safe street crossing system org 1

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Company

LOGO

Safety Road Crossing System

For Blind People

Final Year Project Presentation

By M.H.I.M Aththanayke

IESL Part III-C

Supervisor: Mr.Dhammika Perera


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Content

Background of the projectIntroduction(Why,How)

System Design

Onsite InstallationSystem Testing

Cost Analysis

Conclusion and Further Developments

Acknowledgement

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Background of the project

If a visually impaired person chooses to walk, evencrossing the road is a big challenge, Most of ourtraffic lights are not visually-impaired friendly.

Modifying the existing traffic lights to emit audio

signals to help the visually impaired is prohibitivelyexpensive.

Solution is to device an attachment to be mounted

on the existing traffic lights to give signals tovisually impaired people will be feasible one.

Sri Lankan government come up with new idea tomake the government facilities accessible for the

disabled cause disabilities of the war heroes. 3


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Introduction

Sri Lanka's blind populationis estimated tobe between 92920 and 150000

Thousands of them are facing enormous

number of issues when they are crossingroad

Providing an safety device for above

mentioned portion of people in the societyis an vital requirement

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Why?

Commercially launched such devices arerare to find and those are so expensive

Munivo is one of the product, but it is

only for object detecting and moreexpensive as well.

Current Road Crossing system not

support to the blinds.

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How?

created a cost effective & Reliabilitydevice that will allow people with visiondisabilities to cross the street safely

The devise will not be a sign of blinds likea white cane.

The idea behind this project is to provide

more cost effective efficient and accuratedevice for the blind people that would helpthem a lot.

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System layout

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Transmitter Freq:50KHz Transmitter Freq:50KHz

Transmitter Freq:50KHzTransmitter Freq:50KHz

Transmitter Freq:25KHz

Transmitter Freq:25KHz Transmitter Freq:25KHz

Transmitter Freq:25KHz


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System Design

Safety RoadCrossing System

Transmitting UnitPower Source

Receiving UnitTransmitting Unit

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Transmitting unit Power Source

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Transmitter unit

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Continue

Transmitting unit consist of two devices basically:

RF signal Transmitter unit.

WALK signal detection unit (Using LM741)

The walk signal triggers the LDR circuit at the beginThe LDR gives 5V as its output to the

microcontroller input pins.(Two inputs from two)

Microcontroller identify which transmitter have to betrigger according to the received input signal.

Hence transmitter is transferring the RF signals inexact frequency (25kHz,50kHz)

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Walk signal

There are two types of lights that are usingin all the city signals:

Tungsten bulbs

LEDs

+5V

+5V +5V

R4 1K

R1 1M

+

-

U1

LM741

3

26

7

1 4 5R6

POT

R3 1K

R2LDR

R5

1K

Sen_SigDetect

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Continue

There are three main devices exist in tothe receiver unit:

RF signal receiver unit

Vibration motor Dry cell power supply

Receiver unit is check for the signal from

three possible directionsIt is sent out the direction for the user

when the walk signals are on

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Receiver Block Diagrame

Three antennas, Microcontroller andVibrator

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M: Middle Receiver antenna to detect the

signal coming from the Front

L: Left Receiver antenna to detect the

signal coming from the Left

R: Right Receiver antenna to detect thesignal coming from the Right

RL

Power UnitMicrocontroller

Vibrator


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State diagram for the microcontroller ofthe receiver

Receive signals from

the antennas

Check

Signals

F NF B

Vibration

010

001

100

101

011

110

111

000

Reset

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L M R0 0 0 X0 0 1 NF0 1 0 F0 1 1 B1 0 0 NF1 0 1 NF1 1 0 B1 1 1 B

Receiver antennas directions truth table


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Vibration Patterns

If only the street was safe, the motorwould vibrate in short pulses on right, left,front or both

If only the person near the safe blindcrossing system with no WALK signal itsvibrate with continuous vibration with nobuzzer

If there is no safety system nearby thenthe three directional vibrations would becontinuously vibrate with buzzer

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Vi f th t itt d


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View of the transmitters andReceiver together

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Continue

Installation image

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System testing

Checked the operating vibration patterns

Test Results

Checked the operating vibrationpatterns

Long vibration with the buzzer

Transmitter on Buzzer off & long vibration

100kHz Idle state

25kHz Vibration

50kHz Vibration

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Continue

Directivity and range of TransmitterAntennas

Tested values showed that its having

approximate 20 degree bandwidth value whentransmitting

40m maximum transmission range increases theaccuracy of the system.

Needs to use small metal disks to guide RF mainglobe and avoid Omni directional transmission.

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Transmitter frequency Checking

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Transmitter when WALK signal is on

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Transmitter when WALK signal is off

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Receiver without receiving RF signal

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Receiver receives from right side

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Cost analysis

Item Quantity Part Unit Price Price1 1000uf(25V) 2 15.00 30.002

100nf

1

1.50

1.50

3 220uf 1 8.00 8.004 0.1uf 1 1.50 1.505 15pf 2 1.00 2.006 1N4007 5 3.00 15.007 Connector 2 16.00 32.008 LED 4 2.00 8.009 Buzzer 1 45.00 45.00

10 470K 3 0.25 0.7511 1K 2 0.25 0.5012 20K Preset 2 5.00 10.0013 10K 1 0.25 0.2514 330 1 0.25 0.2515 LM317 1 20.00 20.0016 LM7805 1 18.00 18.0017 PIC16F877A 2 400.00 800.0018 4Mz 1 22.00 22.0019 1M 1 0.25 0.2520 LDR 1 19.00 19.0021 1K 3 0.25 0.7522 POT 1 5.00 5.0023 LM741 1 18.00 18.0024 40 Pin IC Base 1 20.00 20.0025 400mA Transformer 1 140.00 14026 AC Code 1 45.00 45.0027 PCB 1 450.00 450.0028 Tx Unit 1 750.00 750.0029 Rx Unit 1 750.00 750.00

30 12v 3W solar panel 1 1800.00 1800.00TOTAL 5012.75

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Conclusion and further


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Conclusion and furtherdevelopment

Restructuring the empowering unit to bemore cost efficient, using less space, andpreventing interference from other devices

Creating the Buzzer warning alarm for lowbattery state will increase the systemreliability

Adding a narrow beam antenna totransmitter for avoid Omni directionaltransmission

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Continue

Need to use advanced PCB mountingtechniques to minimize the receiverdimension such as double side surface

mountingNeed to mount the receiver unit

microprocessor on vibration free surface

for durability

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Acknowledgement

Project Supervisor:Mr.Dhammika Perera

Deputy General manager

Data & Access network operations

SLT Head Office

Colombo-02

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Q & A


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THANK YOU!

safe street crossing system org 1

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