14-08-2012, 01:47 PM
INTELLIGENT TRAFFIC AMBULANCE
AN INTILLEGENT TRAFIC AMBULANCE.docx (Size: 1.76 MB / Downloads: 44)
CHAPTER 1
INTRODUCTION
1.1 EMBEDDED SYSTEMS
Embedded systems are designed to do some specific task, rather than be a general-purpose computer for multiple tasks. Some also have real time performance constraints that must be met, for reason such as safety and usability; others may have low or no performance requirements, allowing the system hardware to be simplified to reduce costs.
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 information. With new technologies and devices come new business activities, and the need for employees in these technological areas. Engineers who have knowledge of embedded systems and wireless communications will be in high demand. Unfortunately, there are few adorable environments available for development and classroom use, so students often do not learn about these technologies during hands-on lab exercises. The communication mediums were twisted pair, optical fiber, infrared, and generally wireless radio.
ABSTRACT
Many traffic light systems operate on a timing mechanism that changes the lights after a given interval. An intelligent traffic ambulance senses the presence or absence of vehicles and reacts accordingly. The idea behind intelligent traffic ambulance systems is that drivers will not spend unnecessary time waiting for the traffic lights to change. Since the waiting time of the vehicles for the lights to change is optimal, the emission of carbon monoxide from the vehicles is reduced. This will give a positive effect to the green house effect towards the environment. The system developed is able to sense the presence or absence of vehicles within certain range by setting the appropriate duration for the traffic signals to react accordingly using keypad. The system can help to solve the problem of traffic congestion.
The main aim in designing and developing of the Intelligent Traffic ambulance system it consists of a computer that controls the selection and timing of traffic movements in accordance to the varying demands of traffic signal as registered to the controller unit by keypad through zigbee communication. The second part is the signal visualization or in simple words is signal face. Signal faces comprise of solid red, and green lights. Here in the transmiiting section we are assigned switches in ambulance for east, west, north, and south directions. In this the ambulance driver will press north side direction switch of that case the north side signal indicates green automatically through zigbee communication. Similarly south side ,west side , and east side also follows same process. Zigbee based Ambulance alert system which civilian drivers elect to stay off the road in which the 2 signals automatically falls red and green to ambulance by sending signal from ambulance to traffic light sensor system.
CHAPTER-2
2.1 AT89S52
A BRIEF HISTORY OF 8051
In 1981, Intel Corporation introduced an 8 bit microcontroller called 8051. This microcontroller had 128 bytes of RAM, 4K bytes of chip ROM, two timers, one serial port, and four ports all on a single chip. At the time it was also referred as “A SYSTEM ON A CHIP”
AT89S52:
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 Atmel’s high-density nonvolatile memory technology and is compatible with the industry-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
figure2.1(a) AT89S52 IC
• 8031 has 128 bytes of RAM, two timers and 6 interrupts.
• 8051 has 4K ROM, 128 bytes of RAM, two timers and 6 interrupts.
• 8052 has 8K ROM, 256 bytes of RAM, three timers and 8 interrupts.
Of the three microcontrollers, 8051 is the most preferable. Microcontroller supports both serial and parallel communication.
In the concerned project 8052 microcontroller is used. Here microcontroller used is AT89S52, which is manufactured by ATMEL laboratories.
The 8051 is the name of a big family of microcontrollers. The device which we are going to use along this tutorial is the 'AT89S52' which is a typical 8051 microcontroller manufactured by Atmel™. Note that this part doesn't aim to explain the functioning of the different components of a 89S52 microcontroller, but rather to give you a general idea of the organization of the chip and the available features, which shall be explained in detail along this tutorial.
The block diagram provided by Atmel™ in their datasheet showing the architecture the 89S52 device can seem very complicated, and since we are going to use the C high level language to program it, a simpler architecture can be represented as the figure 1.2.A.
This
Bulky:
On comparing a board full of chips (Microprocessors) with one chip with all components in it (Microcontroller).
Debugging:
Lots of Microprocessor circuitry and program to debug. In Micro controller there is no Microprocessor circuitry to debug.
Slower Development time: As we have observed Microprocessors need a lot of debugging at board level and at program level, where as, Micro controller do not have the excessive circuitry and the built-in peripheral chips are easier to program for operation.
So peripheral devices like Timer/Counter, Parallel programmable port, Serial Communication Port, Interrupt controller and so on, which were most often used were integrated with the Microprocessor to present the Micro controller .RAM and ROM also were integrated in the same chip. The ROM size was anything from 256 bytes to 32Kb or more. RAM was optimized to minimum of 64 bytes to 256 bytes or more.
Microprocessor has following instructions to perform:
1. Reading instructions or data from program memory ROM.
2. Interpreting the instruction and executing it.
3. Microprocessor Program is a collection of instructions stored in a Nonvolatile memory.
4. Read Data from I/O device
5. Process the input read, as per the instructions read in program memory.
6. Read or write data to Data memory.
7. Write data to I/O device and output the result of processing to O/P device.