1.INTRODUCTION
Disasters
can disrupt economic and social balance of the society. Because of high rise
buildings and other manmade structures urban and industrial areas are
considered to be more susceptible to disasters. These disasters can be
categorized into natural and human induced disasters. Natural disasters include
floods, storms, cyclones, bush fire, earthquakes etc whereas human induced
disasters include transportation accidents, industrial accidents, major fires
etc.
During
these emergency situations, and especially in urban disaster, in order to
prevent loss of life and property, various essential services (like policeman,
fire fighters and medical assistance etc) are deployed. They need to cooperate
to save lives, protect structural infrastructure, and evacuate victims to
safety. In such situations, human rescuers must make quick decisions under
stress, and try to get victims to safety often at their own risk. They must
gather determine the location and status of victims and the stability of the
structures as quickly as possible so that medics and firefighters can enter the
disaster area and save victims. All of these tasks are performed mostly by
human and trained dogs, often in very dangerous and risky conditions. But the
rescue operations with the help of trained humans or dogs are greatly time
consuming and one can never guarantee the success of such operation. Moreover
there are chances for the loss of lives of
rescuers during such risky and dangerous operations. Due to the above
reasons mobile robots have been proposed to help the rescuers and to perform
tasks that neither humans, dogs nor existing tools can do. Such simulated
robots should have the capability to determine its current location in
real-time and to wirelessly communicate with the rescue team.
Hence in
this project, we focus on a system named as ‘Alive Human Being Detector’ which
will work in disaster environments of manmade structures like collapsed
buildings, war fields etc. It can assist firemen, police, and disaster agencies
with reconnaissance, site evaluation, human detection etc.
The aim of
this work is to provide a low cost, semi-autonomous, heterogeneous, and user
friendly sensor suite for human detection in the disaster environment.
Conditions in a disaster area are extreme with many unknown parameters. Victims
may be covered in debris, trapped in voids, or entombed, making it difficult to
find them and determine their state of health. This is why it will be important
to choose a set of different sensors which are complementary and able to
operate in these conditions.
A rescue robot is a robot that has been designed for the
purpose of aiding rescue workers. Common situations that employ rescue robots
are mining accidents, urban disasters, hostage situations, and explosions.
Rescue robots were used in the search for victims and survivors after the September
11 attacks in New York.The benefits of rescue
robots to these operations include reduced personnel requirements, reduced
fatigue, and access to otherwise unreachable areas.
Our project aims to develop an economic robot, which works
in dtmf technology. It can be used in areas were rescue needed, the robot
senses the temperature and alarm will be produced when it detects alive body
and rescue operation can be done in following areas.
2. SYSTEM FEATURES
2.1
BLOCK DIAGRAM
Fig 2.1.1 Block diagram
2.2 BLOCK DIAGRAM EXPLANATION
The first block is the mobile phone, from which the DTMF technology is
being used. The output of the mobile is given to the DTMF decoder IC MT8870.The
PIC microcontroller used here is 16F873A. Output of the IC is given to the PIC
from where which it goes to the motor driver.L293A is used here. According to
the instructions given through the mobile ,robot can be moved in respective
directions. For temperature sensing LM 35 is used.3 motors are there. A feedback
switch is also provided.
2.2.1
DTMF KEYPAD
The DTMF keypad is laid
out in a 4×4 matrix, with each row representing a low frequency, and each column representing a high frequency. Pressing a single
key (such as '1' ) will send a sinusoidal tone for each of the
two frequencies (697 and 1209 Hertz (Hz)). The original keypads had
levers inside, so each button activated two contacts. The multiple tones are
the reason for calling the system multi frequency. These tones are then decoded
by the switching center to determine which key was pressed.
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DTMF keypad frequencies (with sound clips)
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1209 Hz
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1336 Hz
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1477 Hz
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1633 Hz
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697 Hz
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770 Hz
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852 Hz
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941 Hz
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Table 2.2.1.1 DTMF keypad
2.2.2 DTMF DECODER
This
circuit detects the dial tone from a telephone line and decodes the
keypad pressed on the remote telephone. The dial tone we heard when we pick up
the phone set is call Dual Tone Multi-Frequency, DTMF in short. The name was
given because the tone that we heard over the phone is actually make up of two
distinct frequency tone, hence the name dual tone. The DTMF tone is a form of
one way communication between the dialer and the telephone exchange.
A complete
communication consist of the tone generator and the tone decoder. In this
article, we are use the IC MT8870DE, the main component to decode the input
dial tone to 5 digital output. These digital bits can be interface to a
computer or microcontroller for further application (eg. remote control, phone
line transfer operation, etc...).
Detection
of dial tones is reflected on the bit TOE, while the output Q4, Q3, Q2, Q1
indicate the dial tone that is being detected on the telephony system. A
complete table of the decoded digital output for individual dial tone is
available in the coming section.
2.2.3 PIC
MICROCONTROLLER
The PIC
microcontroller family is manufactured by Microchip Technology Inc. Currently
they are one of the most popular microcontrollers, used in many commercial and
industrial applications. Over 120 million devices are sold each year. The
programmability and the versatile applications for which a PIC microcontroller
can be used have made it a first choice in small scale applications and project
work.
The PIC
microcontroller architecture is based on a modified Harvard RISC (Reduced
Instruction set Computer) instruction set with dual-bus architecture, providing
fast and flexible design with an easy migration path from only 6 pins to 80
pins, and from 384 bytes to 128 kilobytes of program memory.
PIC microcontrollers are available
with different specifications depending on:
• Memory Type
– Flash
– OTP (One-time-programmable)
– ROM (Read-only-memory)
– ROM less
• Input–Output (I/O) Pin Count
– 4–18 pins
– 20–28 pins
– 32–44 pins
– 45 and above pins
• Memory Size
– 0.5–1 K
– 2–4 K
– 8–16 K
– 24–32 K
– 48–64 K
All PIC
microcontrollers offer the following features
•
RISC instruction set with only handful of instructions to
learn
•
Digital I/O
•
On chip timer
•
Power-on-reset
Power-saving
sleep mode
•
High source and sink current
•
Direct indirect and relative addressing modes
•
External clock interface
•
RAM data memory
•
EPROM or flash
program memory
Some
devices offer the following additional features
•
Analog input channel
•
Analog comparators
•
Additional timer circuit
•
EEPROM data memory
•
External and internal interrupts
•
Internal oscillator
•
PWM output
•
USART serial interface.
Fig:2.2.3.1 PIC 16F873
2.2.4
MOTOR DRIVER
To rotate the motor as per human instructions we have to interface the
motor with a microcontroller. But the output current of microcontroller is not
sufficient to drive a dc motor. So we use motor drivers. Usually H bridge is
preferred way of interfacing a DC motor.
L293D is a
dual H bridge motor driver. The name "H
Bridge" is derived from the actual shape of the switching circuit which
controls the motion of the motor. It is also known as "Full Bridge".
Basically there are four switching elements in the H Bridge as shown in the
figure below named as "High side left", "High side right",
"Low side right", "Low side left". When these switches are
turned on in pairs motor changes its direction accordingly. Like, if we switch
on High side left and Low side right then motor rotate in forward direction, as
current flows from power supply through the motor coil goes to ground via
switch low side right. Similarly, when we switch on low side left and high side
right, the current flows in opposite direction and motor rotates in backward
direction. This is the basic working of HBridge.
Fig
2.2.4.1 L293D MOTOR DRIVER
•
2.2.5
TEMPERATURE SENSOR-LM35
A sensor can be
regarded as a transducer which can convert one form of energy in to another
form. It can be used to sense the vital signs parameter for checking whether a
person is alive or not. Body temperature is one of the most important vital
sign parameter which can give information about the condition of a person. So
here we use sensor to sense the body temperature. Temperature sensors consist
of temperature sensitive resistors whose resistance vary with temperature. Hence
such devices can produce output voltages that are proportional to the
temperature. This sensor output is processed by the microcontroller .LM35 is a
commonly available temperature sensor having positive temperature coefficient
of resistance. i.e., the output voltage of the sensor increases with
temperature.
Fig 2.2.5.1 LM35
2.2.6 WIRELESS CAMERA
Wireless
security cameras are Closed Circuit Television (CCTV) cameras that transmit a video and audio signal to a wireless
receiver through a radio band. Many wireless security cameras require at least
one cable or wire for power; "wireless" refers to the transmission of
video/audio. However, some wireless security cameras are battery-powered,
making the cameras truly wireless from top to bottom. Wireless cameras are
proving very popular among modern security consumers due to their low
installation costs (there is no need to run expensive video extension cables)
and flexible mounting options; wireless cameras can be mounted/installed in
locations previously unavailable to standard wired cameras.
Fig
2.2.6.1 Wireless camera
Wireless security cameras function best when there
is a clear line of sight between the camera(s) and the receiver. Outdoors, and
with clear line of sight, digital wireless cameras typically have a range
between 250 to 450 feet. Indoors, the range can be limited to 100 to 150 feet.
The signal range varies depending on the type of building materials and/or
objects the wireless signal must pass through.
2.2.7
ALARM
The alarm will be activated if and only if the human body is
alive.
.
3. HARDWARE IMPLEMENTATION
3.1
CIRCUIT DIAGRAM
fig3.1.1 circuit diagram
3.2 CIRCUIT EXPLANATION
3.2.1 DTMF SECTION
The very first section is the DTMF section.DTMF can be
expanded as Dual Tone Multi Frequency.Every key in the mobile phone keypad has
a particular frequency associated with it,which is the combination of an upper
frequency(coloum) and a lower frequency(row).When a particular key is pressed a
combinatinl frequency arrives at the input of the decoder.
WORKING
The
combinational frequency that arrives at the input of the DTMF decoder IC will
be decoded into four output bits.The strobe pin of the decoder IC will be high
if and only if there is a signal at its input.Tho output bits are available as
Q3,Q2,Q1,Q0.The output of the decoder is given to port C of
microcontroller.PIC16F873A is the microcontroller used here.It is a 28 pin
package IC,which has 3 ports and all the 3 ports are being used here.Port A is
the input port.To this port the temperature sensor is connected.Port B is the
output port.Connections to the motor drivers are done from this port.These
motor drivers drive three gear motors which work on a power supply of 6volts.Two
of these act as whels of the robot and the other one is for controlling
the movement of arm that holds the
temperature sensor.
As
a whole the robot’s movement is controlled with the key pressed on mobile
phone.The path covered by the robot is viewed in a PC using a wireless
camera.Temperature sensor senses the temperature of the victim and it will be
compared with the already set reference temperature of the pic.If the measured
temperature is greater than the
reference temperature alarm will be activated, indicating that detected body is
alive.
4.
SOFTWARE DEVELOPMENT
4.1 FLOW CHART
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4.3 ALGORITHM
·
STEP 1: START
·
STEP2: INITIALISE VARIABLES
·
STEP3: CHECK IF DTMF DATA IS AVAILABLE
o
IF NO RECHECK,
o
IF YES GOTO STEP4
·
STEP4 :IF DTMF DATA=2, MOVE FORWARD
o
IF DTMF DATA=8, MOVE BACKWARD
o
IF DTMF DATA=4, TURN LEFT
o
IF DTMF DATA=6,TURN RIGHT
o
IF DTMF DATA=#, STOP
o
IF DTMF DATA =5,ARM DOWN—SENSE TEMP
·
STEP5: IF TEMP>SET TEMP----ALARM
ACTIVATED
o
ELSE ARM UP…GOTO STEP 3
4.3 SOFTWARE TOOLS
4.3.1
MICROCHIP TECHNOLOGY
Microchip Technology (NASDAQ: MCHP) is an American
manufacturer of microcontroller, memory and analog semiconductors. Its products
include microcontrollers (PICmicro, dsPIC / PIC24, PIC32), Serial EEPROM
devices, Serial SRAM devices, KEELOQ devices, radio frequency (RF) devices,
thermal, power and battery management analog devices, as well as linear,
interface and mixed signal devices. Some of the interface devices include USB,
ZigBee/MiWi, Controller Area Network, and Ethernet.
Corporate headquarters is located at Chandler, Arizona with
wafer fabs in Tempe, Arizona and Gresham, Oregon.Among its chief competitors
are Analog Devices, Atmel, Freescale, Infineon, Maxim Integrated Products, NXP
Semiconductors, Renesas Electronics, STMicroelectronics, and Texas Instruments
4.3.2
EMBEDDED C
Embedded C is a set of language extensions for
the C Programming language by
the C Standards committee to
address commonality issues that exist between C extensions for different embedded systems. Historically, embedded C
programming requires nonstandard extensions to the C language in order to
support exotic features such as fixed-point arithmetic, multiple
distinct memory banks, and
basic I/O operations.
In 2008, the C Standards Committee extended the C language
to address these issues by providing a common standard for all implementations
to adhere to. It includes a number of features not available in normal C, such
as, fixed-point arithmetic, named address spaces, and basic I/O hardware
addressing
5. PCB
DESIGN
A printed circuit board, or PCB, is used to
mechanically support and electrically connect electronic components using
conductive pathways, tracks or signal traces etched from copper
sheets laminated onto a non-conductive substrate. It is also referred
to as printed wiring board (PWB) or etched wiring board. A PCB populated
with electronic components is a printed circuit assembly (PCA), also known
as a printed circuit board assembly (PCBA).
Printed circuit boards are used in virtually all but the
simplest commercially-produced electronic devices. PCBs are inexpensive, and
can be highly reliable. They require much more layout effort and higher initial
cost than either wire wrap construction, but are much cheaper and faster for
high-volume production; the production and soldering of PCBs can be done by
totally automated equipment. Much of the electronics industry's PCB design,
assembly, and quality control needs are set by standards that are published by
the IPC organization.
Conducting layers are typically made of thin copper foil.
Insulating layers dielectric is typically laminated together
with epoxy prepreg. The board is typically coated with a solder mask that
is green in color. Other colors that are normally available are blue, black,
white and red. There are quite a few different dielectrics that can be chosen
to provide different insulating values depending on the requirements of the
circuit. FR-4 is by far the most common material used today. The board with
copper on it is called "copper-clad laminate".
PATTERNING
(ETCHING)
The vast majority of printed circuit boards are made by
bonding a layer of copper over the entire substrate, sometimes on both sides,
(creating a "blank PCB") then removing unwanted copper after applying
a temporary mask (e.g. by etching), leaving only the desired copper traces. A
few PCBs are made by adding traces to the bare substrate (or a
substrate with a very thin layer of copper) usually by a complex process
of
multiple electroplating steps. The PCB manufacturing method
primarily depends on whether it is for production volume or sample/prototype
quantities.
The dimensions of the copper conductors of the printed
circuit board are related to the amount of current the conductor must carry.
Each trace consists of a flat, narrow part of the copper foil that remains
after etching. Signal traces are usually narrower than power or ground traces
because their current carrying requirements are usually much less. In a
multi-layer board one entire layer may be mostly solid copper to act as a
ground plane for shielding and power return. For printed circuit boards that
contain microwave circuits, transmission lines can be laid out in the form of
strip line and micro strip with carefully-controlled dimensions to assure
consistent impedance. In radio-frequency circuits the inductance and
capacitance of the printed circuit board conductors can be used as a deliberate
part of the circuit design, obviating the need for additional discrete
components.
ETCHING
Chemical etching is done with ferric chloride, ammonium
persulfate, or sometimes hydrochloric acid. For PTH (plated-through holes),
additional steps of electrolysis deposition are done after the holes are
drilled, then copper is electroplated to build up the thickness, the boards are
screened, and plated with tin/lead. The tin/lead becomes the resist leaving the
bare copper to be etched away.
LAMINATION
Some PCBs have trace layers inside the PCB and are called
multi-layer PCBs. These are formed by bonding together separately etched thin
boards.
DRILLING
Holes
through a PCB are typically drilled with tiny drill bits made of solid tungsten
carbide. The drilling is performed by automated drilling machines with
placement controlled by a drill tape or drill file. These computer-generated
files are also called numerically controlled drill (NCD) files or
"Excellon files". The drill file describes the location and size of
each drilled hole. These holes are often filled with annular rings (hollow
rivets) to create vias. Vias allow the electrical and thermal connection of
conductors on opposite sides of the PCB.
5.1 PCB DESIGN AND
FABRICATION
Designing of a PCB is a major slip in the
production of PCBs. It forms a distinct factor n electronic performance and
reliability. The productivity of a PCB with assembly and serviceability also
depends on design.
STEPS INVOLVED
1. Prepare the required circuit diagram
2. List out the components, their sizes
etc.
3. Draft it onto a graph sheet
4. Place all pads and finish thin tracks
5. Put it on the mylor sheet and then on
the graph sheet
6. Place parts including screw holes with
the help of knife.
7. Fix all the tracks.
8. Keep one component as the key.
CONVERSION OF CIRCUIT DIAGRAM
1. Cutting lines, mounting lines are done
2. List all the components their length diameter
thickness code names etc.
3. Keep one component as key component
4. Keep key component first and their
supporting tools
5. All tracks are straight lines
6. In between ICs no signal lines should
be passed
7. Mark the pin number of IC on the lay
out for avoiding dislocations
8. The length of the conductor should be
as low as possible
9. Place all the components, resistors,
diodes etc. parallel to each other
LAY OUT APPROACHES
First
the board outlines and the connectors are marked on a sheet of paper followed
by sketching of the component outlines with connecting point and conductor
patterns. Prepare the layout as viewed from the component side first, so as to
avoid any confusion. The layout is developed in the direction of signal flow as
far as possible. Among
the components the larger ones are filled first and the space between is filled
with smaller ones. Components, rewiring input, output connections came near the
connectors. All
the components are placed in such a manner that de-soldering of the component
is not is not necessary, if they have to be re placed. While designing the
conductors, the minimum spacing requirement for the final network should be
known. Transforming the lay
out to copper. The
lay out made on the graph sheet should be redrawn on the copper clad using
paint or nail polish.
ETCHING
The
final copper pattern is formed by selective removal of the unwanted copper
which is not protected by an electric rebist. FeCl3 solution is popularly used
etching solution. FeCl3 powder is made into a solution using water and kept in
a plastic tray. Immerse the marked copper clad in this solution for two or
three hours. Due to the reaction solution will became weak and it is not
recommended for further etching process. Take out the etched sheet from the
tray and dry out for in sunlight for an hour.
ETCHANTS
Many
factors have to be considered to choose the most suitable etchant system for a
PCB process. Some commonly used etchants are FeCl3, Cupric chloride, Chromic
acid etc. After etching FeCl3 is washed from the board and cleaned dry. Paint
is removed using suitable from the component insertion. Holes are drilled into
appropriate position and the components are soldered into PCB carefully.
Take
a copper clad of the required dimensions. Transfer the circuit layout to the
copper clad using cotton paper. The layout area should be marked with nail
polish. Put the copper clad into FeCl3 solution and warm it. Stage by stage
transformation of the copper clad occurs. Warm the solution intermittently
according to the requirement. After about 4 hours etching will be completed.
Wash the board using soap solution to remove the remaining of FeCl3 solution.
Scrap off the nail polish and drill holes wherever required using appropriate
drill bits. PCB is fabricated.
5.2 PCB
LAYOUT
Fig:5.3.1 PCB LAYOUT
5.3
COMPONENT LAYOUT
Fig5.4.2 COMPONENT LAYOUT
6. ADVANTAGES AND DISADVANTAGES
6.1
ADVANTAGES
•
Economic
•
Fast
•
Reliable
•
Semi autonomous
•
User friendly
•
Adaptable
6.2
DISADVANTAGES
•
Night time work difficult
•
Range limitations
7. APPLICATION AND FUTURE ENHANCEMENT
Alive Human Being Detector finds
applications mainly in disaster management and crisis management. Some of its
major applications are listed below.
•
In military applications to detect the presence of human
being.
•
In Rescue operations where human reach is impossible.
•
In Disaster management
•
In Crisis management
•
This equipment can be used at mines, earthquake prone places
•
In Medical field
IN FUTURE:
•
Include flying options in robot
•
Make the robotic arm capable of up/down movement
•
Modify its shape to pass through complex environments or to
climb some obstacles.
•
Include sensors to sense more vital sign parameters such as
heart beat, ECG, EEG, eyeball movement etc.
•
Make the robot capable of carrying the victim to secure
places.
•
Include metal detectors and bomb sensors to detect the
presence of bomb in Warfield and in rescue operations.
•
Include proper lighting options for night time usage.
8. CONCLUSION
Alive
Human Being Detector is an autonomous robot for detecting alive humans in
destructed environments. This Alive human body detection system uses
temperature sensor, mobile phone,
wireless camera and PIC microcontroller to transmit and analyze conditions
of human body. The task of identifying human being in rescue operations is
difficult for the human agent but it is simple for the robotic agent. In order
to detect a human body, an autonomous robot must be equipped with a specific
set of sensors that provide information about the presence of a person in the
environment around. This system uses a temperature sensor in order to detect
the existence of living humans and a low cost camera in order to acquire a
video of the scene as needed. The wireless camera shows the path moved by the
robot that is displayed on a laptop at the control section. This approach
requires a relatively small number of data to be acquired and processed during
the rescue operation. This way, the real-time cost of processing and data
transmission is considerably reduced. This system has the potential to achieve
high performance in detecting alive humans in devastated environments
relatively quickly and cost-effectively.
The future
work would be to improve detection using more reliable sensors and to modify
its shape to pass through complex environments or to climb some obstacles. To
have a better quality of human detection, it would be a good solution to add a
long distance sensor. Finally, the most challenging part would be to maximize
the autonomy of the robot to limit user attention to it.
TEST RESULT
Alive Human Being Detector based on
DTMF technology was developed and alive human victims were detected with the
simple temperature sensor IC.
9.REFERENCES
— William stallings,”wireless communication and
networking”,PRENTICE-HALL of India Pvt.Ltd
— Dreamtech software team “Programming for Embedded System”
