A
Technical seminar Report
On
Embedded Systems
“A New Revolutionary System To Detect Human Beings Trapped Under Earthquake Rubble”
SUBMITTEd BY
V.Vishal (08841a04a7)
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
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.
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 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 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.
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.
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 1300MHz (23-centimeter band). The L band refers to the frequency range of 950 MHz to 1450 MHz.
The S band ranges from 2 to 4GHz, crossing the conventional boundary between UHF and SHF at 3.0GHz. 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 5.2GHz.
Ultra high frequency (UHF) designates a range of electromagnetic waves with frequencies between 300 MHz and 3 GHz (3,000MHz), also known as the decimeter band or decimeter wave as the wavelengths range from one to ten decimeters (10cm 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 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.
· 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 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.
8: MICROPROCESSOR:
Ø 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
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.