
waves. The basic ideology behind this technology is that the data can be transferred through
LED light by varying light intensities faster than the human eyes can perceive. This technology
uses a part of the electromagnetic spectrum that is still not greatly utilized- the Visible
Spectrum, instead of Gigahertz radio waves for data transfer. The Li-Fi transmitter and receiver
is shown in Fig 1. The idea of Li-Fi was introduced for the first time by a German physicist
Harald Hass in the TED (Technology, Entertainment, Design) Global talk on Visible Light
Communication (VLC) in July 2011, by referring to it as “data through illumination”. He used
a table lamp with an LED bulb to transmit a video of a blooming flower that was then projected
onto a screen.
In simple terms, Li-Fi can be thought of as a light-based Wi-Fi i.e. instead of radio waves
it uses light to transmit data. In place of Wi-Fi modems, Li-Fi would use transceivers fitted with
LED lamps that could light a room as well as transmit and receive information. By adding new
and unutilized bandwidth of visible light to the currently available radio waves for data transfer,
Li-Fi can play a major role in relieving the heavy loads which the current wireless system is
N. Selvarani, P. Malathy, G. Devi and J. Velmurugan
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facing. Thus it may offer additional frequency band of the order of 400 THz compared to that
available in RF communication which is about 300 GHz. Also, as the Li-Fi uses the visible
spectrum, it will help alleviate concerns that the electromagnetic waves coming with Wi-Fi
could adversely affect our health. By Communication through visible light, Li-Fi technology
has the possibility to change how we access the Internet, stream videos, receive emails and
much more. Security would not be an issue as data can’t be accessed in the absence of light.
Figure 1 Li-Fi Transmitter and Receiver
2.2. Li-Fi transmitter
Fig. 2 represents the block diagram of the Li-Fi transmitter circuit. The transmitter circuit is
usually placed on the tail light of the car. This system as a whole is used to transmit the data to
the receiver circuit. The main components of this section contains an ultrasonic sensor, alcohol
sensor, overtake guidance switch and an LCD display..
Figure 2 Block Diagram of Li-Fi Transmitter
2.3. Li-Fi receiver
Fig. 3 represents the block diagram of the Li-Fi receiver circuit. This is usually mounted on the
head light of the car. This is used to receive the information from the transmitter section. The
main components of this section are power supply, microcontroller, LCD display, buzzer, Li-
Fi receiver, motor driving circuit.
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Figure 3 Block Diagram of Li-Fi receiver
2.4. Operating Principle
The hardware set up consists of a transmitter and a receiver section. The transmitter is usually
placed on the tail light of the car. The transmitter section consists of ultrasonic sensor which is
used to sense the distance between the cars. The alcohol gas sensor is used to detect the drunkard
drive and the overtake guidance switch is used to indicate in case of overtaking. The information
passed is received on the receiver circuit. At the normal conditions when there is no indication
of overtaking or drunkard drive and the distance between the cars is greater than 30cm the LCD
of the back car receives the message of normal drive. The data from the transmitter reaches the
receiver by the Li-Fi circuit. The data passes at a rate of 9600bits/sec.
When the alcohol sensor detects the presence of alcohol, the indication of alcohol drive is
send to the back car. The overtaking guidance is also passed through the transmitter circuit.
When the back car approaches forward, the distance between the two cars reduces as a result
the command for speed reduction is passed. When the distance is between 20- 25 cm, the
indication of slow speed is passed and when the distance is less than 20cm the indication of
stop is displayed in the back car.
3. SOFTWARE DESCRIPTION
3.1. Embedded C
Embedded C is a set of language extensions for the C programming language by the C Standards
Committee to address commonality issues that exist between C extensions for different
embedded systems. Embedded C programming requires nonstandard extensions to the C
language in order to support exotic features such as fixed-point arithmetic, multiple distinct
memory banks, and basic I/O operations. In 2008, the C Standards Committee extended the C
language to address these issues by providing a common standard for all implementations to
adhere to. It includes a number of features not available in normal C, such as fixed-point
arithmetic, named address spaces and basic I/O hardware addressing. Embedded C uses most
of the syntax and semantics of standard C, e.g., main () function, variable definition, data type
declaration, conditional statements (if, switch case), loops (while, for), functions, arrays and
strings, structures and union, bit operations, macros, etc.
Embedded systems programming is different from developing applications on a desktop
computers. Key characteristics of an embedded system, when compared to PCs, are as follows:
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Embedded devices have resource constraints(limited ROM, limited RAM, limited stack
space, less processing power)Components used in embedded system and PCs are different;
embedded systems typically uses smaller, less power consuming components. Embedded
systems are more tied to the hardware. Two salient features of Embedded Programming are
code speed and code size. Code speed is governed by the processing power, timing constraints,
whereas code size is governed by available program memory and use of programming language.
Goal of embedded system programming is to get maximum features in minimum space and
minimum time. Some of the merits of are it is small and reasonably simpler to learn, understand,
program and debug. C Compilers are available for almost all embedded devices in use today,
and there is a large pool of experienced C programmers.
3.2. Arduino
Arduino programs are written in the Arduino Integrated Development Environment (IDE).
Arduino IDE is special software running on your system that allows you to write sketches
(synonym for program in Arduino language) for different Arduino boards. The Arduino
programming language is based on a very simple hardware programming language called
processing, which is similar to the C language. After the sketch is written in the Arduino IDE,
it should be uploaded on the Arduino board for execution.
Arduino is an open-source electronics platform based on easy-to-use hardware and
software. Arduino boards are able to read inputs - light on a sensor, a finger on a button, or a
Twitter message - and turn it into an output - activating a motor, turning on an LED, publishing
something online.
Over the years Arduino has been the brain of thousands of projects, from everyday objects
to complex scientific instruments. A worldwide community of makers - students, hobbyists,
artists, programmers, and professionals - has gathered around this open-source platform, their
contributions have added up to an incredible amount of accessible knowledge that can be of
great help to novices and experts alike.
Arduino was invented at the Ivrea Interaction Design Institute as an easy tool for fast
prototyping, aimed at students without a background in electronics and programming. As soon
as it reached a wider community, the Arduino board started changing to adapt to new needs and
challenges, differentiating its offer from simple 8-bit boards to products for IoT applications,
wearable, 3D printing, and embedded environments. All Arduino boards are completely open-
source, empowering users to build them independently and eventually adapt them to their
particular needs. The software, too, is open-source, and it is growing through the contributions
of users worldwide.
Some of the merits of Arduino Simple and accessible user experience, Arduino has been
used in thousands of different projects and applications. The Arduino software is easy-to-use
for beginners, yet flexible enough for advanced users. It runs on Mac, Windows, and Linux.
Teachers and students use it to build low cost scientific instruments, to prove chemistry and
physics principles, or to get started with programming and robotics. Designers and architects
build interactive prototypes, musicians and artists use it for installations and to experiment with
new musical instruments.
4. HARDWARE PROTOTYPE