G.Joselin Retna Kumar, Purva Saxena, Uday Kumar


Retna Kumar, Purva Saxena, Uday Kumar Mamidala, Anupam Pammi

Department of Electronics and Instrumentation Engineering

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SRM Institute of Science and Technology




People with disabilities who use visual aids like hearing aid, blind stick for
obstacle detection while walking etc. are often discriminated in the society as
they are handicapped. The main focus of this paper is to create an assistive
device for the visually impaired as well as deaf to make them socially
acceptable without showing their disability to the society by using visible
aid. It is incorporated with features like GPS location update, GSM based
messaging system to notify relatives of the location of the user in case of
emergency situations and voice recognition based home automation. It uses ultrasonic
sensors to detect obstacles and vibration motors to notify the user about the
obstacle thus eliminating the use of external device for communication.


Keywords— visually impaired, deaf, ultrasonic
sensors, vibrating motors, GPS, GSM, voice recognition based home automation.


I.     Introduction

Navigation for
visually impaired and deaf is a big problem. “India currently has around 12 million blind people against 39 million
globally” which makes India home to one-third of the world’s blind 1. Over 21 million people in India are
suffering from one or the other kind of disability out of which the people with
vision disability accounts to 48.5% and having hearing disability accounts to
5.8% according to 2001 census data. In the past
decades, many devices have been made for the blind to assist them which are
available in various forms like portable, wireless, wearable etc. Features like
RFID, GPS technology are the most recent technologies that are used these days.
But the problem with RFID technology for navigation is that it can be used only
for a defined known area which requires complex setup. Also, internet
connection is required at all times for GPS technology when used for navigation
purpose. With the development of modern technology many different types of
navigational aids have been developed to assist the blind people commonly known
as electronic travel aid 2. People with impaired vision mostly use cane or guide
dogs for navigation. Smart cane is one of the
most common assisting tool for the visually impaired people 3. The main
advantage is low cost. But still
these systems are of limited assistance which are not hands-free. Also, it can
be used only for recognizing above the knee obstacles. 4 Other smart aids include
Effective Fast Response Smart Stick for Blind People” 15, which is a stick
incorporated with infrared sensor to detect the objects present around them. The
major disadvantage of this proposed method is that it can operate only during
day time. Another proposed aid is The NavBelt which is a navigational aid and consists of a portable
computer, ultrasonic sensors and stereophonic headphones in which the computer
applies navigation and obstacle avoidance technologies that were developed
originally for mobile robots4.The ” 2D vibration array as an
assistive device for visually impaired”, proposed methodology deals with implementation of a wearable 2D
vibration array (miniature vibrators) connected to a portable computer and two
miniature cameras (attached to a pair of dark glasses), a microphone and an ear
speaker. The cameras capture images from the surrounding environment and after
appropriate processing 3D representations are created. These 3D space
representations are projected on the 2D array attached to the person’s chest
vibrates in various levels corresponding to the distances of the surrounding obstacles
5. According to the voice operated outdoor navigation system for
visually impaired persons describes a Navigation system that makes use of GPS (the
Global Positioning System), voice and ultrasonic sensor for obstacle detection.
14 which uses voice commands to guide the bind person through an unknown
environment. This model cannot be used for people having hearing impairment and
is possible only where internet connection is available at all times.


the major objective of the proposed idea is to create a
hands-free device incorporated with MaxSonar –ultrasonic obstacle detection sensors
which detect the obstacles in front, top, bottom, pit holes and sideways thus
providing maximum coverage area for the user. 
When obstacles are detected, the MaxSonar sensors located at shoulders
and side of the smart bag generates analog /PWM signals which are received by
microcontroller and are processed using algorithm to analyze the obstacle
position and produce specific vibration patterns to the vibration motors placed
on the back of the bag.


The bag also includes a panic safety
button which when pressed during emergency situations, sends the location of
the user to his relative using GPS and GSM module. 13


By using this
normal looking smart bag, the blind person can easily navigate his path with
safety. With the smart features incorporated in this bag, it makes the person
more self-reliant and independent. It will make their life simpler and they can
live with confidence and dignity without showing their disability by using
visible aids.


II.    proposed methodology

  The backpack is designed in such
a way that the ultrasonic sensors detects the obstacles and the blind person is
notified about the obstacle using vibrators which is in contact with the body
of the person. The Ultra Sonic sensors-MB1010 and MB1000 used in detecting the
objects are placed on the straps of the bag which detects the obstacles in the
front, top level hanging objects, steps and also detects man holes on the ground
11. Along with these it also detects obstacles approaching from left and
right side of the person while crossing roads. After detecting these obstacles,
it is conveyed to the user using vibration patterns.


These vibrating
motors are placed on the back of the bag which vibrate and is sensed by the
back of the person. These vibrators are located on different positions which
conveys the direction of obstacles. All the sensors are placed at different
angles to cover the maximum range around the blind person. This backpack is
designed with a combination of GPS tracking device which sends location of the
person via SMS using a GSM module and a voice recognition system for home
automation making it secure and user friendly. 13



As normal backpacks are used hence the possibility to show the
disability of the person is eliminated.

It is a hands-free device.

Increased coverage area over existing models.

It has
smart features like voice recognition using home automation, location update
text to relatives in panic situations.

It has
obstacle detection range of 5m.


III.   System design

The proposed model is shown in Fig.1
describes the alignment of seven proximity sensors on shoulder straps of the
bag. The seven vibration motors are placed on the back of the bag which touches
the user back which helps in feeling the vibration patterns produced by the vibration motors for different scenarios of
obstacle detection. Fig.2.  describes the position of the various
components in the bag which includes-power supply, power distribution board,
GPS module, GSM module and microcontroller in the circuit board case placed
inside the bag. Fig.3.  describes the
Alignment of sensors with angles on the bag. The sensors are placed at various
angles to cover maximum coverage area for increased safety for the user. The
Fig.4.  shows the alignment of the
Vibration motors on the bag to notify the user of the different position of the
obstacles. The vibration motors 6 and 7, according to the Fig.4 are placed on
the adjusters which comes around the user’s waist.


The MCU, GPS, GSM modules, power
distribution board are placed inside the bag in a rectangular case holding all
the hardware components including battery. A panic safety button is placed on
one of the strap helps user to send location updates to his/her family member
through SMS.








Fig.1. -3D representation of
smart bag using solid works


Fig.2.  Position of
the components in the bag



Fig.3.  Alignment of sensors
on the bag


Fig.4.  Alignment
Vibration motors on the bag

IV.   Block Diagram

The block diagram of proposed methodology
is shown in Fig.5 which describes the power distribution from the supply to MCU,
input signals from ultra-sonic sensors, and output signals from the MCU to
vibration motors. The Panic safety button which when pressed powers ON GSM and
GPS module and sends location of the user to the prefixed number via SMS. The
microphone receives commands from user which is decoded by MCU and sends the
command to home automation setup via SMS. This SMS is read by home automation
circuit and activate relays to switch ON/OFF of the devices.


The home automation circuit includes a GSM
SIM 900A module connected to a MCU and relay switches to control the devices
remotely using voice command by the user.



Fig.5 Block diagram of proposed system.



V.    System operatrion

When the system is turned ON,
the ultrasonic sensors MB1010 and MB1000 send ultrasonic waves and find the
obstacles situated at the top, front, down, left and right sides of the user
11. When the obstacle is detected, the vibration motors generate specific
pattern to notify the user. In case of emergency situations, provision for
panic safety button is there which when pressed sends the GPS location via SMS
to the relatives by using GSM technology. For indoor purpose, voice recognition
system is incorporated in the bag for home automation for the ease of the user.  The working flow of system is described in

Fig.6 Working flow of system.


VI.   Obstacle detection

Fig.7 Describes the direction of ultrasonic
waves while detecting people in front direction when ultrasonic sensors are
placed in the straps of the bag.



Front detection of obstacles

Fig.8 Describes the direction of ultrasonic
waves while detecting manhole in front direction when ultrasonic sensors are
tilted with and angle 30 degree and placed on the straps of the bag.


Fig.8- Front man hole detection


manhole detection, when the sensor 5 ranges above the threshold distance value,
the vibration motor 5 vibrates to notify the user about the man hole or trench
in front of the user.

Table 1
– describes the various vibration patterns generated by MCU for different
obstacle position.


 Table 1: Mapping of sensors to Vibration


Obstacle location

 Corresponding vibrating motor

Sensor 1

For front hanging objects

Vibration motor 1

Sensor 2

Front Right

Vibration motor 2

Sensor 3


Vibration motor 3

Sensor 4

Front left

Vibration motor 4

Sensor 5

Front manhole

Vibration motor 5

Sensor 6

Left Side
 (Side detection)

Vibration motor 6

Sensor 7

Right Side
(Side detection)

Vibration motor 7


Table 2
– describes the various vibration patterns generated by MCU for different
obstacle position.


 Table 2: Vibration pattern


Response of the vibrating motor

Obstacle is
static or in motion and user is in motion and both are moving towards each

pattern is as follows: -3seconds ON 1 second OFF.

and user both are static

Idle mode
condition: manual  control is used to
switch of the system to reduce power consumption.

Obstacle is
static and is present at one or both sides of the user who is in motion(example-
wall on the side of the user) .

If obstacle
is present at the same distance for more than 30 seconds vibration pattern is
as follows: -2seconds ON 2 seconds OFF

and user both are in motion (example-when moving in crowded area)

value decreases to 30cm for all sensors by the remote control.


Each sensor is mapped with a vibrating
motor according to the Table.1. Thus, when the obstacle is detected by a
specific sensor, the vibration motor mapped to that sensor will vibrate
according to this table as per the different scenarios specified in Table.2.
The microcontroller is coded based on the various scenarios for the ease of the






VII. System Hardware Description


The following hardware components are used in
the proposed system design.

A. Proximity

The proposed model
uses proximity sensors like MB1000 which has wide beam, works at 20Hz reading
rate operating at 2.5-5.5V with low 20mA average current requirement which is
great for people detection applications  and MB1010 for long and narrow range obstacle detection 6 whereas the other
proximity sensor MB1010 has narrow long beam works at 20Hz reading rate
operating at 2.5-5.5V with low 20mA average current requirement which is great
for long obstacle detection application with a maximum range of 254 inches 7.


B. Micro control Unit

The proposed model
uses MSP432P401R MCU which is a low power, high
performance microcontroller which includes a 48MHz ARM Cortex-M4F,
80uA/MHz active power and 660nA RTC operation with 16-bit performance and
AES256 accelerator 8.  This
microcontroller has a memory of 256KB flash and 64KB RAM with 4×16-bit and
2×32-bit timers.

C. GSM Modem Sim900

GSM modem is
a device which is used for the communication of the user with the display
board. It has slots for holding SIM card and RS-232 port for connection with
computer and other devices. It works with frequencies 850/ 900/ 1800/ 1900 MHz
the baud rate can be from 9600-115200. With the AT command, it is suitable for
SMS transfer, Voice as well as DATA transfer application in M2M interface.   The sending of SMS and receiving the SMS can
by controlled by the AT commands from the microcontroller 9.

The Modem
Specifications are:

• Quad-Band
GSM/GPRS 850/ 900/ 1800/ 1900 MHz

• RS232
interface for direct communication

Configurable baud rate

• SIM Card

• Built in
Network Status LED

• Input
Voltage: 5V-12V DC

• SMS:

1. Point to
point MO and MT

2. SMS cell

3. Text and
PDU mode


D. GPS Module

The proposed
system uses NEO-6 module series is a family of stand-alone GPS receivers which
has high performance u-blox 6 positioning engine. They are flexible and cost-effective
receivers which offers numerous connectivity in a miniature 16×12.2×2.4mm
package. The compact architecture has power and memory options which make NEO-6
modules ideal for battery operated mobile devices at cheap cost. The 50-channel
u-blox 6 positioning engine boasts a Time-To-First-Fix (TTFF) of under 1 second
10. This innovative design and technology suppresses jamming sources as-well-as
mitigates multipath effects, giving NEO-6 GPS receivers excellent navigation
performance even in the most challenging

E. Vibration motor

Flat 1027 mobile vibration motors are used to
generate vibrations which is used to notify the user about the obstacle
present. This vibration motor has a voltage range of DC 2.5-4 V with motor
diameter of 10 mm and minimum rated rotating speed of
9000rpm, which is
placed at the backside of the bag at different locations according to Fig.4 are
in contact with the user. 12


Future scope

This navigation aid can be improvised to
3600 obstacles detection surrounding the user.
Implementing Image scanning technology an object can be scanned analyzed and
also distance of the user from that obstacles can be detected using high end processors.
This navigation aid further can be improvised to give step by step directions
updates using google maps for user if he wants to walk to a destination from a
source location.


Targeting 12 million blind people in
India and 39 Million blind people across the globe 1 and applicable for all
genders and age groups (7years above) this novel navigation system is designed
and implemented with smart features for the blind user to live a life with
security and independency. A MSP432P401R microcontroller was used to develop
the smart obstacle detection system and notify the user through vibrating
patterns in different scenarios. The primary objective of this proposed system
was to create a hands-free device with features like emergency location updates
to relatives and voice recognition based home automation.





2 Yen, D H
,”Currently Available Electronic Travel Aids for the Blind”, September 21,



3Ifukube,T., Sasaki,T., Peng,C, “A
Blind Mobility Aid After Echolocation of Bats”, in Proc. IEEE Transaction on Biomedical Engineering,
vol.38, no.5, pp.461-466, May,1991.


4 S. Shoval, J. Borenstein, and Y. Koren, “The
NavBelt- A computerized travel aid for the blind based on mobile robotics
technology,” in Proc. IEEE Transactions on Biomedical Engineering,
vol. 45, no 11, pp. 1376-1386,1998.


Dakopoulos, S. K. Boddhu, and N. Bourbakis, “A 2D vibration array as an
assistive device for visually impaired,” in Proc.  IEEE
Int. Conf.Bioinf. Bioeng., Boston, MA, vol. 1, pp. 930–937. Oct. 14–17, 2007.


6 MB1000
ultrasonic sensor specifications as per Maxbotix.



7 MB1010
ultrasonic sensor specifications as per Maxbotix.



8 MSP-EXP432P401R
specifications as per Ti.com



9 Sim 900A GSM module specification as per









13 Lokesh.A1, Manjunath.T2, Karthik3,
Srisail4, Kiran.M5,

“Electronic Stick Along With
Android Smartphone’s To the Aid of Blindly Disabled Individuals”,
Int. J. IJRTER,vol. 02, Issue 05;
ISSN: 2455-1457, May,2016.


14Somnath koley1, Ravi mishra2,”voice operated outdoor navigation system for
visually impaired persons”,
Int. J. International
Journal of Engineering Trends and Technology, vol. 03, Issue 02-


15 Ayat Nada, Samia Mashelly, Mahmoud A. Fakhr, and Ahmed
F. Seddik ,”Effective
Fast Response Smart Stick for Blind People”, in Proc.
International Conference on Advances in
Bio-Informatics and Environmental Engineering-ICABEE,2015.



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