Research Article

May 2016

Special Issue on International Conference on Advances in Engineering (ICAE) -2016

Conference Held at Hotel Magaji Orchid, Sheshadripuram, Bengaluru, India.

© 2016, IJERMT All Rights Reserved Page | 82

International Journal of

Emerging Research in Management &Technology

ISSN: 2278-9359 (Volume-5, Issue-5)

Li-fi Based Blind Indoor Navigation System for Visually

Impaired People Syeda Mahin

1, Srikanth Kumar V

2, Amith Kumar.R

3, Sumera Banu.M

4, Sukumar.Sv

5

1, 2, 3, 4 Final year students, Dept. of ECE, C.Byregowda Institute of Technology, Kolar, Karnataka, India

5 Assistance professor and guide, Dept. of ECE, C.Byregowda Institute of Technology, Kolar, Karnataka, India

Abstract: Li-Fi (Light-Fidelity) is transmission of data using visible light by sending data through a LED light bulb

that varies in intensity faster than the human eye can follow.The term Li-Fi refers to visible light communication

(VLC) technology that uses light as a medium to deliver high-speed communication in a manner similar to Wi-Fi.

The Wi-Fi is useful for general wireless coverage within buildings while Li-Fi is ideal for high density wireless data

coverage in confined areas where there are no obstacles. Since visible light is present everywhere, the main idea of

our paper is to create internal navigation systems for the bigger areas to create automatic navigation for the visitors

who are visually impaired using Li-Fi technology.

Keywords: Light Fidelity; LED; VLC; Wi-Fi; Bandwidth; photo detector

I. INTRODUCTION

The Li-Fi technology can transfer the data through LEDs. It is a high speed and low cost wireless communication

system, compared to Wi-Fi. It can provide high security, large bandwidth, and low cost.

Li-Fi uses common household LED (light emitting diodes) light bulbs to enable data transfer, boasting speeds of up to

224 gigabits per second.

Light Fidelity (Li-Fi) is a bidirectional, high speed and fully networked wireless communication technology similar to

Wi-Fi. The term was coined 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.Li-Fi can be considered better than Wi-Fi because there are some

limitations in Wi-Fi. Wi-Fi uses 2.4 – 5 GHz radio frequencies to deliver wireless internet access and its bandwidth is

limited to 50-100 Mbps.This technology has been proposed as a solution to the RF bandwidth limitations.

Indoor navigation is convenient to everyone and it is especially indispensable for the visually impaired. Li-Fi makes use

of a free, unlicensed spectrum and is not affected by RF noise. Moreover, most indoor locations would have a sufficient

amount of light sources and provide additional security since Li-Fi cannot penetrate through walls.

II. SYSTEM IMPLEMENTATION

WORKING OF LI-FI:

Figure-1.Design of LED bulb.

At the heart of this technology, a new generation of high-brightness light-emitting diodes. Very simply, if the LED is

ON, user can transmit a digital string of 1, if it’s OFF then user can transmit a string of 0. It can be switched ON and OFF

very quickly, which gives instant opportunity for transmitting data.

It is possible to encode data in the light by varying the rate at which the LEDs flicker ON and OFF to pass different

strings of 1s and 0s. The modulation is so fast that the human eye doesn’t notice. There are over 14 billion light bulbs

used across the world, which needs to be replaced with LEDs ones that transmit data.

Mahin et al., International Journal of Emerging Research in Management &Technology

ISSN: 2278-9359 (Volume-5, Issue-5)

© 2016, IJERMT All Rights Reserved Page | 83

Fig 2 Working of li-fi

As shown in figure data is fed into LED light bulbs, it then sends data at rapid speeds to photodiode. The tiny changes in

rapid dimming of LED bulbs is then converted by the receiver into electrical signal. The signal is then converted back

into a binary stream that we could recognise as audio and video applications.

III. BLOCK DIAGRAM

Figure-3. Block diagram for Li-Fi data transmitter.

High brightness LED which act as a communication source.

The transmitter unit is fitted to the wall/ceiling. In the transmitter the modulated information is transmitted through LED.

Figure-4. Block diagram for Li-Fi data receiver.

Silicon photo diode which serves as a receiving element.

The receiver unit demodulates the encoded binary data and give the response in the form of voice to the person. The

receiver unit consist a photo transistor which receives the information from the LED connected to the transmitter. The

information consist of location, and whenever receiver module comes in the range of that transmitter area than

corresponding location message is send to receiver is stored in the IC APR33A3 and processed further to initiate voice to

guide the person and vibrator motor to navigate the person which can assist visually impaired people at indoor places.

Transmitter Module – generates the corresponding on-off pattern for the LEDs.

Receiver Module – has a photo diode to detect the on and off states of the LEDs. It captures this sequence and generates

the binary sequence of the received signal

Mahin et al., International Journal of Emerging Research in Management &Technology

ISSN: 2278-9359 (Volume-5, Issue-5)

© 2016, IJERMT All Rights Reserved Page | 84

The HT12E encoders are a series of CMOS LSIs for remote control system applications. They are capable of encoding

information which consists of N address bits and 12-N data bits.

TheHT12D is a device which does the reverse of an encoder, undoing the encoding so that the original information can

be retrieved. The same method used to encode is usually just reversed in order to decode.

The APR33A3 is a good standalone voice recorder or playback IC with non- volatile storage and playback capability for

340 to 680 seconds(5.6 min to 11.3 min). It canrecord and play multiple messages at random or in sequential mode.

IV. HARDWARE REQUIRED

The Mega 2560 is a microcontroller board based on the ATmega2560. It has 54 digital input/output pins (of which 15

can be used as PWM outputs), 16 analog inputs, 4 UARTs (hardware serial ports), a 16 MHz crystal oscillator, a USB

connection, a power jack, an ICSP header, and a reset button. It contains everything needed to support the

microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get

started. The Mega 2560 board is compatible with most shields designed for the Uno and the former boards Duemilanove

or Diecimila.

Figure5 General Structure of Arduino atmega2560 development board

V. CONTROL SOFTWARE

Arduino programs may be written in any programming language with a compiler that produces binary machine code.

Atmel provides a development environment for their microcontrollers, AVR Studio and the newer Atmel Studio

The Arduino project provides the Arduino integrated development environment (IDE), which is a cross-platform

application written in the programming language Java. It originated from the IDE for the languages Processing and

Wiring. It is designed to introduce programming to artists and other newcomers unfamiliar with software development. It

includes a code editor with features such as syntax highlighting, brace matching, and automatic indentation, and provides

simple one-click mechanism to compile and load programs to an Arduino board. A program written with the IDE for

Arduino is called a "sketch"

The Arduino IDE supports the languages C and C++ using special rules to organize code. The Arduino IDE supplies

a software library called Wiring from the Wiring project, which provides many common input and output procedures. A

typical Arduino C/C++ sketch consist of two functions that are compiled and linked with a program stub main () into an

executable cyclic executiveprogram:

Setup (): a function that runs once at the start of a program and that can initialize settings.

Loop (): a function called repeatedly until the board powers off.

After compiling and linking with the GNU tool chain, also included with the IDE distribution, the Arduino IDE

employs the program avrdude to convert the executable code into a text file in hexadecimal coding that is loaded into the

Arduino board by a loader program in the board's firmware.

VI. CONCLUSION

This paper will emerge as a promising technology in upcoming era by providing the navigation for visually impaired

using LI-FI.

VII. FUTURE SCOPE OF LI-FI

1] Achieving seamless interoperability with other networks in a way such that it can be operated in the outdoor

environment.

2] Driving illumination grade LEDs at high speed.

3] Overcoming the line of sight.

REFERENCES

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Mahin et al., International Journal of Emerging Research in Management &Technology

ISSN: 2278-9359 (Volume-5, Issue-5)

© 2016, IJERMT All Rights Reserved Page | 85

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