INTELLIGENT TRAFIC LIGHTS SYSTEM

The intelligent traffic signal control aims at optimization of time spent at any intersection by the visiting vehicular traffic. The parameters considered are the mass density of the traffic on each leaf of the intersection and waiting time at each signal. Consider the following two cases:

Case 1: An intersection with equal flow of traffic in all directions.

This represents a theoretical case as the present design scenario of any metropolitan indicates that traffic depends not only on the density of population inhabiting it but, also on the usage of roads and highways and also the time of the day. Equal flow implies that the time allotted to each signal for clearance of traffic on its side can be set as same. The time can vary, but, equally for all sides, according to the decent time requirements for that specific road. An example of such an intersection could be taken to be any one on the roads which do not lie on the main road or national highways.

Let the mass density on leaf 1 be m₁ vehicles/m² and the time the signal is on be t₁ sec.

Let the mass density on leaf 2 be m₂ vehicles/m² and the time the signal is on be t₂ sec.

Let the mass density on leaf 3 be m₃ vehicles/m² and the time the signal is on be t₃ sec.

Let the mass density on leaf 4 be m₄ vehicles/m² and the time the signal is on be t₄ sec.

This case represents the condition wherein

m₁=m₂=m₃=m₄=m

i.e. t₁=t₂=t₃=t₄=t

The time t can be chosen to clear a certain block of traffic which can be chosen in accordance to the amount of traffic that frequents that intersection. Here in optimization of time is achieved by choosing the minimum block.

Case 2:

In practice, such a scenario does not occur on most frequented roads as the flow on these is in one direction only. As such consider the case when the following conditions exist:

m₁>m₂=m₃=m₄.

Now if t₁=t₂=t₃=t_4,

Then the time for which the signal stays on would be according to the highest mass density i.e. m₁, so as to make it possible for maximum traffic to be cleared at one time and prevent clogging of road. Let us say that the number of vehicles cleared in that time be x. In most of the practical situations, the traffic on the lower density leaf is less than x.

intersection and faster flow.

WORKING

The main modules for the project are as follows:

1. Power Supply
2. Control Units
3. Sensing unit ( For each site)

Display unit ( For Signals) According to the input from site having maximum density. We can also set the control unit to serve the site according to the priority basis for each site.Our Intruder circuit will act as traffic density sensor at four ends.

It consists of following parts

• ELECTRO-OPTICAL CONVERTER:

This module converts the electrical signal into light signal, which are transmitted through Infrared Rays or wireless communication. In a light source forms the carrier and must also be modulated to transmit information. Usually the transmitter simply turns the light source on and off.

• OPTICAL TO ELECTRIC CONVERTER:

To decode the information from the light pulses, some type of light detector must be employed. The detector's job is to convert the light signals, collected at the receiver, into electrical signals. It is the intensity or power of the light that determines its strength. Therefore, the real job of the light detector is to convert light power into electrical power, independent of the energy of the transmitted light pulses. This relationship also implies that the conversion is independent of the duration of the light pulses used.

Microcontrollers for embedded systems

In the literature discussing microprocessors, we often see a term embedded system. Microprocessors and microcontrollers are widely used in embedded system products. An embedded product uses a microprocessor (or microcontroller) to do one task and one task only. A printer is an example of embedded system since the processor inside it performs one task only: namely, get data and print it. Contrasting this with IBM PC which can be used for a number of applications such as word processor, print server, network server, video game player, or internet terminal. Software for a variety of applications can be loaded and run. Of course the reason a PC can perform myriad tasks is that it has RAM memory and an operating system that loads the application software into RAM and lets the CPU run it. In an embedded system, there is only one application software that is burned into ROM. An PC contains or is connected to various embedded products such as the keyboard, printer, modem, disk controller, sound card, CD-ROM driver, mouse and so on. Each one of these peripherals has a microcontroller inside it that performs only one task. For example, inside every mouse there is a microcontroller to perform the task of finding the mouse position and sending it to the PC. Although microcontrollers are the preferred choice for many embedded systems, there are times that a microcontroller is inadequate for the task. For this reason, in many years the manufacturers for general-purpose microprocessors have targeted their microprocessor for the high end of the embedded market.

Voltage Source Or Power Supply

This circuit is a small +5 volts power supply, which is useful when experimenting with digital electronics. Those transformers are easily available, but usually their voltage regulation is very poor, which makes them not very usable for digital circuit experimenter unless a better regulation can be achieved in some way. The following circuit is the answer to the problem.

For step down transformer, N₁>N₂, i.e., numbers of turns of primary winding is more than those in secondary.

· SENSORS

A sensor is a type of transducer, or mechanism, that responds to a type of energy by producing another type of energy signal, usually electrical. They are either direct indicating (an electrical meter) or are paired with an indicator (perhaps indirectly through an analog to digital converter, a computer and a display) so that the value sensed is translated for human understanding. Types of sensors include electromagnetic, chemical, biological and acoustic. Aside from other applications, sensors are heavily used in medicine, industry and robotics.

In order to act as an effectual sensor, the following guidelines must be met:

• the sensor should be sensitive to the measured property
• the sensor should be insensitive to any other property
• the sensor should not influence the measured property

In theory, when the sensor is working perfectly, the output signal of a sensor is exactly proportional to the value of the property it is meant to measure. The gain is then defined as the ratio between output signal and measured property. For example, if a sensor measures temperature and has an actual voltage output, the gain is a constant with the unit.

When the sensor is not perfect, various deviations can occur, including gain error, long term drift, and noise. These and other deviations can be classified as systematic, or random, errors. Systematic deviations may be compensated for by means of some kind of calibration strategy. Noise is an example of a random error that can be reduced by signal processing, such as filtering, usually at the expense of the dynamic behavior of the sensor.

· TRANSFORMER

Transformer works on the principle of mutual inductance. We know that if two coils or windings are placed on the core of iron, and if we pass alternating current in one winding, back emf or induced voltage is produced in the second winding. We know that alternating current always changes with the time. So if we apply AC voltage across one winding, a voltage will be induced in the other winding. Transformer works on this same principle. It is made of two windings wound around the same core of iron. The winding to which AC voltage is applied is called primary winding. The other winding is called as secondary winding.

Voltage and current relationship:

Let V₁ volts be input alternating voltage applied to primary winding. I₁ Amp is input alternating current through primary winding. V₂ volt is output alternating voltage produced in the secondary. I₂ amp be the current flowing through the secondary.

Then relationship between input and output voltages is given by

V₁/V₂ = N₁/N₂

Relationship between input and output currents is

I₁/I₂ = N₂/N₁

(Where N₁ is no. of turns of coil in primary and N₂ is number of turns in secondary )

We know that Power = Current X Voltage. It is to be noted that input power is equal to output power. Power is not changed. If V₂ is greater than V₁, then I₂ will be less than I₁. This type of transformer is called as step up transformer. If V₁ is

greater than V₂, then I₁ will be less than I₂. This type of transformer is called as step down transformer.

For step up transformer, N₂>N₁, i.e., number of turns of secondary winding is more than those in primary.

MICROCONTROLLERS FOR EMBEDDED SYSTEMS

In that they remain code compatible with the 8051. This has led to many versions of the 8051 with different speeds and amount of on-chip ROM marketed by more than half a dozen manufacturers. It is important to know that although there are different flavors of the 8051, they are all compatible with thin the literature discussing microprocessors, we often see a term embedded system. Microprocessors and microcontrollers are widely used in embedded system products. An embedded product uses a microprocessor (or microcontroller) to do one task and one task only. A printer is an example of embedded system since the processor inside it performs one task only: namely, get data and print it. Contrasting this with a IBM PC which can be used for a number of applications such as word processor, print server, network server, video game player, or internet terminal. Software for a variety of applications can be loaded and run. Of course the reason a PC can perform myriad tasks is that it has RAM memory and an operating system that loads the application software into RAM and lets the CPU run it. In an embedded system, there is only one application software that is burned into ROM. An PC contains or is connected to various embedded products such as the keyboard, printer, modem, disk controller, sound card, CD-ROM driver, mouse and so on. Each one of these peripherals has a microcontroller inside it that performs only one task. For example, inside every mouse there is a microcontroller to perform the task of finding the mouse position and sending it to the PC.

Although microcontrollers are the preferred choice for many embedded systems, there are times that a microcontroller is inadequate for the task. For this reason, in many years the manufacturers for general-purpose microprocessors have targeted their microprocessor for the high end of the embedded market.

INTRODUCTION TO 8051

In 1981, Intel Corporation introduced an 8-bit microcontroller called the 8051. This microcontroller had 128 bytes of RAM, 4K bytes of on-chip ROM, two timers, one serial port, and four ports (8-bit) all on a single chip. The 8051 is an 8-bit processor, meaning the CPU can work on only 8- bit pieces to be processed by the CPU. The 8051 has a total of four I/O ports, each 8- bit wide. Although 8051 can have a maximum of 64K bytes of on-chip ROM, many manufacturers put only 4K bytes on the chip.

The 8051 became widely popular after Intel allowed other manufacturers to make any flavor of the 8051 they please with the conditioe original 8051 as far as the instructions are concerned. This means that if you write your program for one, it will run on any one of them regardless of the manufacturer. The major 8051 manufacturers are Intel, Atmel, Dallas Semiconductors, Philips Corporation, Infineon.

WATER LEVEL CONTROLLER

first part of project

For complete project go to http://electronicsforengineers.blogspot.com/search/label/WATER%20LEVEL%20CONTROLLER%20PROJECT

INTRODUCTION

It is the circuit which will be used in house water tank, water tanks of buildings. It is a fully automatic circuit, if someone used this circuit then there is no need of fill the water tank daily, switch on/off the motor daily. It automatically operate without the permision of the user. Once the circuit operates, it will do their job for infinitely unless the circuit is damage.

PRINCIPLE

It is based upon the principle of conduction of water. We give earth to the water. When the water rises in the tank then the desired pins are conducting. Therefore the logic circuit acts as zero. It may be noted that the gates used in our circuit is made from the transister transister logic. If the input of any gate is kept open then it doesn’t mean that the input is zero. Open input acts as one. When we grounded the pin then it acts as zero.

continued to WATER LEVEL CONTROLLER 2

WATER LEVEL CONTROLLER 2

Second part of project

For complete project go to http://electronicsforengineers.blogspot.com/search/label/WATER%20LEVEL%20CONTROLLER%20PROJECT

COMPONENTS USED

Gates:

Following are the gates used in project:

Nand gates: These gates which we used in project are made from the transister transister logics.These gates are embebbed in 7400 series. IC no. for the nand gate is 7400. This IC contain 4 two input nand gate. The ground voltage is given to the 7^th pin whereas supply voltage is given to the 14^th pin. The numbering is started in anticlockwise from the cut. The truth table for nand gate is:

A0 A1 Output

0 0 1

0 1 1

1 0 1

1 1 0

Not gates:

Not gate is also called an inverse gate because it inverse the input. IC no. for the not gate is 7404. It contain 6 two input not gate. Truth table for the not gate is

Input output

0 1

1 0

Selector switch:Selector switch is a rotating switch. It is many input one output switch.It select the particular input and fed it to the output. In our project we have three output from the logic circuit so one output is selected at a time with the help of selector switch.

Relay:Relay is a powerful component in the electronic world. It acts as a switch. It operates on logic operations. Relay consist of a copper coil. The output of any logic circuit is given to the relay. It consist of four pin. One pin is connected to the neutral, one is connected to the main 220V supply and other two is connected to the output of the logic gates. It works on the principle of magnetic field. When the output of the logic circuit is one means 5V, then a magnetic field is produced inside the coil. Due to this magnetic field a magnetic force occur. This force attract the iron piece which is mounted above the centre of the coil. As a result the circuit is completed and a relay gives a output of 220V. when the output of the logic gates is zero then 0V is applied to the relay. Therefore no magnetic field is produced inside the coil and relay acts as a open circuit.

Water pump:

Water pump is simply used to push the water from the ground to the tank. Water pump is off many types depending upon its types on the basis of size, wattage etc. A tripical used water pump is a rotating blade type pump. When the blades inside the pump is rotated then the pump release water with a high pressure.

Transformer:

We used step down transformer in our project. This transformer step down the 220V of AC supply to 5V. Thus the number of turns in the secondary winding is less then the number of turns in primary winding.

Diodes:Diode act as a switch. When the postive side of the battery is connected to the p side of the diode then it act as a closed switch but when the postive terminal is connected to the n side of the diode then it acts as a open switch.

Capactor:Capactor is used to store the charge. It allow the DC supply but block the ac supply. Thus it is used as a filter for the dc supply. In our project it is used in rectifier circuit for filter the dc output.

Bell:Bell is used simply to alert the consumer. Its one terminal is connected to the positive dc supply other is connected to the A3 terminal of the tank. When water rises to the A3 terminal then it is grounded and the circuit is completed and bell vibrates.

WORKING

Working with gates: Initially when the tank is empty then all the four pins in the tank are open. These open pins are acts as 1.Let us consider the case of output Q1 because other case of Q2 and Q3 are similar to the Q1. Output Q1 depends upon the two input that is A0 and A3. lets suppose the initially output of Q1 is zero. This output is fed back to the gate G6. The other input of the G6 is the output of G6’ not gate, which is zero thus the two inputs of the G6 is zero so the output of the G6 (which is nand gate) is 1. This output of G6(which is1) is fed back as the input of G5, other input of the G4 is also 1( as open pin A3 act as 1). So the output of the G5 which is Q1 is zero. Thus the output of the logic circuit is zero. When the output of the logic circuit is zero then relay acts as a closed switch (because initially the spring of the relay completed the circuit. The circuit only break when the magnetic field is produced. This magnetis field oppose the spring force and relay acts as open circuit) Therefore relay, switch on the motor and the tank starts filling.

Now suppose the initial output Q1 is 1. This output is fed back as the input of the G6. Other input of G6 is already 0. so the output of this nand gate is 1. This output is fed back as the input of G5 whose one input is already one. So output Q1 is again zero. Thus unless the initial conditions the output depends upon the pins A0 and A3 when the tank is empty.

When the motor starts running, the level of the water in the tank starts rising. When the level reaches the pin A0, it become zero because water is grounded. Again the output of G6’ become one,and one input of G6 is 1 and other is zero(feed back input). Thus the output of G6 become one. This output is fed back as the input of G5 thus the two input of G5 become one and the output become again zero. Thus motor runnig althrough water level reaches to A0.

When the level reaches to A3 ( whose one pin is already one) its one input become zero and the output of the Q1 becomes 1. when the output of the logic circuit is one then the relay acts as open circuit. Thus motor stops.

Again when we use the water, therefore water level starts decreasing. when the water level decreases from A3, one input become one. Initially when the level of the water is on A3 the output is one. So when water falls from this level, this output is fed back(which is one). Thus the two inputs of G6 become one, and output become zero. This zero is fed back as one input of G5(whose one input is one). Thus output of G5 again become one and the motor remain stops at this condition.

Now when the level decreases from A0 then again all the condition discussed above is applied(which we applied when the tank is empty). And the output of Q1 become zero and the motor starts running.

RESULTS

WHEN WATER RISES

A0	A1	A2	A3	Q1	Q2	Q3
1	1	1	1	0	0	0
0	1	1	1	0	0	0
0	0	1	1	0	0	0
0	0	0	1	0	0	0
0	0	0	0	1	1	1

WHEN WATER FALLS

A0	A1	A2	A3	Q1	Q2	Q3
0	0	0	0	1	1	1
0	0	0	1	1	1	1
0	0	1	1	1	1	0
0	1	1	1	1	0	0
1	1	1	1	0	0	0

PURPOSE OF THREE OUTPUTS:

When we select the output Q1, it means that motor is only on when the tank is empty completely.

When we select the output Q2, it means that motor is only on when the water level in the tank is 1/3. Thus when the water level decrease from 1/3 level of the tank, motor automatically on and fil the tank again.

When we select the output Q3, it mean the motor is on only when the water level in the tank is 2/3.

ADVANTAGES

These three output is given to the selector switch. The selector switch selects only one output at a time. Thus we select the output level according to our need. For example in some areas there is lot of electric cuts, so they want their tanks filled with water all the time because of lack of regular electricity. So in our circuit they select the output Q3. The advantage of this is that, the level of water in their tanks will always above two third of the tank.

SOURCE OF DC SUPPLY:

A step down transformer is used. This transformer step down the 220V of ac to 5V. This 5V is given to the to the wheatstone bridge. Wheatstone bridge consist of 4 diodes and a capacter. Two diodes are set with same polarity whereas the other diodes are set with different polarity as the arm of the bridge. When the cycle of the ac is positive, the two diodes is forward biased whereas other two are reversed biased. The output is taken across the capactor which gives the pure dc supply.

ROLE OF LED:

Full form of LED is light emitting diode. When LED is forward biased it glows. So these LED ars used to indicate the level of the water. We give 5V to all the LED and other pin are dipped in 5 different levels in water. LED only glows when the water reaches the pins. Thus the level of the water is determined with the help of these LED’s.

ELECTRIC BELL:

Electric bell is used for the indication of the tank filled signal. To take the advantage of this bell, it depends upon the interest of the user because it is connected to the on\off switch. If some one does not want any bell signal, then they switch off the bell. One input of this bell is directly connected to the positive terminal of dc supply whereas the other input is connected to the A3 pin. When the water reaches the level A3, this terminal is grounded and the circuit of the bell is completed.

MANUAL ON \ OFF SWITCH:

This switch is introduced for more advantage of the user. When this switch is on then the motor on directly and at this condition the logic circuit is off. This is done with the help of the two way switch. When we switch on the motor manually then the logic action off automatically. And when we switch off this manual switch then the logic circuit operates automatically.

ADVANTAGE OF THIS MANUAL SWITCH:

Suppose someone know that the light is gone after 10 minutes and he wants to fill the tank before the electricity gone. So at this condition, the manual switch is very helpful. To take more advantage from this manual switch, switch on the bell.

POWER SWITCH:

Power switch is simply used to isolate the circuit from the main, when we don’t used this circuit.

APPLICATIONS

It is very useful circuit in case of areas facing electricity problems. It will help a lot due to its automatic on/off operation and there is no necessity that tank must be empty to start the motor, but can be adjusted to one-third or two-third of level.