project report on dynamic traffic system

7/30/2019 Project Report on Dynamic Traffic System

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DENSITY BASED TRAFFIC CONTROL

SYSTEM

DARA MANOJ

Department of Electrical and Electronics Engineering

MAHATMA GANDHI INSTITUTE OF TECHNOLOGY

(Affiliated to Jawaharlal Nehru Technological University, Hyderabad, A.P.)

Chaitanya Bharathi P.O., Gandipet, Hyderabad 500 075

2012-2013


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DENSITY BASED TRAFFIC CONTROL SYSTEM

INDUSTRY ORIENTED MINI PROJECT REPORT

SUBMITTED IN PARTIAL FULFILLMENT

OF THE REQUIREMENTS FOR THE DEGREE OF

BACHELOR OF TECHNOLOGY

IN

ELECTRICAL AND ELECTRONICS ENGINEERING

BY

DARA MANOJ(09261A0215)

Department of Electrical and Electronics Engineering



Chaitanya Bharathi P.O., Gandipet, Hyderabad 500 075

2012-2013


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Chaitanya Bharathi P.O., Gandipet, Hyderabad-500 075Department of Electrical and Electronics Engineering

CERTIFICATE

This is to certify that the mini project work entitledDENSITY BASED TRAFFIC

CONTROL SYSTEM is being submitted by DARA MANOJ bearing Roll

No.09261A0215 in partial fulfillment for the award of Degree ofBACHELOR OF

TECHNOLOGY in ELECTRICAL & ELCTRONICS ENGINEERING by the

Jawaharlal Nehru Technological University, Hyderabad during the academic year 2012-

13.

The results embodied in this report have not been submitted by the student to any

other University or Institution for the award of any degree or diploma.

Mini Project Supervisor

Dr. P Chandra Sekhar

Associate professor

EEE Department

Head Of The Department

Dr. P Ram Kishore Kumar Redd

Associate professor & Head

EEE Department


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CERTIFICATE OF THE ORGANISATION


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ACKNOWLEDGEMENT

I express my deep sense of gratitude to my beloved Principal Dr. G Chandra

Mohan Reddy, for the valuable guidance and for permitting us to carry out this project.

I express my deep sense of gratitude to my beloved professor Dr. P.Ram

Kishore Kumar Reddy, Professor and Head, Department of Electrical & Electronics

Engineering for the valuable guidance and suggestions, keen interest and through

encouragement extended throughout period of project work.

I express my deep sense of gratitude to my beloved project guide

Mr.V.Ramakrishna for the valuable guidance and suggestions, keen interest and

through encouragement extended throughout period of project work.

I take immense pleasure to express my deep sense of gratitude to our beloved

Guide Dr.P.Chandrasekhar,Associate professor in Electrical and Electronics

Engineering, for his valuable suggestions and rare insights, for constant source of

encouragement and inspiration through out my project work.

I express my thanks to all those who contributed for the successful

completion of my project work.

With gratitude,

DARA MANOJ ________________


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CONTENTS

CHAPTER NO. TITLE PAGENO

ABSTRACT i

LIST OF FIGURES ii

LIST OF TABLES iii

1 INTRODUCTION

1.1 INTRODUCTION 1

1.2 AIM 1

1.3 METHODOLOGY 11.4 SIGNIFICANCE 1

2 LITERATURE REVIEW

2.1 AIM 2

2.2 BLOCK DIAGRAM 3

2.3 METHODOLOGY 4

2.4 IR TRANSMITTER & IR RECEIVER 4

2.5 SCHEMATIC DIAGRAM 7

2.6 SCHEMATIC DIAGRAM EXPLANATION 8

3 HARDWARE COMPONENTS

3.1 AT89S52 MICROCONTROLLER 9

3.1.1 DISCRIPTION 9

3.1.2 FEATURES 10

3.1.3 BLOCK DIAGRAM 11

3.1.4 PIN DIAGRAM 12

3.1.5 PIN DISCRIPTION 13


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3.2 POWER SUPPLY 21

3.3 REGULATOR 21

3.4 TRANSFORMER 22

3.5 CAPACITOR FILTER 233.6 LEDS 24

3.6.1 FUNCTION 24

3.6.2 CONNECTING 24

3.6.3 TESTING AN LED 25

3.7 IR LED 25

3.7.1 DESCRIPTION 26

3.7.2 FEATURES 26

3.8 LCD INTEERFACING 26

3.8.1 INTRODUCTION 26

3.8.2 PIN DISCRIPTION 26

4 WORKING FLOW OF PROJECT

4.1 BLOCK DIAGRAM 31

4.2 CIRCUIT DESCRIPTION 32

4.3 SOFTWARE 33

4.3.1 KEIL VISION 33

4.3.2 EMBEDDED 34

5 CONCLUSION 35

REFERENCES 36


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ABSTRACT

Traffic is formally organized in many jurisdictions, with marked lanes, sjunctions,

intersections, interchanges, traffic signals, or signs. Traffic is often classified by type:

heavy motor vehicle (e.g., car, truck); other vehicle (e.g., moped, bicycle); andpedestrian. Different classes may share speed limits and easement, or may be segregated.

Some jurisdictions may have very detailed and complex rules of the road.

One of the main problems in our citys is traffic, this project proposed new

solution to traffic control. The main design accept of this project is to control the traffic

automatically and adding human inelegancy to that automatic controller. "Four-way"

intersection is the most common configuration for roads that cross each other, and the

most basic type. If signals do not control a 4-way intersection, signs or other features are

typically used to control movements and make clear priorities.

In this project we are going to use IR communication to analyze traffic density.

IR signals from IR receiver are given to microcontroller and microcontroller gives

appropriate result according to traffic. For better result we are going to use some bunch of

IR transmitters and IR receivers in all directions. When there is a more traffic in one side

more no. of IR receivers will not get the signals and result will compare with all other

directions and microcontroller gives green signals at one side where more no of IR

receivers will not get the signals.

For IR communication we are using an IR transmitter and IR receiver. Here IR

LED will acts as a transmitter. As we know microcontroller having inbuilt I/O ports and

we are interfacing IR receivers to those I/O ports. For controlling of traffic we are using

red, green and yellow color LEDs. These LEDs are connected to different I/O ports of

microcontroller. When there is a more traffic microcontroller gives signal to green LED

and it will glow. So by using this project we can control the traffic automatically like a

human being.

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LIST OF FIGURES

FIG.NO TITLE PAGE.NO

1 A JUNCTION WITH LED & IR SENSORS 1

2 BLOCK DIAGRAM 2

3 CIRCUIT OF IR TRANSMITTER 4

4 CIRCUIT OF IR RECEIVER 4

5 SCHEMATIC DIAGRAM OF CIRCUIT 6

6 AT89S52 MICROCONTROLLER 9

7 BLOCK DIAGRAM OF AT89S52 MICROCONTROLLER 10

8 PIN DIAGRAM OF AT89S52 119 OSCILLATOR CONNECTIONS 18

10 EXTERNAL CLOCK DRIVE CONFIGURATION 19

11 REGULATED POWER SUPPLY 20

12 EXAMPLE CIRCUIT SHOWING 5V DC OUTPUT 21

13 AN ELECTRICAL TRANSFORMER 22

14 LED 23

15 CIRCUIT DIAGRAM OF LED 2316 IR LED 24

17 SCHEMATIC DIAGRAM OF IR LED 24

18 BLOCK DIAGRAM OF WORKING OF PROJECT 30

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LIST OF TABLES

TABLE.NO TITLE PAGE.NO

1 PORTS SHOWING THE ALTERNATE FUNCTIONS ATPORT 1

12

2 PORTS SHOWING THE ALTERNATE FUNCTIONS ATPORT 3

14

3 TIMER 2 OPERATING MODES 17

4 PIN DISCRIPTION OF LCD 26

5 EMBEDDED C DATA TYPES 33

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Chapter-1

INTRODUCTION

1.1 Introduction:

In this system IR sensors are used to measure the density of the vehicles which are fixed within a fixed

distance.All the sensors are interfaced with the microcontroller which in turn controls the traffic signal

systemaccordingtodensitydetectedbythesensors

If the traffic density is high on particular side more priority is given for that side. The sensors

continuously keep sensing density on all sides and the green signal is given to the side onpriority basis,

where the sensors detect highdensity. The side with next priority level follows the first priority

level. Byusing thissystemtraffic can becleared without irregularitiesand timedelayseven thoughthere

isnotrafficontheother side canbeavoided

1.2 Aim:

ThemainAimofthisproject istocontrol the traffic lightsbasedonthe densityofthevehicles.

1.3 Methodology:

The project is to solve traffic congestion which is a severe problem in many modern

cities all over the world. To solve the problem, we have designed a framework for a

dynamic and automatic traffic light control system and developed a simulation model

with codes in to help build the system on hardware. Generally, each traffic light on anin te rsecti on is assi gned a const ant green signal time. It is possible to propose

dynamic time-based coordination schemes where the green signal time of the traffic

lights is assigned based on the present conditions of traffic. The intelligent work which is

done by traffic inspector will be perfectly done by the microcontroller in the circuit with

the help of sensors and the program which is coded to themicrocontroller.

1.4 Significance Of The Project:

This type of project is used in heavy traffic roads and the junction because this type of

project is based on the time as well as the density and the time will be controlled by

programme coded in microcontroller and the density will be controlled by IR sensors and

they are controlled by microcontroller

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Chapter-2

LITERATURE REVIEW

2.1 Introduction:

The project intelligent traffic management system for metro cites, is based on the

microcontroller which will provide the controlling of the traffic depending upon the

density.

According to the signaling i.e. continuity between the IR transmitter and IR receiver the

Timing of the green, red lights will be glown for the particular time depending upon the

density.

The micro controller will monitor the all control functionalities. According to the

controller signalling the density will be monitored by lights.

Microcontroller based traffic control system is an application specific project, which is

used to control the traffic. An embedded system is developed which consists of a

microcontroller, IR transmitter and receiver, LEDs

This project is implemented by placing IR transmitters, receivers and leds at the 4 way

junction, the four paths are represented as R1,R2,R3,R4

FIG 1: A JUNCTION WITH LED & IR SENSORS

Transmitters and receivers are placed at either sides of the four paths, and 4 leds at

corner of the junction When there is a traffic along the paths,value of R would be 000

which are the values of IR sensors and if there is no traffic the value is 111


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2

2.2 Block Diagram:

FIG 2: BLOCK DIAGRAM

3

Micro

controller

(ATS8952)

POWER

SUPPLY

Signals from IR

receivers from

all directions

RED

GREEN

ROAD 3

RED

GREEN

ROAD 4

RED

GREEN

ROAD 1RED

GREEN

ROAD 2

IRTransmitter

signals

From all

directions


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2.3Block Diagram Explanation:

The main objective of this project is to control the traffic depending upon

the density .As there is much time wastage with the traffic lights which involves the

Time, we are designing the new system which controls the traffic depending upon the

density.

Here we place IR transmitter and the IR receivers at both ends of the roads. Whenever

the vehicles pass in-between them the continuity will be lost. Hence the microcontroller

senses the density is high.

Then the microcontroller will be making the light (green) to be glow much time at the

place where the traffic is high.

The same procedure will be followed by four sides of the road. The signalling from the

four sides will be taken into consideration and depending upon the density controller will

make the decision .

The system uses a compact circuitry build around flash version of AT89S52

Microcontroller with a non-volatile memory. Programs will be developed in

EMBEDDED C language. FLASH MAGIC is used for loading of programs into

microcontroller.

2.4 IR Transmitter & Receiver:

The purpose of the transmitter is to transform the information we want to send into a

signal that can be propagated by the channel. In the case of our wired copper channel, this

means we want the information to be transformed into a modulated voltage level,

something like the pulse train. For a wireless channel, however, the transmitter needs to

encode the information onto an EM wave that can be easily propagated.

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IR Transmitter:

FIG 3: CIRCUIT OF IR TRANSMITTER

The IR transmitter part consists of an Infra red light emitting diode that can capable of

sending modulated data within infra red band. To match the receiver frequency the the

data is modulated at 38.7 KHZ by configuring 555 timer at astable mode of operation,

which generates frequency using the components R2 and C2 as shown in above fig. This

frequency can be varied over a long range just by varying the preset R1 and C1.

IR Receiver:

FIG 4: CIRCUIT OF IR RECEIVER

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The IR receiver consists of TSOP 1738 module which is a simple yet effective IR

proximity sensor built around the TSOP 1738 module. The TSOP module is commonly

found at the receiving end of an IR remote control system; e.g., in TVs, CD players etc.

These modules require the incoming data to be modulated at a particular frequency and

would ignore any other IR signals. It is also immune to ambient IR light, Such modules

are available for different carrier frequencies from 32 kHz to 42kHz.

In this particular proximity sensor, we will be generating a constant stream of square

wave signal using IC555 centered at 38 kHz and would use it to drive an IR led. So

whenever this signal bounces off the obstacles, the receiver would detect it and change its

output. Since the TSOP 1738 module works in the active-low configuration, its output

would normally remain high and would go low when it detects the signal (the obstacle).

Basically an ir sensor is used for detecting an obstacle, there are some areas where

valuable things are placed, an IR transmitter and receiver is placed there, an infrared path

is established and if any person comes into that path the buzzer gets on which gives out a

long beep Similarly a fire sensor is used to detect fire

The sensed data is given to the microcontroller, processing is done according to the logic

in the microcontroller and then writes onto GSM which will further send sms to the

mobile at the user

A buzzer is interfaced to microcontroller to give out a beep sound whenever an obstacle

and fire is detected

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2.5 Schematic Diagram:

FIG 5: SCHEMATIC DIAGRAM OF CIRCUIT

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2.6 Schematic Explanation:

Power Supply:

The schematic diagram gives the basic hardware connections used in the

project. Beginning from the power supply the secondary of the step-down transformer

wires are given to the two ends (2,4) of bridge rectifier which is having the four diodes in

the bridge formate.The other two ends 1,3)are connected to the input(pin 1) and output

pin 3 of the 7805 regulator and pin no 2 is connected to ground as shown in schematic

diagram. The 1000 micro farad capacitor is connected in between the bridge rectifier

and regulator to eliminate the ac ripples presented in the rectified output. The 100 micro

farad capacitor is used to eliminate the noise at regulator output. Now 5V is available at

the pin no 3 of regulator and connected to pin no 40 of micro controller.

AT89S52 micro controller :

The 8051 micro controller consists 40 pins and every pin has its own functionality as

shown in the schematic diagram.

The port 0 is having the pull up resistor which is having eight 10K resistors in

parallel each connected to the each pin of it.

IR Led:

The IR LED is arranged with a resistor ,in such a way that Vcc is applied to the positive

terminal of the IR LED.These are connected to the port 1 of the microcontroller.

IR Receiver:

The IR receivers are arranged with the transistor logic as shown in the diagram.

The two transistors are connected in such a manner that collector terminal is connected to

the base terminal of the other. The photo diode is connected to the base of the transistor

along with the combination of the resistor.

The IR Receivers are connected to the port 2 P2.0,,P2.1,P2.2,P2.3 pins of the

microcontroller.

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Chapter-3

HARDWARE COMPONENTS

3.1 AT89S52 Microcontroller:

3.1.1 Description:

The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller

with 8K bytes of in-system programmable Flash memory. The device is

manufactured using Atmels high-density nonvolatile memory technology and is

compatible with the indus-try-standard 80C51 instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed in-system or by a

conventional nonvolatile memory pro-grammer. By combining a versatile 8-bit

CPU with in-system programmable Flash on a monolithic chip, the Atmel

AT89S52 is a powerful microcontroller which provides a highly-flexible and cost-

effective solution to many embedded control applications. The AT89S52 provides

the following standard features: 8K bytes of Flash, 256 bytes of RAM, 32 I/O

lines, Watchdog timer, two data pointers, three 16-bit timer/counters, a six-vector

two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and

clock circuitry. In addition, the AT89S52 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 con-tents but freezes the oscillator, disabling

all other chip functions until the next interrupt or hardware reset.

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FIG 6: AT89S52 MICROCONTROLLER

3.1.2 Features :

Compatible with MCS-51 Products

8K Bytes of In-System Programmable (ISP) Flash Memory

4.0V to 5.5V Operating Range

Fully Static Operation: 0 Hz to 33 MHz

Three-level Program Memory Lock

256 x 8-bit Internal RAM

32 Programmable I/O Lines

Three 16-bit Timer/Counters

Eight Interrupt Sources

Full Duplex UART Serial Channel

Low-power Idle and Power-down Modes

Interrupt Recovery from Power-down Mode

Watchdog Timer

Dual Data Pointer

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Power-off Flag

Fast Programming Time

Flexible ISP Programming (Byte and Page Mode)

Green (Pb/Halide-free) Packaging Option

3.1.3BlockDiagram:

FIG 7: BLOCK DIAGRAM OF AT89S52 MICROCONTROLLER

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3.1.4 Pin Diagram:

FIG 8: PIN DIAGRAM OF AT89S52

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Pin Description:

VCC: Supply voltage.

GND: Ground.

PORT 0: Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each

pin can sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as

high-impedance inputs. Port 0 can also be configured to be the multiplexed low-order

address/data bus during accesses to external program and data memory. In this mode, P0

has internal pull-ups. Port 0 also receives the code bytes during Flash programming and

outputs the code bytes dur-ing program verification.

PORT 1:

Port 1 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 1 output buffers

can sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high

by the inter-nal pull-ups and can be used as inputs. As inputs, Port 1 pins that are

externally being pulled low will source current (IIL) because of the internal pull-ups. In

addition, P1.0 and P1.1 can be configured to be the timer/counter 2 external count input

(P1.0/T2) and the timer/counter 2 trigger input (P1.1/T2EX), respectively, as shown in

the follow-ing table. Port 1 also receives the low-order address bytes during Flash

programming and verification.

TABLE 1: PORTS SHOWING THE ALTERNATE FUNCTIONS AT PORT 1

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PORT 2:




externally being pulled low will source current (IIL) because of the internal pull-ups. Port

2 emits the high-order address byte during fetches from external program memory and

dur-ing accesses to external data memory that use 16-bit addresses (MOVX @ DPTR). In

this application, Port 2 uses strong internal pull-ups when emitting 1s. During accesses to

external data memory that use 8-bit addresses (MOVX @ RI), Port 2 emits the contents

of the P2 Special Function Register. Port 2 also receives the high-order address bits and

some control signals during Flash program-ming and verification.

Port Pin Alternate Functions:

P1.0 T2 (external count input to Timer/Counter 2), clock-out P1.1 T2EX (Timer/Counter

2 capture/reload trigger and direction control) P1.5 MOSI (used for In-System

Programming) P1.6 MISO (used for In-System Programming) P1.7 SCK (used for In-

System Programming)5 1919DMICRO6/

PORT 3:




externally being pulled low will source current (IIL) because of the pull-ups. Port 3

receives some control signals for Flash programming and verification. Port 3 also serves

the functions of various special features of the AT89S52, as shown in the fol-lowing

table.

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PSEN: Program Store Enable (PSEN) is the read strobe to external program

memory.When the AT89S52 is executing code from external program memory, PSEN is

activated twice each machine cycle, except that two PSEN activations are skipped

XTAL1: Input to the inverting oscillator amplifier and input to the internal clock

operating circuit.

XTAL2 :Output from the inverting oscillator amplifier.

Program Memory:

If the EA pin is connected to GND, all program fetches are directed to external memory.

On the AT89S52, if EA is connected to VCC, program fetches to addresses 0000H

through 1FFFH are directed to internal memory and fetches to addresses 2000H through

FFFFH are to external memory.

Data Memory: The AT89S52 implements 256 bytes of on-chip RAM. The upper 128

bytes occupy a parallel address space to the Special Function Registers. This means that

the upper 128 bytes have the same addresses as the SFR space but are physically separate

from SFR space. When an instruction accesses an internal location above address 7FH,

the address mode used in the instruction specifies whether the CPU accesses the upper

128 bytes of RAM or the SFR space. Instructions which use direct addressing access the

SFR space. For example, the following direct addressing instruction accesses the SFR at

location 0A0H (which is P2). MOV 0A0H, #data Instructions that use indirect addressing

access the upper 128 bytes of RAM. For example, the following indirect addressing

instruction, where R0 contains 0A0H, accesses the data byte at address 0A0H, rather than

P2 (whose address is 0A0H). MOV @R0, #data Note that stack operations are examples

of indirect addressing, so the upper 128 bytes of data RAM are available as stack space.

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Watchdog Timer (One-Time Enabled With Reset-Out):

The WDT is intended as a recovery method in situations where the CPU may be

subjected to software upsets. The WDT consists of a 14-bit counter and the Watchdog

Timer Reset (WDTRST) SFR. The WDT is defaulted to disable from exiting reset. To

enable the WDT, a user must write 01EH and 0E1H in sequence to the WDTRST register

(SFR location 0A6H). When the WDT is enabled, it will increment every machine cycle

while the oscillator is running. The WDT timeout period is dependent on the external

clock frequency. There is no way to disable the WDT except through reset (either

hardware reset or WDT overflow reset). When WDT over-flows, it will drive an output

RESET HIGH pulse at the RST pin.

Using The WDT:

To enable the WDT, a user must write 01EH and 0E1H in sequence to the WDTRST

register (SFR location 0A6H). When the WDT is enabled, the user needs to service it by

writing 01EH and 0E1H to WDTRST to avoid a WDT overflow. The 14-bit counter

overflows when it reaches 16383 (3FFFH), and this will reset the device. When the WDT

is enabled, it will increment every machine cycle while the oscillator is running. This

means the user must reset the WDT at least every 16383 machine cycles. To reset the

WDT the user must write 01EH and 0E1H to WDTRST. WDTRST is a write-only

register. The WDT counter cannot be read or written. WhenWDT overflows, it will

generate an output RESET pulse at the RST pin. The RESET pulse dura-tion is

98xTOSC, where TOSC = 1/FOSC. To make the best use of the WDT, it should be

serviced in those sections of code that will periodically be executed within the time

required to prevent a WDT reset.

UART :The UART in the AT89S52 operates the same way as the UART in the

AT89S52 and AT89C52.

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Timer 0 and 1:

Timer 0 and Timer 1 in the AT89S52 operate the same way as Timer 0 and Timer 1 in

the AT89S52 and AT89C52.

Timer 2:

Timer 2 is a 16-bit Timer/Counter that can operate as either a timer or an event counter.

The type of operation is selected by bit C/T2 in the SFR T2CON (shown in Table 5-2).

Timer 2 has three operating modes: capture, auto-reload (up or down counting), and baud

rate generator. The modes are selected by bits in T2CON, as shown in Table 10-1. Timer

2 consists of two 8-bit registers, TH2 and TL2. In the Timer function, the TL2 register is

incremented every machine cycle. Since a machine cycle consists of 12 oscillator periods,the count rate is 1/12 of the oscil-lator frequency.

TABLE3: TIMER 2 OPERATING MODES

In the Counter function, the register is incremented in response to a 1-to-0 transition at its

corre-sponding external input pin, T2. In this function, the external input is sampled

during S5P2 of every machine cycle. When the samples show a high in one cycle and a

low in the next cycle, the count is incremented. The new count value appears in the

register during S3P1 of the cycle following the one in which the transition was detected.

Since two machine cycles (24 oscillator periods) are required to recognize a 1-to-0

transition, the maximum count rate is 1/24 of the oscillator frequency.

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To ensure that a given level is sampled at least once before it changes, the level should be

held for at least one full machine cycle.

Oscillator Characteristics:

XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier that

can be configured for use as an on-chip oscillator, as shown in Figure 16-1. Either a

quartz crystal or ceramic resonator may be used. To drive the device from an external

clock source, XTAL2 should be left unconnected while XTAL1 is driven, as shown in

Figure 16-2. There are no requirements on the duty cycle of the external clock signal,

since the input to the internal clock-ing circuitry is through a divide-by-two flip-flop, but

minimum and maximum voltage high and low time specifications must be observed.

FIG9: OSCILLATOR CONNECTIONS

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FIG 10: EXTERNAL CLOCK DRIVE CONFIGURATION

Programming The Flash Parallel Mode:

The AT89S52 is shipped with the on-chip Flash memory array ready to be programmed.

The programming interface needs a high-voltage (12-volt) program enable signal and is

compatible with conventional third-party Flash or EPROM programmers. The AT89S52

code memory array is programmed byte-by-byte.

Programming Algorithm:

Before programming the AT89S52, the address, data, and control signals should be set upaccording to the Flash Programming Modes (Table 22-1) and Figure 22-1 and Figure

22-2. To program the AT89S52, take the following steps: 1. Input the desired memory

location on the address lines. 2. Input the appropriate data byte on the data lines. 3.

Activate the correct combination of control signals. 4. Raise EA/VPP to 12V. 5. Pulse

ALE/PROG once to program a byte in the Flash array or the lock bits. The byte-write

cycle is self-timed and typically takes no more than 50 s. Repeat steps 1 through 5,

changing the address and data for the entire array or until the end of the object file is

reached.

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3.2 Power Supply:

The power supplies are designed to convert high voltage AC mains electricity to a

suitable low voltage supply for electronics circuits and other devices. A power supply can

by broken down into a series of blocks, each of which performs a particular function. A

d.c power supply which maintains the output voltage constant irrespective of a.c mains

fluctuations or load variations is known as Regulated D.C Power Supply

FIG 11: 5V REGULATED POWER SUPPLY

3.3 Voltage Regulator:

Voltage regulator ICs is available with fixed (typically 5, 12 and 15V) or variable output

voltages. The maximum current they can pass also rates them. Negative voltage

regulators are available, mainly for use in dual supplies. Most regulators include some

automatic protection from excessive current ('overload protection') and overheating

('thermal protection'). Many of the fixed voltage regulator ICs have 3 leads and look like

power transistors, such as the 7805 +5V 1A regulator shown on the right. The LM7805 is

simple to

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use. You simply connect the positive lead of your unregulated DC power supply

(anything from 9VDC to 24VDC) to the Input pin, connect the negative lead to the

Common pin and then when you turn on the power, you get a 5 volt supply from the

output pin.

FIG 12: EXAMPLE CIRCUIT SHOWING 5V DC OUTPUT

3.4 Transformer:

A transformer is an electrical device which is used to convert electrical power from one

Electrical circuit to another without change in frequency.

Transformers convert AC electricity from one voltage to another with little loss of

power. Transformers work only with AC and this is one of the reasons why mains

electricity is AC. Step-up transformers increase in output voltage, step-down

transformers decrease in output voltage. Most power supplies use a step-down

transformer to reduce the dangerously high mains voltage to a safer low voltage. The

input coil is called the primary and the output coil is called the secondary. There is no

electrical connection between the two coils; instead they are linked by an alternating

magnetic field created in the soft-iron core of the transformer. The two lines in the middle

of the circuit symbol represent the core. Transformers waste very little power so the

power out is (almost) equal to the power in. Note that as voltage is stepped down current

is stepped up. The ratio of the number of turns on each coil, called the turns ratio,

determines the ratio of the voltages. A step-down transformer has a large number of turns

on its primary (input) coil which is connected to the high voltage mains supply, and a

small number of turns on its secondary (output) coil to give a low output voltage.

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FIG 13: An Electrical Transformer

Turns ratio = Vp/ VS = Np/NS

Power Out= Power In

VS X IS=VP X IP

Vp = primary (input) voltage

Np = number of turns on primary coil

Ip = primary (input) current

3.5 Capacitor Filter:

We have seen that the ripple content in the rectified output of half wave rectifier is

121% or that of full-wave or bridge rectifier or bridge rectifier is 48% such high

percentages of ripples is not acceptable for most of the applications. Ripples can be

removed by one of the following methods of filtering.

(a) A capacitor, in parallel to the load, provides an easier by pass for the ripples voltage

though it due to low impedance. At ripple frequency and leave the d.c.to appears the load.

(b) An inductor, in series with the load, prevents the passage of the ripple current (due to

high impedance at ripple frequency) while allowing the d.c (due to low resistance to d.c)

(c) Various combinations of capacitor and inductor, such as L-section filter section

filter, multiple section filter etc. which make use of both the properties mentioned in (a)

and (b) above. Two cases of capacitor filter, one applied on half wave rectifier and

another with full wave rectifier.

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Filtering is performed by a large value electrolytic capacitor connected across the

DC supply to act as a reservoir, supplying current to the output when the varying DC

voltage from the rectifier is falling. The capacitor charges quickly near the peak of the

varying DC, and then discharges as it supplies current to the output. Filtering

significantly increases the average DC voltage to almost the peak value (1.4 RMS

value).

To calculate the value of capacitor(C),

C = *3*f*r*Rl

Where,

f = supply frequency,

r = ripple factor,

Rl = load resistance

Note: In our circuit we are using 1000F. Hence large value of capacitor is placed

to reduce ripples and to improve the DC component.

3.6 Light Emitting Diodes (LED'S):

Example: Circuit symbol:

FIG 14: LED FIG 15: CIRCUIT OF LED

3.6.1 Function:

LEDs emit light when an electric current passes through them.

3.6.2 Connecting And Soldering:

LEDs must be connected the correct way round, the diagram may be labelled a or

+ for anode and k or- for cathode (yes, it really is k, not c, for cathode!). The cathode is

the short lead and there may be a slight flat on the body of round LEDs. If you can see

inside the LED the cathode is the larger electrode (but this is not an official identification

method). 24


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LEDs can be damaged by heat when soldering, but the risk is small unless you are

very slow. No special precautions are needed for soldering most LEDs.

3.6.3 Testing An Led:

Never connect an LED directly to a battery or power supply!

It will be destroyed almost instantly because too much current will pass through and burn

it out. LEDs must have a resistor in series to limit the current to a safe value, for quick

testing purposes a 1k resistor is suitable for most LEDs if your supply voltage is 12V or

less. Remember to connect the LED the correct way round!

3.7 IR Led:

3.7.1 Description:The QED233 / QED234 is a 940 nm GaAs/AlGaAs LED encapsulated in a clear untinted,

plastic T-1 3/4 package.

FIG16: IR LED FIG17: SCHEMATIC OF IR LED

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3.7.2 Features:

Lambda= 940 nm

Chip material =GaAs with AlGaAs window

Package type: T-1 3/4 (5mm lens diameter)

Matched Photo sensor: QSD122/123/124

Medium Emission Angle, 40

High Output Power

Package material and color: Clear, untinted, plastic

Ideal for remote control applications

3.8 LCD Interfacing:

3.8.1 Introduction:

The most commonly used Character based LCDs are based on Hitachi's HD44780

controller or other which are compatible with HD44580. In this tutorial, we will discuss

about character based LCDs, their interfacing with various microcontrollers, various

interfaces (8-bit/4-bit), programming, special stuff and tricks you can do with these

simple looking LCDs which can give a new look to your application.

3.8.2 Pin Description:

The most commonly used LCDs found in the market today are 1 Line, 2 Line or 4 Line

LCDs which have only 1 controller and support at most of 80 characters, whereas LCDs

supporting more than 80 characters make use of 2 HD44780 controllers.

Most LCDs with 1 controller has 14 Pins and LCDs with 2 controller has 16 Pins (two

pins are extra in both for back-light LED connections). Pin description is shown in the

table below.

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TABLE 4: PIN DISCRIPTION OF LCD

27

Pin No. Name Description

Pin no. 1 VSS Power supply (GND)

Pin no. 2 VCC Power supply (+5V)

Pin no. 3 VEE Contrast adjust

Pin no. 4 RS0 = Instruction input

1 = Data input

Pin no. 5 R/W

0 = Write to LCD module

1 = Read from LCD

module

Pin no. 6 EN Enable signal

Pin no. 7 D0 Data bus line 0 (LSB)

Pin no. 8 D1 Data bus line 1






Pin no. 14 D7 Data bus line 7 (MSB)


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DDRAM - Display Data RAM:

Display data RAM (DDRAM) stores display data represented in 8-bit character codes. Its

extended capacity is 80 X 8 bits, or 80 characters. The area in display data RAM

(DDRAM) that is not used for display can be used as general data RAM. So whatever

you send on the DDRAM is actually displayed on the LCD. For LCDs like 1x16, only 16

characters are visible, so whatever you write after 16 chars is written in DDRAM

CGROM - Character Generator ROM:

Now you might be thinking that when you send an ASCII value to DDRAM, how the

character is displayed on LCD? So the answer is CGROM. The character generator ROM

generates 5 x 8 dot or 5 x 10 dot character patterns from 8-bit character codes (see Figure5 and Figure 6 for more details). It can generate 208 5 x 8 dot character patterns and 32 5

x 10 dot character patterns. User defined character patterns are also available by mask-

programmed ROM.As you can see in both the code maps, the character code from 0x00

to 0x07 is occupied by the CGRAM characters or the user defined characters. If user

wants to display the fourth custom character then the code to display it is 0x03 i.e. when

user sends 0x03 code to the LCD DDRAM then the fourth user created character or

pattern will be displayed on the LCD.

CGRAM - Character Generator RAM:

As clear from the name, CGRAM area is used to create custom characters in LCD. In the

character generator RAM, the user can rewrite character patterns by program. For 5 x 8

dots, eight character patterns can be written, and for 5 x 10 dots, four character patterns

can be written.

BF - Busy Flag:

Busy Flag is a status indicator flag for LCD. When we send a command or data to the

LCD for processing, this flag is set (i.e. BF =1) and as soon as the instruction is executed

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successfully this flag is cleared (BF = 0). This is helpful in producing and exact amount

of delay for the LCD processing.To read Busy Flag, the condition RS = 0 and R/W = 1

must be met and The MSB of the LCD data bus (D7) act as busy flag. When BF = 1

means LCD is busy and will not accept next command or data and BF = 0 means LCD is

ready for the next command or data to process.

Instruction Register (IR) and Data Register (DR):

There are two 8-bit registers in HD44780 controller Instruction and Data register.

Instruction register corresponds to the register where you send commands to LCD e.g.

LCD shift command, LCD clear, LCD address etc. and Data register is used for storing

data which is to be displayed on LCD. When send the enable signal of the LCD is

asserted, the data on the pins is latched in to the data register and data is then moved

automatically to the DDRAM andhenceisdisplayedontheLCD.

Data Register is not only used for sending data to DDRAM but also for CGRAM, the

address where you want to send the data, is decided by the instruction you send to LCD.

4-Bit Programming Of LCD:In 4-bit mode the data is sent in nibbles, first we send

the higher nibble and then the lower nibble. To enable the 4-bit mode of LCD, we need to

follow special sequence of initialization that tells the LCD controller that user has

selected 4-bit mode of operation. We call this special sequence as resetting the LCD.

Following is the reset sequence of LCD.

Wait for about 20mS

Send the first init value (0x30)

Wait for about 10mS

Send second init value (0x30)

Wait for about 1mS Send third init value (0x30)

Wait for 1mS

Select bus width (0x30 - for 8-bit and 0x20 for 4-bit)

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The busy flag will only be valid after the above reset sequence. Usually we do not use

busy flag in 4-bit mode as we have to write code for reading two nibbles from the LCD.

Instead we simply put a certain amount of delay usually 300 to 600uS. This delay might

vary depending on the LCD you are using, as you might have a different crystal

frequency on which LCD controller is running. So it actually depends on the LCD

module you are using. In 4-bit mode, we only need 6 pins to interface an LCD. D4-D7

are the data pins connection and Enable and Register select are for LCD control pins. We

are not using Read/Write (RW) Pin of the LCD, as we are only writing on the LCD so we

have made it grounded permanently. If you want to use it, then you may connect it on

your controller but that will only increase another pin and does not make any big

difference. Potentiometer RV1 is used to control the LCD contrast. The unwanted data

pins of LCD i.e. D0-D3 are connected to ground.

Sending data/command in 4-bit Mode:

We will now look into the common steps to send data/command to LCD when working

in 4-bit mode. In 4-bit mode data is sent nibble by nibble, first we send higher nibble and

then lower nibble. This means in both command and data sending function we need to

separate the higher 4-bits and lower 4-bits.The common steps are:

Mask lower 4-bits

Send to the LCD port

Send enable signal

Mask higher 4-bits

Send to LCD port

Send enable signal

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Chapter-4

WORKING FLOW OF THE PROJECT&CONCLUSION

4.1 Block Diagram:

FIG 18: BLOCK DIAGRAM OF WORKING OF PROJECT

This project is mainly designed to reduce traffic problems. i.e. in general the four sides of

the road at a signal point are controlled at regular intervals of time with a certain time

delay. But in order to reduce the time at one side of the signal point with respect to the

other side where there is more traffic we use IR sensors. It mainly consists of a

microcontroller.

31

8051

MICRO

CONTROLLER

LCD

IR

RECIEVER

IR

TRANSMITTER

REGULATED

POWERSUPPLY


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IR transmitter placed nearer to the signal point and when it detects more density of traffic

at any side it and it transmits signal to the receiver. The receiver receives this signal to the

microcontroller. Thus accordingly the LCD displays the time depending on the density of

traffic. Here the regulated power supply is used to drive the microcontroller. Hence with

the help of IR transmitter we can easily control traffic.

4.2 Circuit Description:

In this project we required operating voltage for Microcontroller 89C51 is 5V. Hence the

5V D.C. power supply is needed for the ICs. This regulated 5V is generated by stepping

down the voltage from 230V to 18V now the step downed a.c voltage is being rectified

by the Bridge Rectifier using 1N4007 diodes. The rectified a.c voltage is now filtered

using a C filter. Now the rectified, filtered D.C. voltage is fed to the Voltage Regulator.

This voltage regulator provides/allows us to have a Regulated constant Voltage which is

of +5V. The rectified; filtered and regulated voltage is again filtered for ripples using an

electrolytic capacitor 100F. Now the output from this section is fed to 40thpin of 89C51

microcontroller to supply operating voltage. The microcontroller 89C51 with Pull up

resistors at Port0 and crystal oscillator of 11.0592 MHz crystal in conjunction with

couple of 30-33pf capacitors is placed at 18th

& 19th

pins of 89s52 to make it work

(execute) properly.

One of the main problems in our citys is traffic, this project proposed new

solution to traffic control. The main design accept of this project is to control the traffic

automatically and adding human inelegancy to that automatic controller. "Four-way"

intersection is the most common configuration for roads that cross each other, and the

most basic type. If signals do not control a 4-way intersection, signs or other features are

typically used to control movements and make clear priorities.

For IR communication we are using an IR transmitter and IR receiver. Here IR

LED will acts as a transmitter. As we know microcontroller having inbuilt I/O ports and

we are interfacing IR receivers to those I/O ports. For controlling of traffic we are using

red, green and yellow color LEDs.

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These LEDs are connected to different I/O ports of microcontroller. When there is a

more traffic microcontroller gives signal to green LED and it will glow. So by using this

project we can control the traffic automatically like a human being.

4.3 Software:

Software used is:

*Keil software for C programming

*Express PCB for lay out design

*Express SCH for schematic design

4.3.1 Keil Vision:

What's New in Vision3?

Vision3 adds many new features to the Editor like Text Templates, Quick Function

Navigation, and Syntax Coloring with brace high lighting Configuration Wizard for

dialog based startup and debugger setup. Vision3 is fully compatible to Vision2 and

can be used in parallel with Vision2.

What is Vision3?

Vision3 is an IDE (Integrated Development Environment) that helps you write, compile,

and debug embedded programs. It encapsulates the following components:

A project manager.

A make facility.

Tool configuration.

Editor.

A powerful debugger.

Express PCB: Express PCB is a Circuit Design Software and PCB manufacturing

service. One can learn almost everything you need to know about Express PCB from the

help topics included with the programs given.

Details: Express PCB, Version 5.6.0

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Express SCH:

The Express SCH schematic design program is very easy to use. This

software enables the user to draw the Schematics with drag and drop options. A Quick

Start Guide is provided by which the user can learn how to use it.

Details: Express SCH, Version 5.6.0

4.3.2 Embedded C:

The programming Language used here in this project is an

Embedded C Language. This Embedded C Language is different from the generic C

language in few things like

a) Data types

b) Access over the architecture addresses.

The Embedded C Programming Language forms the user friendly language with access

over Port addresses, SFR Register addresses etc.

Data Types Size in Bits Data Range/Usage

unsigned char 8-bit 0-255

signed char 8-bit -128 to +127

unsigned int 16-bit 0 to 65535

signed int 16-bit -32,768 to +32,767

sbit 1-bit SFR bit addressable only

Bit 1-bit RAM bit addressable only

sfr 8-bit RAM addresses 80-FFH

only

TABLE5: EMBEDDED C DATA TYPES

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Chapter-5

CONCLUSION

The project density based traffic control system has been successfully designed

and tested. Integrating features of all the hardware components used have developed it.

Presence of every module has been reasoned out and placed carefully thus contributing to

the best working of the unit. Secondly, using highly advanced ICs and with the help of

growing technology the project has been successfully implemented.

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References:

[1]. The 8051 Micro controller and Embedded Systems-Muhammad Ali Mazidi,Janice

Gillispie Mazidi

[2]. The 8051 Micro controller Architecture Programming & Applications-KennethJ.Ayala

[3]. Fundamentals Of Micro processors and Micro computers -B.Ram

[4]. Micro processor Architecture, Programming & Applications -Ramesh

S.Gaonkar

[5]. Electronic Components -D.V.Prasad

[6]. Wireless Communications - Theodore S. Rappaport

[7]. Mobile Tele Communications - William C.Y. Lee

REFERENCE ON WEB:

www.national.com

www.nxp.com

www.8052.comwww.microsoftsearch.com

www.geocities.com

project report on dynamic traffic system

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