24-12-2010, 03:36 PM
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ABSTRACT
“Thousands of persons killed as a cause of earthquake”. The above words aren’t the headlines of the newspaper but daily news everyone come across whenever we go through a newspaper or watching over a TV news.
A person’s life is precious and meaningful to his loved ones.
We, as responsible Engineers felt a part of society to bring a system to avoid these mishaps. With the meteoric Embedded systems along with microprocessor our designed system in preventing deaths and providing safe guided measures.
A new revolutionary microwave life detection system, which is used to locate human beings buried under earthquake rubble, has been designed. This system operating at certain frequency can remotely detect the breathing and heartbeat signals of human beings buried under earthquake rubble. By proper processing of these signals, the status of the person under trap can be easily judged. The entire process takes place within a few seconds as the system is controlled by a microprocessor (8085) or microcontroller unit.
By advent of this system the world death rate may decrease to greater extent as large percentage of death occur due to earthquake.
We welcome and wish you to a safe journey of this paper.
INTRODUCTION:
At present as we all know the need of the hour is to find an effective method for rescuing people buried under earthquake rubble (or) collapsed building. It has to be done before we experience another quake. Present methods for searching and rescuing victims buried (or) tapped under earthquake rubble are not effective. Taking all the factors in mind, a system, which will be really effective to solve the problem, has been designed.
PRINCIPLE OF OPERATION:
The basic principle is that when a microwave beam of certain frequency [L (or) S band (or) UHF band] is aimed at a portion of rubble (or) collapsed building under which a person has been trapped, the microwave beam can penetrate through the rubble to reach the person.
When the microwave beam focuses the person, the reflected wave from the person’s body will be modulated (or) changed by his/her movements, which include breathing and heartbeat. Simultaneously, reflected waves are also received from the collapsed structures.
So, if the reflected waves from the immovable debris are cancelled and the reflected wave from the person’s body is properly distinguished, the breathing and heartbeat signals can be detected.
By proper processing of these signals, the status of the person under trap can be easily judged. Thus a person under debris can be identified.
MAJOR COMPONENTS OF THE CIRCUIT:
The microwave life detection system has four major components. They are
1. A microwave circuit which generates, amplifies and distributes microwave signals to different microwave components.
2. A microwave controlled clutter cancellation system, which creates an optimal signal to cancel the clutter from the rubble.
3. A dual antenna system, which consists of two antennas, energized sequentially.
4. A laptop computer which controls the microprocessor and acts as the monitor for the output signal.
WORKING FREQUENCY:
The frequency of the microwave falls under two categories, depending on the type and nature of the collapsed building. They are
1. L (or) S band frequency say 1150 MHz
2. UHF band frequency say 450 MHz
Let us see the advantages and disadvantages of both the systems later.
CIRCUIT DESCRIPTION:
The circuit description is as follows:
Phase locked oscillator:
The phase locked oscillator generates a very stable electromagnetic wave say 1150 MHz with output power say 400mW.
Directional coupler 1 (10 dB):
This wave is then fed through a 10 dB directional coupler and a circulator before reaching a radio frequency switch, which energizes the dual antenna system. Also the ten dB directional coupler branches out one-tenth of the wave (40mW) which is then divided equally by a directional coupler 2 (3 dB).
Directional coupler 2 (3 dB):
One output of the 3 dB directional coupler 2 (20mW) drives the clutter cancellation unit. Other output (20mW) serves as a local reference signal for the double balanced mixer.
Antenna system:
The dual antenna system has two antennas, which are energized sequentially by an electronic switch. Each antenna acts separately.
Clutter cancellation system:
The clutter cancellation unit consists of
1. A digitally controlled phase shifter I
2. A fixed attenuator
3. A RF amplifier
4. A digitally controlled attenuator.
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Presented by :
Pratik Mehta
Pratik Mehta
Possible within few couples of years.
Real Time Operating System (RTOS) and Embedded system are the major technologies that played a major role in making the above fairly tales come true.
Defination of Embedded System
An embedded system is one that has computer hardware with software embedded in it as one of its most important component.
It is a dedicated computer based system for an application or product.
As its software usually embeds in ROM, it does not need secondary memories as in a computer.
