A

TECHNICAL SEMINAR REPORT

ON

EMBEDDED SYSTEMS

“A NEW REVOLUTIONARY SYSTEM TO DETECT HUMAN BEINGS TRAPPED UNDER EARTHQUAKE

RUBBLE”

SUBMITTED BY

V.VISHAL (08841A04A7)

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CONTENTS

Topic Pg.No

1: ABSTRACT 3

2: INTRODUCTION 4

3: PRINCIPLE OF OPERATION 6

4: MAJOR COMPONENTS OF THE CIRCUIT 7

5: WORKING FREQUENCY 8

6: CIRCUIT DESCRIPTION 9

7: WORKING 10

8: MICROPROCESSOR 12

9: FLOW CHART FOR ANTENNA SYSTEM 19

10: FLOW CHART FOR CLUTTER CANCELLATION SYSTEM 20

11: HIGHLIGHTS 21

12: CONCLUSION 22

13: REFERENCES 22

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1. ABSTRACT

“Thousands of persons killed as a cause of earthquake”. The above words aren’t the

headlines of the newspaper but news everyone come across whenever we go through a

newspaper or watching over a TV news at some particular day. 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 is used 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.

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2: 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.

The term embedded system is quite a complex one. Simply it is a combination of

hardware and software that forms the component of a larger system; this in turn is

programmed to perform a range of dedicated functions usually with a minimal operator

intervention. In embedded systems the hardware is normally unique to a given application;

computer chips are embedded into the control electronics to manage the products

functionality.

Embedded systems are rapidly becoming a catalyst for change in computing data

communications, telecommunications, industrial control and entertainment sectors. New

innovative applications in these as well as other areas such as home networking and car

infotainment will roll out in the near feature.

In present Arena every thing is going compact and adaptable. More over continuing

trends in Microelectronic Technology and its integration begins to alter the ground rules in the

design of high performance systems, such as Embedded Systems. Those Embedded Systems

and Real Time Operating Systems (RTOS) are part-achieving, ubiquity, blurring the lines

between science fiction and hard reality The main idea behind these Embedded Systems is

“why to use a hammer when a gentle touch would do”.

Embedded Systems exists in wide variety of fields from automated vending machine to

complex embedded systems that controls aircraft functions. This paper mainly contains the

design concepts; development process of Embedded Systems and the Hardware architecture

containing processor, Memory and other Hardware devices has been discussed briefly. Recent

trends, applications and the explanation developing this embedded system technology. This

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Embedded System technology may one day result in such a comfort for human, so that he

could live in an intelligent home and make his health undisturbed Embedded Systems are

combinations of hardware and software that are mounted on compact electronic circuit boards

integrated into the devices. They are engineered or intended to perform one specific function

in a specific environment.

An embedded system is a special-purpose computer system built into a larger device,

typically required to meet very different requirements than a general-purpose personal

computers. Programs on an embedded system often must run with real-time constraints. Real-

time computing is that type of computing in which correctness of the system not only depends

on logical result of computation but also on the time at which the results are produced. Usually

there is no disk drive, operating system, keyboard or screen in an embedded system. Most

embedded systems are small enough to sit on the end of a thumb and are usually hidden within

much larger and more complex mobile computing or electronic devices, so they often go

unnoticed. But embedded systems actually represent the vast majority of semiconductor sales.

According to an estimate, there are 5 billion embedded microprocessors in use today.

Design of embedded systems:

One important decision in the design of an embedded system is the selection of the

processor(s) around which the rest of the system is to be built. The electronics usually uses

either a microprocessor or a micro controller. Some large or old systems use general-purpose

mainframe computers or minicomputers

Embedded Processor:

An Embedded Processors is simply a microprocessor that has been “Embedded” into a

device. It is software programmable but interacts with different pieces of hardware and

performs both control and computation. It gives more performance than a micro controller but 5

not as much performance as a general purpose processor. They are used in cars, phones, media

devices, wireless, and printers

Technology:

There are many new technologies being implemented for the designing of the

embedded systems.

Processor technology: It is the architecture of the computation engine used to

implement a system’s desired technology. Processors vary in their customization. They need

not have to be programmable.

I.C. Technology: It’s the manner in which a digital (gate-level) implementation is

mapped onto an IC. IC technologies differ in their customization to a design and with respect to

who builds each layer IC’s consist of numerous layers (perhaps 10 or more) Types are: Full-

custom/VLSI, Semi-custom ASIC (gate array and standard cell), PLD (Programmable Logic

Device).

Design Technology:The manner in which we convert our concept of desired system

functionality into an implementation

3: 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.

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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.

4: 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.

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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.

5: 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

The IEEE L band (20-cm radar long-band) is a portion of the microwave band of the

electromagnetic spectrum ranging roughly from 1 to 2 GHz. It is used by some

communications satellites, and for some terrestrial Eureka 147 digital audio broadcasting

(DAB). The amateur radio service also has an allocation between 1240 and 1300 MHz (23-

centimeter band). The L band refers to the frequency range of 950 MHz to 1450 MHz.

The S band ranges from 2 to 4 GHz, crossing the conventional boundary between UHF

and SHF at 3.0 GHz. It is part of the microwave band of the electromagnetic spectrum. The S

band is used by weather radar, surface ship radar, and some communications satellites,

especially those used by NASA to communicate with the Space Shuttle and the International

Space Station. The 10-cm radar short-band ranges roughly from 1.55 to 5.2 GHz.

Ultra high frequency (UHF) designates a range of electromagnetic waves with

frequencies between 300 MHz and 3 GHz (3,000 MHz), also known as the decimeter band

or decimeter wave as the wavelengths range from one to ten decimeters (10 cm to 1

meter). Radio waves with frequencies above the UHF band fall into the SHF (super high

frequency) and EHF (extremely high frequency) bands, all of which fall into the microwave

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frequency range. Lower frequency signals fall into the VHF (very high frequency) or lower

bands

Let us see the advantages and disadvantages of both the systems later.

6: 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 10 dB

directional coupler branches out one-tenth of the wave (40mW) which is then divided equally

by a directional coupler 2 (3 dB).

Directional couplers are passive devices used in the field of radio technology. They

couple part of the transmission power in a transmission line by a known amount out through

another port, often by using two transmission lines set close enough together such that energy

passing through one is coupled to the other.

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.

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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.

7: WORKING:

Basically the block diagram of microwave life detection system has four major

components. They are A microwave circuit which generates amplifies and distributes

microwave signals to different microwave components. A microwave controlled clutter

cancellation system, which creates an optimal signal to cancel the clutter from the

rubble. A dual antenna system, which consists of two antennas, energized sequentially.

A laptop computer which controls the microprocessor and acts as the monitor for the

output signal.

The wave radiated by the antenna I penetrates the earthquake rubble to reach

the buried person. The reflected wave received by the antenna 2 consists of a large

reflected wave from the rubble and a small reflected wave from the person’s body. The

large clutter from the rubble can be cancelled by a clutter canceling signal. The small

reflected wave from the person’s body couldn’t be cancelled by a pure sinusoidal

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canceling because his/her movements modulate it. The output of the clutter

cancellation circuit is automatically adjusted to be of equal amplitude and opposite

phase as that of the clutter from the rubble. Thus, when the output of the clutter

cancellation circuit is combined with the directional coupler 3 (3 dB), the large clutter

from the rubble is completely cancelled. Now, the output of the directional coupler 3 (3

dB) is passed through a directional coupler 4 (6dB).

One-fourth of the output directed is amplified by a RF pre-amplifier and then mixed with

a local reference signal in a double balanced mixer. Three-fourth of the output is

directed by a microwave detector to provide dc output, which serves as the indicator for

the degree of the clutter cancellation.

When the settings of the digitally controlled phase shifter and the attenuator are

swept the Microprocessor control system, the output of the microwave detector varies

accordingly. At the double balanced mixer, the amplified signal of the reflected wave

from the person’s body is mixed with the local reference signal. The phase of the local

reference signal is controlled by another digitally controlled phase shifter 2 for an

optimal output from the mixer. The output of the mixer consists of the breathing and

heartbeat signals of the human plus some avoidable noise. This output is fed through

a low frequency amplifier and a band pass filter (0.4 Hz) before is played on the monitor.

The function of the digitally controlled phase shifter 2 is to control the phase of the local

reference signal for the purpose of increasing the system sensitivity. The reflected signal

from the person’s body after amplification by the pre-amplifier is mixed with the local

reference signal in a double balanced mixer.

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8: MICROPROCESSOR:

CONTROL UNIT:

The algorithm and flowcharts for the antenna system and the clutter cancellation

system are as follows:

Antenna system:

1. Initially the switch is kept in position 1 (si

BLOCK DIAGRAM

Fig: Life Detection System

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Clutter Cancellation Of The Received Signal:

The wave radiated by the antenna I penetrates the earthquake rubble to reach the

buried person.

The reflected wave received by the antenna 2 consists of a large reflected wave from

the rubble and a small reflected wave from the person’s body.

The large clutter from the rubble can be cancelled by a clutter canceling signal.

The small reflected wave from the person’s body couldn’t be cancelled by a pure

sinusoidal canceling because his/her movements modulate it.

The output of the clutter cancellation circuit is automatically adjusted to be of equal

amplitude and opposite phase as that of the clutter from the rubble.

Thus, when the output of the clutter cancellation circuit is combined with the directional

coupler 3 (3 dB), the large clutter from the rubble is completely cancelled.

Now, the output of the directional coupler 3 (3 dB) is passed through a directional

coupler 4 (6dB).

One-fourth of the output directed is amplified by a RF pre-amplifier and then mixed with

a local reference signal in a double balanced mixer.

Three-fourth of the output is directed by a microwave detector to provide dc output,

which serves as the indicator for the degree of the clutter cancellation.

When the settings of the digitally controlled phase shifter and the attenuator are swept

the

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Microprocessor control system, the output of the microwave detector varies

accordingly.

Demodulation Of The Clutter Cancelled Signal:

At the double balanced mixer, the amplified signal of the reflected wave from the

person’s body is mixed with the local reference signal.

The phase of the local reference signal is controlled by another digitally controlled phase

shifter 2 for an optimal output from the mixer.

The output of the mixer consists of the breathing and heartbeat signals of the human

plus some avoidable noise.

This output is fed through a low frequency amplifier and a band pass filter (0.4 Hz)

before is played on the monitor.

The function of the digitally controlled phase shifter 2 is to control the phase of the local

reference signal for the purpose of increasing the system sensitivity.

The reflected signal from the person’s body after amplification by the pre-amplifier is

mixed with the local reference signal in a double balanced mixer.

Why we need a microprocessor/controller:

The microprocessor is the core of computer systems.

Nowadays many communications, digital entertainment, portable devices, are

controlled by them.

A designer should know what types of components he needs, ways to reduce production costs and product reliable.

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Different aspects of a microprocessor/controller:

Hardware :Interface to the real world

Software :order how to deal with inputs

The necessary tools for a microprocessor/controller:

CPU: Central Processing Unit

I/O: Input /Output

Bus: Address bus & Data bus

Memory: RAM & ROM

Timer

Interrupt

Serial Port

Parallel port

General-purpose microprocessor

CPU for Computers

No RAM, ROM, I/O on CPU chip itself

Example: Intel’s x86, Motorola’s 680x0

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General purpose microprocessor system:

MICROCONTROLLER:

A smaller computer

On-chip RAM, ROM, I/O ports...

Example: Motorola’s 6811, Intel’s 8051, Zilog’s Z8 and PI

A single chip microcontroller:

CPU RAM ROM

I/O PORT TIMER SERIAL

COM PORT

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MICROPROCESSOR VS. MICROCONTROLLER

Microprocessor

CPU is stand-alone, RAM, ROM, I/O, timer are separate

Designer can decide on the amount of ROM, RAM and I/O ports.

expansive

versatility

general-purpos

Microcontroller

• CPU, RAM, ROM, I/O and timer are all on a single chip

• fix amount of on-chip ROM, RAM, I/O ports

• for applications in which cost, power and space are critical

• single-purpose

THREE CRITERIA IN CHOOSING A MICROCONTROLLER:

1. Meeting the computing needs of the task efficiently and cost effectively

• speed, the amount of ROM and RAM, the number of I/O ports and timers, size,

packaging, power consumption

• easy to upgrade

• cost per unit

2. Availability of software development tools

• assemblers, debuggers, C compilers, emulator, simulator, technical support

3. Wide availability and reliable sources of the microcontrollers.

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CONTROL UNIT:

The algorithm and flowcharts for the antenna system and the clutter cancellation

system are as follows:

Antenna system:

2. Initially the switch is kept in position 1 (signal is transmitted through the antenna 1)

3. Wait for some predetermined sending time, Ts

4. Then the switch is thrown to position 2 (signal is received through the antenna 2)

5. Wait for some predetermined receiving time, Tr

6. Go to step 1

7. Repeat the above procedure for some predetermined time, T.

Clutter cancellation system:

1. Send the signal to the rubble through antenna 1.

2. Receive the signal from the rubble through antenna 2.

3. Check the detector output. If it is within the predetermined limits go to step 5.

4. Otherwise send the correction signal to the digitally controlled phase shifter 1

and attenuator and go to step 1.

5. Check the sensitivity of the mixer. If the optimum go to step 7.

6. Otherwise send the correction signal to the digitally controlled phase shifter 2 to

change the phase and go to step 1.

7. Process the signal and send it to the laptop.

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9: FLOW CHART FOR ANTENNA SYSTEM

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10: FLOW CHART FOR CLUTTER CANCELLATION SYSTEM

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ADVANTAGES OF L (OR) S BAND FREQUENCY SYSTEM:

Microwaves of L (or) S band frequency can penetrate the rubble with metallic mesh

easier than that of UHF band frequency waves.

ADVANTAGES OF UHF BAND FREQUENCY SYSTEM:

Microwaves of UHF band frequency can penetrate deeper in rubble (without metallic

mesh) than that of L (or) S band frequency waves.

FREQUENCY RANGE OF BREATHING AND HEARTBEAT SIGNAL:

The frequency range of heartbeat and breathing signals of human beings lies between

0.2 and 3 Hz.

11: HIGHLIGHTS:

1. The location of the person under the rubble can be known by calculating the time lapse

between the sending times, Ts and receiving time, Tr.

2. Since it will not be possible to continuously watch the system under critical situations,

an alarm system has been set, so that whenever the laptop computer system processes

the received signal and identifies that there is a human being, the alarm sound starts.

3. Also under critical situations, where living beings other than humans are not required to

be found out, the system can detect the signals of other living beings based on the

frequency of the breathing and heartbeat signals.

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12: CONCLUSION:

Thus a new sensitive life detection system using microwave radiation for locating human

beings buried under earthquake rubble (or) hidden behind various barriers has been designed.

This system operating either at L (or) S band, UHF band can detect the breathing and heartbeat

signals of human beings buried under earthquake rubble.

13: REFERENCES:

1. Fery, AH.1963.Some effect on human subjects of ultra high frequency radiation

2. Physics of Microwaves (a collection of reports issued under aegis of ministry of scientific

& technical policy of Russian federation)

3. http://grouper.ieee.org/groups/scc28/sc4/Human%20Perception%20FINAL.pdf

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