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    Table of Contents

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    2. Literature survey

    3.Formation of the Problem

    4.System specification

    5.Design of solution

    6.Implementation7.Results and Discussions

    8.System testing

    9.Conclusion and future scope


    List of FiguresFigure 2.1 A typical embedded system block diagramFigure 2.2 The structure of a GSM networkFigure 4.1: AT89C51 Pin DiagramFigure 4.2 Oscillator and timing circuitFigure 4.3 SMOD RegisterFigure 4.4 TCON RegisterFigure 4.5 TMOD RegisterFigure 4.6 IE RegisterFigure 4.7 IP RegisterFigure 4.8 PSW Register

    Figure 4.9 PORT3 Alternate UseFigure 4.10 Data framingFigure 4.11 Data transferFigure 4.12 SCON RegisterFigure 4.13 UART modes

    Figure 4.14Voltage levels for RS232 and TTL


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    The main objective of this project is to control the traffic lights based on

    the density of the vehicles.


    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 system according to density detected by the


    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 on priority basis, where the sensors detect high density. The side with

    next priority level follows the first priority level.

    By using this system traffic can be cleared without irregularities and time delays

    even though there is no traffic on the other side can be avoided.

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    Embedded C.


    KEIL uvision2 IDE


    1. PCB for micro controllers

    2. 8051 controller,

    3. DB9 Connectors

    4. IR sensor pairs

    5. Red, green LEDs

    6. 11.0592 MHz quartz crystal,

    7. Resistors, Capacitors

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    IR - E

    Power supply to all sections


    Traffic signal


    Key board

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    The overview of this project is to implement Density based traffic controlling system using IRtechnology and 89S52 controller. 89S52 is very efficient architecture which can be used for lowend security systems and IR is widely adapted technology for communication.


    Purpose of the current work is to study and analyse the counting and controlling system by using8051 controller.

    1.3 Scope

    Current work focuses on how to use effectively IR and 8051 controllers for digital securitysystems.


    Literature survey

    2.1 Embedded Systems

    An embedded system is a special-purpose computer system designed to perform one or a few dedicatedfunctions, often with real-time computing constraints. It is usually embeddedas part of a complete deviceincluding hardware and mechanical parts. In contrast, a general-purpose computer, such as a personalcomputer, can do many different tasks depending on programming. Embedded systems control many ofthe common devices in use today.

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    Since the embedded system is dedicated to specific tasks, design engineers can optimize it, reducing thesize and cost of the product, or increasing the reliability and performance. Some embedded systems aremass-produced, benefiting from economics of scale. Physically, embedded systems range from portabledevices such as digital watches and mp4 players, to large stationary installations like traffic lights, factorycontrollers, or the systems controlling nuclear power stations. Complexity varies from low, with a singlemicrocontroller chip, to very high with multiple units, peripherals and networks mounted inside a largechassis or enclosure.

    In general, "embedded system" is not an exactly defined term, as many systems have some element ofprogrammability. For example, handheld computers share some elements with embedded systems suchas the operating systems and microprocessors which power them but are not truly embedded systems,because they allow different applications to be loaded and peripherals to be connected

    2.2 Characteristics

    1. Embedded systems are designed to do some specific task, rather than be a general-purposecomputer for multiple tasks. Some also have real-time performance constraints that must be met,for reasons such as safety and usability; others may have low or no performance requirements,allowing the system hardware to be simplified to reduce costs.

    2. Embedded systems are not always standalone devices. Many embedded systems consist of small,computerized parts within a larger device that serves a more general purpose. For example, thefeatures an embedded system for tuning the strings, but the overall purpose of the Robot Guitaris, of course, to play music. Similarly, an embedded system in automobiles provides a specificfunction as a subsystem of the car itself.

    3. The program instructions written for embedded systems are referred to as firmware, and arestored in read-only memory or flash memory chips. They run with limited computer hardwareresources: little memory, small or non-existent keyboard and/or screen.

    Figure 2.1 A typical embedded system block diagram

    2.3 Micro Controllers

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    The micro controller, nowadays, is an indispensable device for electrical/electronic engineers

    and also for technicians in the area, because of its versatility and its enormous application. .Born

    of parallel developments in computer architecture and integrated circuit fabrication ,the

    microprocessor or computer on chip first becomes a commercial reality in 1971.with the

    introduction of the 4 bit 4004 by a small, unknown company by the name of Intel corporation.

    Other, well established, semiconductor firms soon followed Intels pioneering technology so

    that by the late 1970s we could choose from a half dozen or so micro processor typThe 1970s

    also saw the growth of the number of personal computer users from a Handful of hobbyists and

    hackers to millions of business, industrial, governmental, defense, and educational and private

    users now enjoying the advantages of inexpensive computing.

    A bye product of microprocessor development was the micro controller. The same fabrication

    techniques and programming concepts that make possible general-purpose microprocessor also

    yielded the micro controller.

    Among the applications of a micro controller we can mention industrial automation,

    mobile telephones, radios, microwave ovens and VCRs. Besides, the present trend in digital

    electronics is toward restricting to micro controllers and chips that concentrate a great quantity

    of logical circuits, like PLDs (Programmable Logic Devices) and GALs (Gate Array Logic).

    In dedicated systems, the micro controller is the best solution, because it is cheap and easy to


    2.6 Communication:

    Communication refers to the sending, receiving and processing of information by electric

    means. As such, it started with wire telegraphy in the early 80s, developing with telephony and

    radio some decades later. Radio communication became the most widely used and refined through

    the invention of and use of transistor, integrated circuit, and other semi-conductor devices. Most

    recently, the use of satellites and fiber optics has made communication even more wide spread, with an

    increasing emphasis on computer and other data communications.

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    A modern communications system is first concerned with the sorting, processing and storing of

    information before its transmission. The actual transmission then follows, with further processing and

    the filtering of noise. Finally we have reception, which may include processing steps such as decoding,

    storage and interpretation. In this context, forms of communications include radio, telephony and

    telegraphy, broadcast, point to point and mobile communications (commercial and military), computer

    communications, radar, radio telemetry and radio aids to navigation. It is also important to consider the

    human factors influencing a particular system, since they can always affect its design, planning and use.

    Wireless communication has become an important feature for commercial products and a

    popular research topic within the last ten years. There are now more mobile phone subscriptions than

    wired-line subscriptions. Lately, one area of commercial interest has been low-cost, low-power, and

    short-distance wireless communication used for personal wireless networks." Technology advancements

    are providing smaller and more cost effective devices for integrating computational processing,

    wireless communication, and a host of other functionalities. These embedded communications devices

    will be integrated into applications ranging from homeland security to industry automation and

    monitoring. They will also enable custom tailored engineering solutions, creating a revolutionary way

    of disseminating and processing informatio