16-11-2012, 12:13 PM
DENSITY BASED TRAFFIC CONTROL SYSTEM
DENSITY BASED TRAFFIC.DOC (Size: 2.01 MB / Downloads: 182)
ABSTRACT
An adaptive traffic control system was developed where the traffic load is continuously measured by sensors connected to a microcontroller-based system which also performs all intersection control functions. Intersection controllers of an area are interconnected with a communication network through which traffic load and synchronization information is exchanged.
As a result, the duration and relative phases of each traffic light cycle change dynamically. For the basic function of the system only the intersection controllers are required.
INTRODUCTION
Implementation
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, LED’s
This project is implemented by placing IR transmitters, receivers and led’s at the 4 way junction, the four paths are represented as R1,R2,R3,R4
For instance,let the traffic at the path R1 be initially 111 ie there is no traffic , when the traffic reaches the first sensor,the value of R would be 011,if it reaches second sensor ,the value of R is 001,and then if it reaches the last sensor that is the third one,it is recognized that traffic is heavy and the led glows which indicates that vehicles can move forward,traffic is cleared, and the sensor values automatically changed to 111.the control goes to the next path wher the values of sensors contains more no of zeroes
This entire embedded system is placed at that junction Microcontroller is interfaced with led’s and ir sensors The total no of IR sensors required are 12 and led’s 4 Therefore these are connected to any two ports of microcontroller
BLOCK DIAGRAM DESCRIIPTION
The block diagram consists of microcontroller interfaced to regulated power supply, led and IR receiver and IR transmitter which consists of an IR sensor
The IR sensors and leds are connected to any of the port pins of microcontroller,regulated power supply is connected to the Vcc pin of microcontroller which uses an voltage regulator to get 5 v of power supply. The transmit pin of IR receiver is connected to the receive pin of microcontroller
This embedded system is placed at the 4 way junction which controls the traffic electronically 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.
IR TRANSMITTER and 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.
EMBEDDED SYSTEM
An embedded system is a special-purpose computer system designed to perform one or a few dedicated functions[1], sometimes with real-time computing constraints. It is usually embedded as part of a complete device including hardware and mechanical parts. In contrast, a general-purpose computer, such as a personal computer, can do many different tasks depending on programming. Embedded systems have become very important today as they control many of the common devices we use.
Since the embedded system is dedicated to specific tasks, design engineers can optimize it, reducing the size and cost of the product, or increasing the reliability and performance. Some embedded systems are mass-produced, benefiting from economies of scale.
Physically, embedded systems range from portable devices such as digital watches and MP3 players, to large stationary installations like traffic lights, factory controllers, or the systems controlling nuclear power plants. Complexity varies from low, with a single microcontroller chip, to very high with multiple units, peripherals and networks mounted inside a large chassis or enclosure.
INTRODUCTION TO EMBEDDED SYSTEM
We are living in the Embedded World. You are surrounded with many embedded products and your daily life largely depends on the proper functioning of these gadgets. Television, Radio, CD player of your living room, Washing Machine or Microwave Oven in your kitchen, Card readers, Access Controllers, Palm devices of your work space enable you to do many of your tasks very effectively. Apart from all these, many controllers embedded in your car take care of car operations between the bumpers and most of the times you tend to ignore all these controllers.
In recent days, you are showered with variety of information about these embedded controllers in many places. All kinds of magazines and journals regularly dish out details about latest technologies, new devices, fast applications which make you believe that your basic survival is controlled by these embedded products. Now you can agree to the fact that these embedded products have successfully invaded into our world. You must be wondering about these embedded controllers or systems. What is this Embedded System?
MICROCONTROLLER
In contrast to general-purpose CPUs, microcontrollers may not implement an external address or data bus as they integrate RAM and non-volatile memory on the same chip as the CPU. Using fewer pins, the chip can be placed in a much smaller, cheaper package.
Integrating the memory and other peripherals on a single chip and testing them as a unit increases the cost of that chip, but often results in decreased net cost of the embedded system as a whole. Even if the cost of a CPU that has integrated peripherals is slightly more than the cost of a CPU + external peripherals, having fewer chips typically allows a smaller and cheaper circuit board, and reduces the labor required to assemble and test the circuit board.