Intelligent Blind Stick

8/16/2019 Intelligent Blind Stick

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CONTENTS PAGE NO.

1. ABSTRACT 2

2. INTRODUCTION 3

3. BACKGROUND 4

4. LITERATURE SURVEY 5

5. DESCRIPTION 6

5.1. BLOCK DIAGRAM 6

5.2. EXPLANATION 6

6.

HARDWARE REQUIREMENTS 7

6.1. MICROCONTROLLER (AT89c2051) 8

6.2. Ultrasonic Modules HC-SR04 11

6.3. 74ls153(4:1) Multiplexer 13

6.4. RF TX Rx 434 Mhz 17

6.5. Flame and Fire Detection Sensor Module 21

6.6. Water sensor module 22

7. SCHEMATIC DIAGRAM 23

7.1 DESCRIPTION 23

7.2 OPERATION EXPLANATION 25

8. SOFTWARE IMPLEMENTATION 27

8.1 SOURCE CODE 27

9. HARDWARE TESTING 35

9.1 CONTINUITY TEST 35

9.2 POWER ON TEST 36

10.

RESULTS AND DISCUSSIONS 37

11. CONCLUSION AND FUTURE SCOPE 38

10. BIBLIOGRAPHY 39


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ABSTRACT

God gifted sense of vision to the human being is an important aspect of our life. But there are

some unfortunate people who lack the ability of visualizing things. The visually impaired have to

face many challenges in their daily life. The problem gets worse when there is an obstacle in front

of them. Blind stick is an innovative stick designed for visually disabled people for improved

navigation. The paper presents a theoretical system concept to provide a smart ultrasonic aid for

blind people. The system is intended to provide overall measures – Artificial vision and object

detection. The aim of the overall system is to provide a low cost and efficient navigation aid for a

visually impaired person who gets a sense of artificial vision by providing information about the

environmental scenario of static and dynamic objects around them. Ultrasonic sensors are used to

calculate distance of the obstacles around the blind person to guide the user towards the available

path. Output is in the form of sequence of beep sound which the blind person can hear.


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INTRODUCTION

There are approximately 37 million people across the globe who are blind, over 15 million

are from India. Even for the non-visually impaired the congestion of obstacles is sometimes

problematic, it’s even worse for the visually impaired. People with visual disabilities are often

dependent on external assistance which can be provided by humans, trained dogs, or special

electronic devices as support systems for decision making. Existing devices are able to detect and

recognize objects that emerge on the floor, but a considerable risk is also includes the objects that

are at a sudden depth, or obstacles above waist level or stairs. Thus we were motivated to develop

a smart white cane to overcome these limitations. The most common tool that the blind currently

use to navigate is the standard white cane. We decided to modify and enhance the walking cane,

since blind are only able to detect objects by touch or by cane. The user sweeps the cane back and

forth in front of them. When the cane hits an object or falls off of the edge of a stair, the user then

becomes aware of the obstacle – sometimes too late. We accomplished this goal by adding

ultrasonic sensors at specific positions to the cane that provided information about the environment

to the user through audio feedback. The main component of this system is the Radio-Frequency

module which is used to find the stick if it is misplaced around.


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BACKGROUND

Vision is the most important part of human physiology as 83% of information human being gets

from the environment is via sight. The 2011 statistics by the World Health Organization (WHO) estimates

that there are 285 million people in world with visual impairment, 39 billion of which are blind and 246

with low vision [2]. The traditional and oldest mobility aids for persons with visual impairments are the

walking cane (also called white cane or stick) and guide dogs. The most important drawbacks of these aids

are necessary skills and training phase, range of motion and very little information conveyed. With the rapid

advances of modern technology, both in hardware and software front have brought potential to provide

intelligent navigation capabilities. Recently there has been a lot of Electronic Travel Aids (ETA) designed

and devised to help the blind navigate independently and safely. Also high-end technological solutions have

been introduced recently to help blind persons to navigate independently. Many blind guidance systems use

ultrasound because of its immunity to the environmental noise. Another reason why ultrasonic is popular

is that the technology is relatively inexpensive, and also ultrasound emitters and detectors are small enough

to be carried without the need for complex circuit. Blind people have used canes as mobility tools for

centuries, but it was not until after World War I that the white cane was introduced.


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LITERATURE SURVEY

Numerous attempts have been made in the society to help the blind. “Project Prakash” is ahumanitarian mission to help the blind children especially by training them to utilize their brains

to learn a set of objects around them [3]. The stick has a ping sonar sensor to sense the distant

objects. It also has a wet detector to detect the water. The micro-controller used is PIC

microcontroller. The microcontroller circuit is on the outside of the stick but is protected with a

code so its security cannot be breached. The only feedback given to the user is through the vibration

motor [4]. Three sensors are used viz. ultrasonic, pit sensor and the water sensor. Even this is a

PIC based system. The feedback given is through the vibration as well as the speaker/headphones.

There is a GPS system where-in the user has to feed his location. No information on how a blind

man would do that. Also they haven’t mentioned anything about the size and shape of their cane

and neither.


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DESCRIPTION

Explanation:

In this system the ultrasonic sensor are used to sense the obstacle (if there is any). We

have used three ultrasonic sensors at different height to detect the height of the object.

The signal is then send to microcontroller to operate a buzzer. There is one more

advantage of this system. Sometimes when the blind loose there sticks or forgot where

have they put it, they can find it by using the wireless remote. Additional features are also

added in the blind stick for safety purposes like, fire detector and water detector. The

output of the blind stick will be in the form of sound produced by a buzzer. Buzzer will

sound differently for different conditions.


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HARDWARE REQUIREMENTS

MAJOR HARDWARE COMPONENTS USED

1. MICROCONTROLLER (AT89c2051)

2. Ultrasonic Modules HC-SR04

3. 74ls153(4:1) Multiplexer

4. RF TX Rx 434 Mhz

5. Flame and Fire Detection Sensor Module

6. Water sensor module


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AT89C2051

At89c2051 is 8051 family microcontroller having only 20 pins. The purpose of using this is that it

have only 20 pins and it is very compact and use less space. As the circuit space requirements of

intelligent blind stick is very less.

Features

• Compatible with MCS®-51Products

• 2K Bytes of Reprogrammable Flash Memory – Endurance: 10,000 Write/Erase Cycles

• 2.7V to 6V Operating Range

• Fully Static Operation: 0 Hz to 24 MHz

• Two-level Program Memory Lock

• 128 x 8-bit Internal RAM

• 15 Programmable I/O Lines

• Two 16-bit Timer/Counters


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Description:

The AT89C2051 is a low-voltage, high-performance CMOS 8-bit microcomputer with 2K bytes of

Flash programmable and erasable read-only memory (PEROM). The device is manufactured using

Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard

MCS-51 instruction set. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel

AT89C2051 is a powerful microcomputer which provides a highly-flexible and cost-effective solution

to many embedded control applications. The AT89C2051 provides the following standard features: 2K

bytes of Flash, 128 bytes of RAM, 15 I/O lines, two 16-bit timer/counters, a five vector two-level

interrupt architecture, a full duplex serial port, a precision analog comparator, on-chip oscillator and

clock circuitry. In addition, the AT89C2051 is designed with static logic for operation down to zero

frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU

while allowing the RAM, timer/counters, serial port and interrupt system to continue functioning. The

power-down mode saves the RAM contents but freezes the oscillator disabling all other chip functions

until the next hardware reset.

PIN diagram And basic circuitry:


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Above Is the basic circuitry for the 89c51 microcontroller.

A crystal of 11.0592MHZ frequency is connected at X1 and X2 to provide clock pulses.

AN RC circuit is connected at RST pin to reset the microcontroller whenever the power is

turned on. It is also called power on reset.

Other connections depends on the pin requirements of the application to be designed.


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ULTRASONIC SENSOR

Ultrasonic sensors (also known as transceivers when they both send and receive) work on a

principle similar to radar or sonar which evaluate attributes of a target by interpreting the

echoes from radio or sound waves respectively. Ultrasonic sensors generate high frequency

sound waves and evaluate the echo which is received back by the sensor. Sensors calculate the

time interval between sending the signal and receiving the echo to determine the distance to an

object. This technology can be used for measuring: wind speed and direction (anemometer),

fullness of a tank and speed through air or water. For measuring speed or direction a device

uses multiple detectors and calculates the speed from the relative distances to particulates in

the air or water. To measure the amount of liquid in a tank, the sensor measures the distance

to the surface of the fluid. Further applications include: humidifiers, sonar, medical ultra

sonography, burglar alarms and non-destructive testing. Systems typically use a transducer

which generates sound waves in the ultrasonic range, above 18,000 hertz, by turning electrical

energy into sound, then upon receiving the echo turn the sound waves into electrical energy

which can be measured and displayed. The technology is limited by the shapes of surfaces and

the density or consistency of the material. For example foam on the surface of a fluid in a tank

could distort a reading.


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INTERFACING

Working:

1.

The MCU sends 10us pulse to the ultrasonic sensor module.

2. After receiving the pulse the ultrasonic transmitter sends 40 kHz ultrasound pulse train.

3. When the pulse strikes an object. It Came back to the Ultrasonic receiver and ultrasonic

coverts it to a digital pulse and interrupt the controller.

4. The MCU calculate the time taken by the Pulse to strike back. And calculate the overall

distance in cms.

In our Blind stick project we use three Ultrasonic receivers. Therefor we have to use a 3:1

multiplexer to multiplex the echo pins of the ultrasonic sensors with the MCU INT pin. 3:1

mux is not commercially available so we used 4:1 Mux IC(74LS153).


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74LS153

DUAL 4-INPUT MULTIPLEXER

The LSTTL/MSI SN54/74LS153 is a very high speed Dual 4-Input Multiplexer with common

select inputs and individual enable inputs for each section. It can select two bits of data from foursources. The two buffered outputs present data in the true (non-inverted) form. In addition to

multiplexer operation, the LS153 can generate any two functions of three variables. The

LS153 is fabricated with the Schottky barrier diode process for high speed and is completelycompatible with all Motorola TTL families.

• Multifunction Capability

• Non-Inverting Outputs

• Separate Enable for Each Multiplexer

• Input Clamp Diodes Limit High Speed Termination Effects


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FUNCTIONAL DESCRIPTION

The LS153 is a Dual 4-input Multiplexer fabricated with Low Power, Schottky barrier diode

process for high speed. It can select two bits of data from up to four sources under the control

of the common Select Inputs (S0, S1). The two 4-input multiplexer circuits have individual activeLOW Enables (Ea, Eb) which can be used to strobe the outputs independently. When

the Enables (Ea, Eb) are HIGH, the corresponding outputs (Za, Zb) are forced LOW.The LS153 is the logic implementation of a 2-pole, 4-position switch, where the position of the

switch is determined by the logic levels supplied to the two Select Inputs. The logic equations for

the outputs are shown below.

Za = Ea V (I0a V S1 V S0 + I1a V S1 V S0 + I2a V S1 V S0 +I3a V S1 V S0)

Zb = Eb V (I0b V S1 V S0 + I1b V S1 V S0 + I2b V S1 V S0 +I3b V S1 V S0)

The LS153 can be used to move data from a group of registers to a common output bus. The particular register from which the data came would be determined by the state of the Select Inputs.

A less obvious application is a function generator. The LS153 can generate two functions of threevariables.

This is useful for implementing highly irregular random logic.


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INTERFACE

The mux is used to multiplex three ultrasonic sensors with the MCU.

WORKING:Here the Trigger pins of the sensors are directly connected to the MCU. But the ECHO pins are

connected to 1X0, 1X1 and 1X2. A and B input of mux ic are also connected to the MCU. So that

MCU can select different inputs.

1. MCU selects sensor 1 by A =0, B=0

2. MCU sends trigger pulse at TRIG 1 pin.

3. The echo pulse is read by MCU at 1Y pin of the mux.

4. Similarly for sensor 2, A=1, B=0.

5. And for sensor 3, A=0, B=1.


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RF Tx-Rx 434 MHz

RF Transmitter

This simple RF transmitter, consisting of a 434MHz license-exempt Transmitter module and anencoder IC , was designed to remotely switch simple appliances on and off. The RF part consists

of a standard 434MHz transmitter module, which works at a frequency of 433.92 MHz and has a

range of about 400m according to the manufacture. The transmitter module has four pins. Apart

from “Data” and the “Vcc” pin, there is a common ground (GND) for data and supply. Last is theRF output (ANT) pin.

Pin Assignment of the 434MHz Transmitter module

Note that, for the transmission of a unique signal, an encoder is crucial. For this, I have used the

renowned encoder IC HT12E from Holtek. HT12E is capable of encoding information which

consists of N address bits and 12N data bits. Each address/ data input can be set to one of the twologic states. The programmed addresses/data are transmitted together with the header bits via an

RF transmission medium upon receipt of a trigger signal. Solder bridges TJ1 and TJ2 are used to

set the address and data bits.

The current consumption with a supply voltage of near 5.4V is about 10 mA. Since the current

consumption is very little,the power can also be provided by standard button cells. Recommended

antenna length is 17 cm for 433.92 MHz, and a stiff wire can be used as the antenna. Rememberto mount the antenna (aerial) as close as possible to pin 4 (ANT) of the transmitter module

http://www.electroschematics.com/wp-content/uploads/2013/04/Pin-Assignment-of-the-434MHz-Transmitter-module.pnghttp://www.electroschematics.com/wp-content/uploads/2013/04/434MHz-transmitter-module.png


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RF Transmitter – Schematic Diagram

RF Receiver

This circuit complements the RF transmitter built aorund the small 434MHz transmitter module.

The receiver picks up the transmitted signals using the 434Mhz receiver module. This integratedRF receiver module has been tuned to a frequency of 433.92MHz,exactly same as for the RF

transmitter.

434MHz receiver module

The miniature 434MHz RF receiver module receives On-Off Keyed (OOK) modulation signal and

demodulates it to digital signal for the next decoder stage. Local oscillator is made of Phase Locked

Loop (PLL) structure. Technically, this is an Amplitude Shift Keying (ASK) receiver module based on a single-conversion, super-heterodyne receiver architecture and incorporates an entire

http://www.electroschematics.com/wp-content/uploads/2013/04/434MHz-Receiver-module.pnghttp://www.electroschematics.com/wp-content/uploads/2013/04/RF-Transmitter-Schematic-Diagram.png


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Phase-Locked Loop (PLL) for precise local oscillator (LO) generation. It can use in OOK / HCS /

PWM modulation signal and demodulate to digital signal.

The receiver module has eight (4+4) pins. Apart from three “ground (GND) ” and two “Vcc” pins,

there are two pins (one for Digital Data & other for Linear Data) for data output. Last is the RF

input (ANT) pin.

Pin Assignment of the 434MHz Receiver module

Pin Connections

1 Antenna

2 Ground

3 Ground 4 Vcc

5 Vcc

6 Linear Data (Normally NOT used)

7 Digital Data (Normally Used)

8 Ground

The “coded” signal transmitted by the transmitter is processed at the receiver side by th e decoderIC HT12F from Holtek. VR1 and R1 are used to tweak the oscillator frequency of the decoder to

that of the transmitter. Any possible variations due to component tolerences and/or a differentsupply voltage can be compensated by this arrangement. HT12F is capable of decoding

informations that consist of N bits of address and 12N bits of data. HT12F decoder IC receives

serial addresses and data from the HT12E encoder that are transmitted by the RF transmittermodule. HT12D compare the serial input data three times continuously with the local addresses.

http://www.electroschematics.com/wp-content/uploads/2013/04/Pin-Assignment-of-the-434MHz-Receiver-module.png


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If no error or unmatched codes are found, the input data codes are decoded and then transferred to

the output pins. The “Valid Transmission” (VT) pin also goes high to indicate a valid transmission.

For proper operation, a pair of HT12E/HT12F ICs with the same number of addresses and data

format should be chosen. The data bits are set up using solder bridges RJ1 and RJ2. Output of the

decoder is brought out on a pinheader K1 , making the logical signal available to circuits that needit. This output is also fed to the relay driver transitor T1. The RF Receiver circuit can be powered

from a standard 5VDC supply. Just as for the RF Transmiitter, the aerial (17 cm for 433.92 MHz)

has to be mounted as close as possible to the RF IN (ANT) pin of the 434MHz RF receiver module.

RF Receiver – Schematic Diagram

http://www.electroschematics.com/wp-content/uploads/2013/04/RF-Receiver-Schematic-Diagram.png


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Flame and Fire Detection Sensor Module

Description

The Fire sensor is used to detect fire flames . The module makes use of Fire sensor and

comparator to detect fire up to a range of 1 meters.

Allows your robot to detect flames from up to 1M

Typical Maximum Range: 1 meter

Calibration preset for range adjustment

Indicator LED with easy interface connector

Input Voltage: 3.3V to 5V

Features:

Can detect the flame or the wavelength at 760nm to 1100nm range of the light source,

The test flame lighters distance of 80cm, The larger the flame, the greater the distance test

The detection angle of approx 60 degrees, sensitive to the flame spectrum

Sensitivity adjustable (Refer picture for blue digital potentiometer)

The comparator output signal clean waveform is good, driving ability, than 15mA

With adjustable precision potentiometer for sensitivity adjustment

With LED indication

Operating Voltage: 3.3V-5V

Output in the form: DO digital switching outputs (0 and 1) and AO analog voltage output Fixed bolt holes for easy installation

Small PCB size: 3.2cmx1.4cm

Using a wide voltage LM393 comparator


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Water Sensor Module

Description

This is simple and small portable water level/water droplet identification, detection sensor water

that have high cost performance. Complete water yield and analog conversion, the output valueapply to your custom function. It is low power consumption and high sensitivity. It can make better

performance with Arduino 328 controller and sensor relay shield.

Water Sensor water level sensor is an easy-to-use, cost-effective high level/drop recognition

sensor, which is obtained by having a series of parallel wires exposed traces measured

droplets/water volume in order to determine the water level. Easy to complete water to analog

signal conversion and output analog values can be directly read Arduino development board to

achieve the level alarm effect.

Key Features

.Brand new Water Level Alarm Sensor Module Liquid Level Sensor Circuit Board

.This sensor module can estimate the water level through a series of exposed parallel

conductor line marks measuring the water droplets and capacity

.Easily convert water to analog signal, the output analog signal can be read directly on thearduino board to achieve the effect of water level alarm

.The surface have gone through plating processing to enhance the electrical conductivity

and corrosion resistance

.Simple circuit and easy to use and high cost performance

Specifications

Working Voltage: DC 3-5V

Working Current:


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SCHEMATIC DIAGRAM

SCHEMATIC EXPLANATION

STANDARD CONNECTIONS TO 8051 SERIES MICRO

CONTROLLER

ATMEL series of 8051 family of micro controllers need certain standard connections. The

actual number of the Microcontroller could be “89C51” , “89C52”, “89S51”, “89S52”, and as

regards to 20 pin configuration a number of “89C2051”. The 4 set of I/O ports are used based on

the project requirement. Every microcontroller requires a timing reference for its internal program

execution therefore an oscillator needs to be functional with a desired frequency to obtain the timing

reference as t =1/f.


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A crystal ranging from 2 to 20 MHz is required to be used at its pin number 18 and 19 for

the internal oscillator. It may be noted here the crystal is not to be understood as crystal oscillator

It is just a crystal, while connected to the appropriate pin of the microcontroller it results in

oscillator function inside the microcontroller. Typically 11.0592 MHz crystal is used in general

for most of the circuits using 8051 series microcontroller. Two small value ceramic capacitors of

33pF each is used as a standard connection for the crystal as shown in the circuit diagram.

RESET

Pin no 1 is provided with an resset arrangement by a combination of an electrolytic

capacitor and a register forming RC time constant. At the time of switch on, the capacitor gets

charged, and it behaves as a full short circuit from the positive to the pin number 1. After the

capacitor gets fully charged the current stops flowing and pin number 1 goes low which is pulled

down by a 10k resistor to the ground. This arrangement of reset at pin 1 going high initially and

then to logic 0 i.e., low helps the program execution to start from the beginning. In absence of this

the program execution could have taken place arbitrarily anywhere from the program cycle. A

pushbutton switch is connected across the capacitor so that at any given time as desired it can be

pressed such that it discharges the capacitor and while released the capacitor starts charging again

and then pin number 1 goes to high and then back to low, to enable the program execution from

the beginning. This operation of high to low of the reset pin takes place in fraction of a second as

decided by the time constant R and C.

For example: A 10µF capacitor and a 10kΩ resistor would render a 100ms time to pin number 1

from logic high to low, there after the pin number 1 remains low.


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BRIEF DESCRIPTION OF TRANSISOR ACTING AS SWITCH

An NPN transistor is "on" when its base is pulled high relative to the emitter. The arrow in the

NPN transistor symbol is on the emitter leg and points in the direction of the conventional current

flow when the device is in forward active mode. Whenever base is high, then current starts flowing

through base and emitter and after that only current will pass from collector to emitter.

OPERATION EXPLANATION

Microcontroller and connections:

The microcontroller used is AT89C2051. The 20th pin of the IC is given a 5v power supply.

Pins 4 & 5 of the IC are used to connect crystal to the microcontroller. Pin 1 of the IC is the reset

pin which is connected to a mechanical switch. The trigger pins of the ultrasonic sensors are

connected to P3.5,4 and 3. The multiplexed echo pin of the sensors is connected to P3.2 which is

INT pin of MCU. Water sensor and the buzzer connected to P1.7 and 6 respectively.


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CIRCUIT WORKING

As it is an embedded project, the circuit compilations are reduced with an efficient

program. In the circuit diagram of our purposed design when the blind person presses the switch

on the stick. The circuit gets the power supply and the MCU activates sensors by giving appropriate

signals to the select pins of the multiplexer IC and triggering the sensors. After getting trigger

pulse the selected ultrasonic sensor transmits a ultrasound of 40k and its gets back after striking

the object. The MCU calculates the time and distance and stores it. After that MCU selects the

second sensors and calculate its distance also. Same will be done for sensor 3.

After it gets all the distance of the sensors. It compares that distance with the already

stored value which is 60cm. If the distance calculated by the topmost sensor is less than 60cm. The

buzzer will beep very fast after 200ms. Otherwise if the middle sensors distance is less than 60 cm

then buzzer beep will be slow at 400ms interval. For lowest sensor the buzzer beep will be 1sec.

This variation can be used by the blind person to approximate the height of the object.

If the water sensor detects water at the bottom of the stick. It will give high signal to the

controller. And controller is programmed to beeps the sound 3 times faster and give it a delay.

Fire sensor is directly connected to buzzer. Whenever Fire is detected it triggers the buzzer.The buzzer in this case continuously beeps.

Buzzer is also directly connected to RF receiver circuit. Whenever the blind person have

to finds his stick. He will simply have to press a micro switch on his remote, which gives input the

RF encoder and transmitted by the transmitter. The signal gets received by the rf receiver and

decoded by the decoder and its output triggers the buzzer. The buzzer gets turned on and it will

help the blind to find his stick.


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SOFTWARE IMPLEMENTATION

SOURCE CODE

#include

#include

#include

#define delay_10us() _nop_();_nop_();_nop_();_nop_(); _nop_();_nop_();_nop_();_nop_()

sbit wat = P1^2;

sbit TRIG1 = P3^5;

sbit TRIG2 = P3^4;

sbit TRIG3 = P3^3;

sbit SEL0 = P1^0;

sbit SEL1 = P3^7;

sbit buzzer = P1^7;

unsigned int T0_ISR_count = 0;

unsigned long high_time_us; // 32 bit variable, stores pulse time in uS

unsigned long distance_cm1; // 32 bit variable, Distance Value in Centimeter




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unsigned long distance_in; // 32 bit variable, Distance Value in Inches

void calculate();

void delay_ms(int);

unsigned int i;

void serial_init() {

/*--------------------------------------

Set serial port for 9600 baud at

11.0592 MHz. Note that we use Timer 1

for the baud rate generator.

--------------------------------------*/

SCON = 0x50;

TMOD |= 0x20;

TH1 = 0xFA;

TR1 = 1;

TI = 1;

PCON |= 0x80;

}

void T0_ISR (void) interrupt 1

{


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T0_ISR_count++;

TF0 = 0;

}

void main (void)

{

buzzer = 0;

TRIG1 = TRIG2 = TRIG3 = 0;

//serial_init(); // Init serial port at 9600

// printf ("\nUltrasonic Distance Sensor\n");

ET0 = 1;

EA = 1;

TMOD = (TMOD & 0xF0) | 0x09;

while (1)

{

SEL1=0;SEL0=0;

TRIG1 = 1;

delay_10us();

TRIG1 = 0;

calculate();


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distance_cm1=high_time_us/58;

delay_ms(50);

SEL1=0;SEL0=1;

TRIG2 = 1;

delay_10us();

TRIG2 = 0;

calculate();

distance_cm2=high_time_us/58;

delay_ms(50);

SEL1=1;SEL0=0;

TRIG3 = 1;

delay_10us();

TRIG3 = 0;

calculate();

distance_c0m3=high_time_us/58;

delay_ms(50);

/*if(distance_cm1 > 0 && distance_cm1 < 500) // check valid range then only print

printf("Distance1: %6lu cm\n", distance_cm1);


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if(distance_cm2 > 0 && distance_cm2 < 500) // check valid range then only print

printf("Distance2: %6lu cm\n", distance_cm2);

if(distance_cm3 > 0 && distance_cm3 < 500) // check valid range then only print

0 printf("Distance3: %6lu cm\n", distance_cm3);*/

if(wat == 0)

{

buzzer=1;

delay_ms(50);

buzzer=0;

delay_ms(50);

buzzer=1;

delay_ms(50);

buzzer=0;

delay_ms(50);

buzzer=1;

delay_ms(50);

buzzer=0;

delay_ms(50);

}

else if(distance_cm3


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{

buzzer=1;

delay_ms(200);

buzzer=0;

delay_ms(50);

}

else if(distance_cm2 < 60)

{

buzzer=1;

delay_ms(400);

buzzer=0;

delay_ms(250);

}

else if(distance_cm1 < 60)

{

buzzer=1;

delay_ms(1000);

buzzer=0;

delay_ms(850);

}

else


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buzzer=0;

}

}

void calculate()

{

T0_ISR_count = 0;

TH0 = 0;

TL0 = 0;

TR0 = 1;

i=0;

while (!INT0)

{

i++;

if(i>20000)

break;

}

i=0;

while (INT0)

{

i++;


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if(i>20000)

break;

}

high_time_us = (unsigned long)((TH0


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HARDWARE TESTING

CONTINUITY TEST:

In electronics, a continuity test is the checking of an electric circuit to see if current flows

(that it is in fact a complete circuit). A continuity test is performed by placing a small voltage

(wired in series with an LED or noise-producing component such as a piezoelectric speaker) across

the chosen path. If electron flow is inhibited by broken conductors, damaged components, or

excessive resistance, the circuit is "open".

Devices that can be used to perform continuity tests include multi meters which measure

current and specialized continuity testers which are cheaper, more basic devices, generally with a

simple light bulb that lights up when current flows.

An important application is the continuity test of a bundle of wires so as to find the two

ends belonging to a particular one of these wires; there will be a negligible resistance between the

"right" ends, and only between the "right" ends.

This test is the performed just after the hardware soldering and configuration has beencompleted. This test aims at finding any electrical open paths in the circuit after the soldering.

Many a times, the electrical continuity in the circuit is lost due to improper soldering, wrong and

rough handling of the PCB, improper usage of the soldering iron, component failures and presence

of bugs in the circuit diagram. We use a multi meter to perform this test. We keep the multi meter

in buzzer mode and connect the ground terminal of the multi meter to the ground. We connect both

the terminals across the path that needs to be checked. If there is continuation then you will hear

the beep sound.


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POWER ON TEST:

This test is performed to check whether the voltage at different terminals is according to

the requirement or not. We take a multi meter and put it in voltage mode. Remember that this test

is performed without microcontroller. Firstly, we check the output of the transformer, whether we

get the required 12 v AC voltage.

Then we apply this voltage to the power supply circuit. Note that we do this test without

microcontroller because if there is any excessive voltage, this may lead to damaging the controller.

We check for the input to the voltage regulator i.e., are we getting an input of 12v and an output

of 5v. This 5v output is given to the microcontrollers’ 40 th pin.

Hence we check for the voltage level at 40

th

pin. Similarly, we check for the other terminalsfor the required voltage. In this way we can assure that the voltage at all the terminals is as per the

requirement.


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RESULTS AND DISCUSSIONS

We validated the effectiveness and advantages of our proposed methodology by doing software

testing. Each module of the program was verified with various test cases. The device was

programmed in such a way that it uses the available memory of AT89C2051 efficiently. The

prototype was well designed to implement all the software modules and tested with all possible

cases.

The prototype suffers from some limitations as well. It is built using 8051 FAMILY MCU which

has limited memory, and therefore, there is a limitation on maximum number of SENSORS that it

can use.


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CONCLUSION AND FUTURE SCOPE

The proposed project undertakes a viable solution to the blind persons by providing artificial vision

on objects and to determine their way. Also the purposed design provides safety to the blind person

by alerting the fire and water.

The idea can be further modified by using a voice playback module which alerts the blind person

by giving speech notifications. The blind stick can also be equipped with GPS module for partially

deaf people.


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BIBLIOGRAPHY

TEXT BOOKS REFERED:

1. “The 8051 Microcontroller and Embedded systems” by Muhammad Ali Mazidi and Janice

Gillispie Mazidi , Pearson Education.

2. ATMEL 89C2051 Data Sheets.

THE INTERNET SOURCES

http://www.atmel.com/images/doc0368.pdf

http://www.elechouse.com/elechouse/index.php?main_page=product_info&cPath=&products_id=2233

http://www.electroschematics.com/8712/rf-based-wireless-remote-control-system

https://electrosome.com/wp-content/uploads/2014/08/Working-of-HC-SR04-Ultrasonic-Sensor.jpg

REFERENCES[1] Rohit Sheth “Smart White Cane- an Elegant and Economic Walking Aid”

[2] www.who.int/mediacentre/factsheets/fs282/en/

[3] “Project Prakash” http://web.mit.edu/bcs/sinha/prakash.html

[4] Mohammad Hazzaz Mahmud, “Smart walking stick - an electronic approach to assist visually

disabled persons” “http://www.ijser.org/researchpa per%5CSmart-walking-stick-an-electronic-

approach-to-assist- visually-disabled- persons.pdf”.
http://www.atmel.com/images/doc0368.pdfhttp://www.atmel.com/images/doc0368.pdfhttp://www.elechouse.com/elechouse/index.php?main_page=product_info&cPath=&products_id=2233http://www.elechouse.com/elechouse/index.php?main_page=product_info&cPath=&products_id=2233http://www.electroschematics.com/8712/rf-based-wireless-remote-control-systemhttp://www.electroschematics.com/8712/rf-based-wireless-remote-control-systemhttps://electrosome.com/wp-content/uploads/2014/08/Working-of-HC-SR04-Ultrasonic-Sensor.jpghttps://electrosome.com/wp-content/uploads/2014/08/Working-of-HC-SR04-Ultrasonic-Sensor.jpghttps://electrosome.com/wp-content/uploads/2014/08/Working-of-HC-SR04-Ultrasonic-Sensor.jpghttp://www.electroschematics.com/8712/rf-based-wireless-remote-control-systemhttp://www.elechouse.com/elechouse/index.php?main_page=product_info&cPath=&products_id=2233http://www.atmel.com/images/doc0368.pdf

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Intelligent Blind Stick