12-04-2011, 03:43 PM
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ABSTRACT
This system is developed to gather data of atmospheric condition in hazardous/remote areas where human intervention is a risk.
This project is designed using embedded technology. Each day, our lives become more dependent on ’embedded systems’, a digital information technology that is embedded in our environment. It’s rapidly growing industry where growth opportunities are numerous. An embedded system is built to perform its duty , completely or partially independent of human interventions and is specially designed to perform a few tasks in the most efficient way. Embedded systems span all aspects of modern life and there are many examples of their use. The uses of embedded systems are virtually limitless, because every day new products are introduced to the market that utilizes embedded system in novel ways.
Typically, an embedded system is housed on a single microprocessor or microcontroller board with the programs stored in it. Microcontroller is more preferred to microprocessor because it contains all the features of a full computer including central processor, in-built clock circuitry, ROM, RAM, input and output ports with special features such as serial communication, analogue-to-digital conversion etc .
Projects uses microchip’s microcontroller IC named peripheral interface controller (PiC) and Microchip’s ‘integrated Development Environment’, MPLAB, to simulate and assemble the written code.
INTRODUCTION
This project is designed with microcontroller (PIC), LCD, ADC, USART, Zigbee, sensors and visual basic 6.0.The project involves designing and developing a transmitter and receiver section that can be used for data acquisition via ZIGBEE modules. The receiver and transmitter are equipped with microcontroller. At transmitter side there are sensors to sence atmospheric conditions like pressure, temperature, humidity, wind speed, wind direction etc, these sensed signals are inputted to the microcontroller, which triggers the zigbee module to transmit the signals. The receiver captures these signals; microcontroller will decode and analyze it. Thus, the sensed signals will be displayed with the help of a LCD.
A VB interfaced database, connected to microcontroller through RS 232 interface, displays information regarding the person that has been already fed into it. Zigbee is a wireless network used for home, building and industrial control. It conforms to the IEEE802.15.4 wireless standard for low data rate network. With a maximum speed of 250Kbps at 2.4GHz, zigbee is designed for low power so that batteries can last for month and years. The typical Zigbee transmission range is roughly 500 meters.
Features
• Can use hazardous/remote areas where life is at risk.
• Independent of line-of-sight communication.
• Support for multiple network topologies.
• High data reliability.
• Transmission range available up to 1.6 Km
• Low power consumption, with battery life ranging from months to years.
• Highly reliable, cost effective and compact in size.
• Simple to install and easy to maintain.
Block diagram explanation
Transmitter
The block diagram of the transmitting section consists of three sections. The sensors, micro controller and the zigbee module & LCD. In the first section it contains the sensors. Then comes the micro controller section and finally the LCD and the zigbee module.
It is the sensors that collect the parameters to be collected from the external environment. Mainly five sensors are used, air temperature sensor, humidity sensor, light sensor, wind direction sensor and pressure sensor. The data from the sensors is fed to the pic microcontroller, the micro controller has inbuilt ADC. The analog inputs from the sensors is converted to digital values by the analog to digital converters within the controller. The processed signal is now given to the LCD module, which displays the data collected by the sensors. At the same time the processed signal is transmitted to the zigbee module, from where the data get transmitted wirelessly to the receiver section.
Receiver
The datas which are transmitted from the transmitter side through the Zigbee module are received at the receiver circuit through another Zigbee module .The values thus collected are then send to the pic through the inbuilt USART module. Now the pic will transmit it to the LCD and to the PC
EMBEDDED SYSTEM
An embedded system can be described as one consisting of a processor, associated peripherals and software used for a specific purpose. Embedded systems have already improved our lives in numerous ways. A good example is an automatic washing machine or a microwave oven. Embedded system does not require a complete operating system, which may make the system bulky, but only the basic functionalities of an operating system, is needed. All embedded systems not have the same software and hardware, which is why these systems perform, varied task. All embedded systems need microprocessor and the kind of microprocessors used in them are quite varied. Embedded systems have already improved our lives in numerous ways. Such a system is in direct contrast to personal computer, which is not designed to do a specific task. The PC aids us in drafting a letter, in computing at a faster rate, in chatting with friends and so on, but an embedded system is designed to do a specific task with in a given time frame, repeatedly, endlessly with or without human intervention. Unlike a PC, embedded system does not require a complete operating system, which may make the system bulky, but only the basic functionalities of an operating system is needed. Software for the embedded system must handle problems beyond those found in application software for desk computers or mainframe computers. Embedded software often have several things to do at once, respond to external events, cope with unusual conditions without human intervention, while being subjected to deadlines etc. All Embedded systems do not have the same hardware and software, which is why these system perform, varied task. All embedded systems need a microprocessor, and the kinds of microprocessor used in them are quite varied.
