Traffic Signal Controller

DEPARTMENT OF ELECTRICAL ENGINEERING

SUBMITTED BY----

CALCUTTA INSTITUTE OF ENGINEERING & MANAGEMENT

ANINDYA HOME CHOUDHURY(EE-421)ANUP SINGHA(EE-422)

ARINDAM DUTTA(EE-423)AVIK BAKSHI(EE-424)

GROUP 6

AUTOMATIC TRAFFIC SIGNAL CONTROLLER

DEPARTMENT OF ELECTRICAL ENGINEERING

APPROVED BY----

Coordinator Project Guide Head of Department (Dr. Samiran Choudhuri) (Mrs. Reshmi (Mr. Subhasish Banerjee) Bannerjee)

CALCUTTA INSTITUTE OF ENGINEERING & MANAGEMENT

PREFACE

We feel happy to present our final year project report on “Automatic Traffic Signal Controller”. It was a great learning process and was a great experience to work together in a team. Our main goal is to design this controller which Ensures orderly movement of traffic in all directions and Provisions for pedestrians to cross the street safely. We designed the model in a bread board and with the use of proper logic and accuracy we successfully completed it. We faced a few technical hitches earlier but later it was solved with the help of our teachers.

ACKNOWLEDGEMENT

Dreams never turn to reality unless a lot of effort and hard work is put in to it. And no effort bears fruit in the absence of support and guidance. It takes a lot of effort to work your way through this goal and having someone to guide you and help you is always a blessing. We would like to take this opportunity to thank a few who were closely involved in the completion of this project. Ingenuity and popular guidance are inevitable for successful completion of a project. We are indebted to all sources that helped me in working out this project at each steps of its progress.

First and foremost Prof. (Dr.) Swapan Chandra Sarkar, Principal, for granting permission to proceed with the project and providing the necessary facilities/ We sincerely thanks Mr. Subhasish Bannerjee, the Head of department, Department of Electrical engineering, for the valuable help provided to me. In particular we are extremely grateful to Project coordinator Prof. Dr. Samiran Choudhuri and Project guide Mrs. Reshmi Banerjee lecturer, Department of Electrical Engineering for their valuable suggestion and proper guidance to complete our project. Above all we thank the lord almighty for giving us all the confidence and ability to achieve this dream!

AUTOMATED TRAFFIC SIGNAL CONTROLLER

This automated traffic signal controller can be made by suitably programming GAL device. Its main features are: -

1. The controller assumes equal traffic density on all the roads.

2. In most automated traffic signals the free left-turn condition is provided throughout the entire signal period, which poses difficulties to the pedestrians in crossing the road, especially when the traffic density is high. This controller allows the pedestrians to safely cross the road during certain periods.

3. The controller uses digital logic, which can be easily implemented by using logic gates.

4. The controller is a generalized one and can be used for different roads with slight modifications.

5. The control can also be exercised manually when desired. The time period for which green, yellow and red traffic signals remain ‘on’ (and then repeat) for the straight moving traffic is divided into eight units of 8 Seconds (or multiples thereof) each.

CONTENTS:

1. INTRODUCTION History Technology

2. THE PROJECT Design procedure The working of system

3. THE CIRCUITCircuit Diagram Bread Board Layout Components Used

4. Description of Major Components IC-CD4011 Astable Multivibrator 74160 IC7408 IC 7432 IC 7411 IC 7404 IC Resistors &Capacitors Light Emitting Diode

5. Advantages & Disadvantages

1. INTRODUCTION:-

Now a days due to ever increasing vehicles on the road, it requires an efficient control on the four way junction of road. In order to find a solution to this problem the concept of an automatic traffic controller is conceived. Apart from providing efficient control of traffic, it also eliminate chance of human errors since it function automatically.

The automatic traffic controller automatically switches on the four way junction for 15 seconds for direction control.

The main circuit components used are IC CD4011 and 4-bit binary synchronous counter (74160). The IC CD4011 generates a clock signal for 15 seconds. This signal is used to clock counter circuit. Binary counter is converted to 3 bit–counter to achieve 8 possible cases. The traffic light control is done by different Boolean function of logic gate.

History:-The modern electric traffic light is an American invention. As early as 1912 in Salt Lake City, Utah, Policeman Lester Wire invented the first red-green Electric traffic lights. On 5 August 1914, the American Traffic Signal Company installed a traffic signal system on the corner of East 105th Street and Euclid Avenue in Cleveland, Ohio. It had two colors, red and green, and a buzzer, based on the design of James Hodge, to provide a warning for color changes. The design by James Hodge allowed police and fire stations to control the signals in case of emergency.

The first four-way, three-color traffic light was created by police officer William Potts in Detroit, Michigan in 1920.In 1923, Garrett Morgan Patented a traffic signal device. It was Morgan‘s experience while driving along the streets of Cleveland that led to his invention of a traffic signal device. Ashville, Ohio claims to be the location of the oldest working traffic light in the United States, used at an intersection of public roads until 1982 when it was moved to a local museum.

The first interconnected traffic signal system was installed in Salt Lake City in 1917, with six connected intersections controlled simultaneously from a manual switch. Automatic control of interconnected traffic lights was introduced March 1922 in Houston, Texas. The first automatic experimental traffic lights in England were deployed in Wolverhampton in 1927.

TECHNOLOGY:-Optics and lighting:-

In the mid 1990s, cost-effective traffic light lamps using light-emitting diodes (LEDs) were developed; prior to this date traffic lights were designed using incandescent or halogen light bulbs. Unlike the incandescent-based lamps, which use a single large bulb, the LED-based lamps consist of an array of LED elements, arranged in various patterns. When viewed from a distance, the array appears as a continuous light source. LED-based lamps (or 'lenses') have numerous advantages over incandescent lamps; among them are:

• Much greater energy efficiency (can be solar-powered).

• Much longer lifetime between replacement, measured in years rather than months. Part of the longer lifetime is due to the fact that some light is still displayed even if some of the LEDs in the array are dead.

• Brighter illumination with better contrast against direct sunlight, also called 'phantom light'.

• The ability to display multiple colors and patterns from the same lamp. Individual LED elements can be enabled or disabled, and different color LEDs can be mixed in the same lamp

• Much faster switching.

• Instead of sudden burn-out like incandescent-based lights, LEDs start to gradually dim when they wear out, warning transportation maintenance departments well in advance as to when to change the light. Occasionally, particularly in green LED units, segments prone to failure will flicker rapidly beforehand.

The operational expenses of LED-based signals are far lower than equivalent incandescent-based lights. As a result, most new traffic light deployments in the United States, Canada and elsewhere have been implemented using LED-based lamps; in addition many existing deployments of incandescent traffic lights are being replaced. In 2006, Edmonton, Alberta, Canada completed a total refit to LED-based lamps in the city's over 12,000 intersections and all pedestrian crosswalks. Many of the more exotic traffic signals discussed on this page would not be possible to construct without using LED technology. However, color-changing LEDs are in their infancy and may surpass the multi-color array technology.

In some areas, LED-based signals have been fitted (or retrofitted) with special Fresnel lenses (Programmed Visibility or 'PV' lenses) and/or diffusers to limit the line of sight to a single lane. These signals typically have a "projector"-like visibility; and maintain an intentionally limited range of view. Because the LED lights don't generate a significant amount of heat, heaters may be necessary in areas which receive snow, where snow can accumulate within the lens area and limit the visibility of the indications.

Another new LED technology is the use of CLS (Central Light Source) optics. These comprise around 7 high-output LEDs (sometimes 1 watt) at the rear of the lens, with a diffuser to even out and enlarge the light. This gives a uniform appearance, more like traditional halogen or incandescent luminaries. Replacing halogen or incandescent reflector and bulb assemblies behind the lens with an LED array can give the same effect. This also has its benefits: minimal disruption, minimal work, minimal cost and the reduced need to replace the entire signal head (housing).

2.THEPROJECT

Design procedure:-

The working of the system:-

The corresponding circuit automatically controls the traffic signal

during the day as well as nights.

In this system there are one 555 timer and one 74160 synchronous 4 bit counter, which is controlling whole device. Along with there are some electronic equipments like 7404, 7408, 7411 gate, capacitor, resistor, LED (yellow, green, red) etc. The time period for which green, yellow, and red traffic signals remain ‘on’ (And then repeat) for the straight moving traffic is divided into eight units of 8 seconds (or multiples thereof) each.

This automated traffic signal controller can be made by suitably programming a GAL device. Its main features are:

1. The controller assumes equal traffic density on all the roads.

2. In most automated traffic signals the free left-turn condition is provided throughout the entire signal period, which poses difficulties to the pedestrians in crossing the road, especially when the traffic density is high. This controller allows the pedestrians to safely cross the road during certain periods.

3. The controller uses digital logic, which can be easily implemented by using logic gates.

4. The controller is a generalized one and can be used for different roads with slight modification.

5. The control can also be exercised manually when desired

TRAFFIC FLOW DIAGRAM:-

Fig. above shows the flow of traffic in all permissible directions during the eight time units of 8 seconds each. For the left- and right turning traffic and pedestrians crossing from north to south, south to north, east to west ,and west to east, only green and red signals are used.

SIMULTANEOUS STATES TABLE:-

Table I shows the simultaneous states of the signals for all the traffic. Each row represents the status of a signal for 8 seconds. As can be observed from the table, the ratio of green, yellow, and red signals is 16:8:40 (=2:1:5) for the straight moving traffic. For the turning traffic the ratio of green and red signals is 8:56 (=1:7), while for pedestrians crossing the road the ratio of green and red signals is 16:48 (=2:6) In Table II (as well as Table I) X, Y, and Z are used as binary variables to depict the eight states of 8 seconds each. Letters A through H indicate the left and right halves of the roads in four directions as shown in Fig. 1. Two letters with a dash in between indicate the direction of permissible movement from a road. Straight direction is indicated by St, while left and right turns are indicated by Lt and Rt, respectively. The Boolean functions for all the signal conditions are shown in Table II. The left- and the right-turn signals for the traffic have the same state, i.e. both are red or green for the same duration, so their Boolean functions are identical and they should be connected to the same control output. The circuit diagram for realizing these Boolean functions is shown in circuit diagram. IC CD4011 (IC1) is wired as an astable multivibrator to generate clock signal for the 4-bit counter 74160 (IC2).

BOOLEAN EXPRESSION:-

The time duration of IC1 can be adjusted by varying the value of resistor or capacitor C of the clock circuit. The ‘on’ time duration T is given by the following relationship: T = RC, IC2 is wired as a 3-bit

binary counter by connecting its Q3 output to reset pin 1 via inverter N1. Binary outputs Q2, Q1, and Q0 form variables X, Y, and Z, respectively. These outputs, along with their complimentary outputs X’, Y’, and Z’, respectively, are used as inputs to the rest of the logic circuit to realize various outputs satisfying Table I. You can simulate various traffic lights using green, yellow, and red LEDs and feed the outputs of the circuit to respective LEDs via current-limiting resistors of 470 ohms each to check the working of the circuit. Here, for turning traffic and pedestrians crossing the road, only green signal is made available. It means that for the remaining period these signals have to be treated as ‘red’ in practice, the outputs of Fig. 2 should be connected to operate high – power bulbs. Further, if a particular signal condition (such as turning signal) is not applicable to a given road, the output of that signal condition should be connected to green signal of the next state (refer Table I).

The traffic signals can also be controlled manually, if it desired. Any signal state can be established by entering the binary value corresponding to that particular state into the parallel input pins of the 3-bit counter. Similarly, the signal can be reset at any time by providing logic 0 at the reset pin (pin 1) of the counter using an external switch.

3. THE

CIRCUIT

CIRCUIT DIAGRAM:-

Bread Board Layout :-

COMPONENTS REQUIRED:-

Components Specification Quantity

1.Capacitors 1μf,16v

2

2.Resistors 1MΩ

470Ω

2

1

18

3LED Green

Red

Yellow

10

4

4

4.IC CD 4011

74160

7432

7404

7411

7408

1

1

2

1

3

1

4. Description of Major Components

INTEGRATED CIRCUITS:

Integrated Circuits are usually called ICs or chips. They are complex circuits which have been etched onto tiny chips of semiconductor (silicon). The chip is packaged in a plastic holder with pins spaced on a 0.1" (2.54mm) grid which will fit the holes on strip board and breadboards. Very fine wires inside the package link the chip to the pins.

Pin numbers

The pins are numbered anti-clockwise around the IC (chip) starting near the notch or dot. The diagram shows the numbering for 8-pin and 14-pin ICs, but the principle is the same for all sizes.

IC CD4011:-

These quad gates are monolithic complementary MOS (CMOS) integrated circuits constructed with N- and P-channel enhancement mode transistors. They have equal source and sink current capabilities and conform to standard B series output drive.

The astable multivibrator circuit uses two CMOS NAND gates and thus giving a clock pulse to the counter.

Astable multivibrator using two CMOS nand gates as shown in the above figure

C1=C2=C

R1=R2=R

The total period :

T = RC

Using R1=1MΩ, R2=1MΩ, C1=1uF, C2= 1uF

Then T= CR=1X10^-6 X1 X 10^6

T=1s => each unit of 1 seconds theoretically.

IC CD 4011=> DATASHEET

74160 IC:-

74160 synchronous decade counter (standard reset) 74161 synchronous 4-bit counter (standard reset) 74162 synchronous decade counter (synchronous reset) 74163 synchronous 4-bit counter (synchronous reset)

These are synchronous counters so their outputs change precisely together on each clock pulse. This is helpful if you need to connect their outputs to logic gates because it avoids the glitches which occur with ripple counters. The count advances as the clock input becomes high (on the rising-edge). The decade counters count from 0 to 9 (0000 to 1001 in binary). The 4-bit counters count from 0 to 15 (0000 to 1111 in binary). For normal operation (counting) the reset, preset, count enable and carry in inputs should all be high. When count enable is low the clock input is ignored and counting stops. The counter may be preset by placing the desired binary number on the inputs A-D, making the preset input low, and applying a positive pulse to the clock input. The inputs A-D may be left unconnected if not required. The reset input is active-low so it should be high (+Vs) for normal operation (counting). When low it resets the count to zero (0000, QA-QD low), this happens immediately with the 74160 and 74161 (standard reset), but with the 74162 and 74163 (synchronous reset) the reset occurs on the rising-edge of the clock input. Counting to less than the maximum (15 or 9) can be achieved by connecting the appropriate output(s) through a NOT or NAND gate to the reset input. For the 74162 and 74163 (synchronous reset) you must use the output(s) representing one less than the reset count you require, e.g. to reset on 7 (counting 0 to 6) use QB (2) and QC (4).

Connecting synchronous counters in a chain the diagram below shows how to link synchronous counters such as 74160-3, notice how all the clock (CK) inputs are linked. Carry out (CO) is used to feed the carry in (CI) of the next counter. Carry in (CI) of the first 74160-3 counter should be high.

IC 74160=> DATASHEET

7408 IC:-The AND gate is a digital logic gate that implements logical conjunction. In another sense, the function of AND effectively finds the minimum between two binary digits, just as the OR function finds the maximum. The AND gate with inputs A and B and output C Implements the logical expression.

7408 IC=> DATA SHEET

7432 IC:-As its name implies, an OR logic gate performs an ”OR“ logic operation, which is an addition. So, OR logic gate can be summarized by the formula Y = A + B.

7432 IC=> DATA SHEET

7411 IC:-It is a triple 3input and gate. Its Boolean expression is given by

7411 IC=> DATA SHEET

7404 IC:-

In digital logic, an inverter or NOT gate is a logic gate which implements logical negation.

7404 IC=> DATA SHEET

CAPACITORS:-Function:-

Capacitors store electric charge. They are used with resistors in timing circuits because it takes time for a capacitor to fill with charge. They are used to smooth varying DC supplies by acting as a reservoir of charge. They are also used in filter circuits because capacitors easily pass AC (changing) signals but they block DC (constant) signals.

There are many types of capacitor but they can be split into two groups, polarised and unpolarised. Each group has its own circuit symbol.

Polarised capacitors (large values, 1μF +)

Unpolarised capacitors (small values, up to 1μF)

RESISTORS:-Function

Resistors restrict the flow of electric current, for example a resistor is placed in series with a light-emitting diode (LED) to limit the current passing through the LED.

Resistor values - the resistor colour code:

Most resistors have 4 bands: • The first band gives the first digit. • The second band gives the second digit. • The third band indicates the number of zeros.

• The fourth band is used to show the tolerance (precision) of the resistor,

this may be ignored for almost all circuits.

= brown+black+green

= 1 MΩ

Light Emitting Diode:-

Circuit symbol:

Function LEDs emit light when an electric current passes through them

Colours of LEDs LEDs are available in red, orange, amber, yellow, green, blue

and white. Blue and white LEDs are much more expensive than the other colours.

Calculating an LED resistor value

An LED must have a resistor connected in series to limit the current through the LED, otherwise it will burn out almost instantly. The resistor value, R is given by: R=(VS - VL) / I

For example: If the supply voltage VS = 9V, and you have a red LED (VL = 2V), requiring a current I = 20mA = 0.020A, R = (9V - 2V) / .02A = 350, so choose 390 (the nearest standard value which is greater).

Advantages of this controller :- 1. Simple and efficient circuit2. Working requirement is easily met.3. No instant and direct manual operation is needed.4. Consumes very small amount of power for Operation.5. It also saves a considerable amount of power.6. A very practical and low cost device.7. It can make to work by using solar cell/wind cell for power requirements.

Disadvantages of this Controller:-

1. It is not applicable in case of unequal traffic Density.2. The circuit becomes a lot more complicated if it is a 6 or 8 way traffic.

Future scope:-

This is the basic circuit which is to be implemented to control traffic signals automatically.

In real time traffic density is unequal. A sensor can be introduced to sense the traffic at each hour and thereby interfacing it with a microcontroller (8051)

Instead of using digital logic microprocessor based programming or PLC(programmable logic controller)can be used to avoid complex circuitry.

Fuzzy logic based traffic junction light simulator system may be introduced to overcome the difficulties in the real environment.

Future of the traffic signal is named as RHODES(Real Time Hierarchical Optimized Distributed Effective System) which looks down the roads for waves of approaching the traffic, estimates when that traffic will arrive at that signal.

CONCLUSION:-

It gives me immense pleasure to write that project was completed successfully. We hope this unique opportunity provided to me by The Calcutta Institute of Engineering and Management, Kolkata will in future help us in designing different types of controllers. The controller we designed as proved to be a cost effective process and moreover solving the Conflicting traffic movements, hence allowing normal flow of traffic avoiding accidents. We are really grateful that got this project and successfully finished it.

Bibliography:-

• 1.www.electronics.com• 2.www.electronicsforu.com• 3.www.google.com• 4.www.kpsec.freeuk.com• 5.www.wikipedia.org