DETECTOBOT

War Tank Wireless Navigation Control

1

DETECTOBOTThe report submitted to JNTUH in partial fulfilment of the

Requirements for the award of the degree of

BACHELOR OF TECHNOLOGY

In

MECHANICAL ENGINEERING

Submitted by

Md Hasan Ali (10N91A0331) Md Abdul Akheel (10N91A0330)

Syed Mobeenoddin (10N91A0357)

Syed Raufuddin (10N91A0335) Md Umair Ahmed (10N91A0338)

Under the esteemed guidance of

Smt.sri Deepthi. I

Assistant Professor

Department of Mechanical Engineering

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD

VIVEKANANDA INSTITUTE OF TECHNOLOGY & SCIENCE (N9)

KARIMNAGAR (505001)

ANDHRAPRADESH

Opp: Housing Board Colony, Bye-Pass Road, Karimnagar-505001

(2010-2014)

2

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY

VIVEKANANDA INSTITUTE OF TECHNOLOGY AND SCIENCE

KARIMANAGAR (505001)

DEPARTMENT OF MECHANICAL ENGINEERING

College Code N9

CERTIFICATE

This is to certify that the project entitled “DETECTOBOT”, is bonafide work of Md

Hasan Ali(10N91A0331) & Syed Mobeenuddin (10N91A0357), Md Abdul Akheel

(10N91A0330), Syed Raufuddin (10N91A0335), Md Umair Ahmed (10N91A0338)

submitted to the faculty of mechanical engineering in partial fulfilment of the requirements for

the award of the Degree of Bachelor of Technology in Department of Mechanical

Engineering, from Jawaharlal Nehru Technological University Hyderabad.

The work embodied in this technical has not been submitted to any other institution for

the award of any degree.

Signature of guide

SMT.Sri Deepthi.I

Asst.professor

Vivekananda Institute of Technology & Science

Karimnagar-505001

signature head of the Department

SMT.Sri Deepthi.I,

Asst Professor,

Head of Department of ME,

Vivekananda Institute of Technology

3

ABSTRACT

Need

Many advances in technology have been providing many solutions in protection, either it be the

protection of our homes or it be in the land of border security, in which we are losing lives of

many security forces men and other high profile personnel.

One of the ways of reducing this loss of lives is to keep regular eye at places of having no risk of

lives at all. If something terrible happens at your job, you might file a report about it and your

boss will follow up on it. If something terrible happens at a bomb tech’s job, they might get

exploded. A tragedy if it’s a human being. But if it’s a robot? A small lump sum out of the

defence budget.

 Robots have been asked to perform jobs in some pretty intense places, from war zones in the

Middle East to the surface of Mars to the unexplored corners of Egypt's Great Pyramid.

Today, almost all the military organizations take the help of military robots to carry out many

risky jobs that cannot be handled manually by soldier. We have also seen a great development in

military robots when compare to military robots in earlier time. At present, different military

robots are utilized by many military organizations.

This robot utilizes two DC motors along with tank belts which are flexible enough to climb small

obstacles, controlled by a wireless remote control, and an onboard camera rotating 360 degrees

giving a complete picture of surrounding and providing an extra feature of visual intelligence.

A microcontroller controls the DC motors in order to move the vehicle on the ground. The

movement of the DC motors is in clock and anti-clockwise direction. The navigation system is

the important factor in the robot as it utilizes the movement of belts which can almost run on any

surface letting it be one of the finest navigating robots.

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Objective

Objective of this project is to save human lives by continuously monitoring the surroundings and

detect, being live feed has a great advantage of where actually the destity is going on.

The use of robots in warfare, although traditionally a topic for science fiction, is being

researched as a possible future means of fighting wars. Already several military robots have been

developed by various armies.

Military robots come in different shapes and sizes as per the task they are designated for. In the

development of military robots, we can consider US Mechatronics which has created or

developed a working automated sentry gun and is presently developing it further for commercial

as well as military use. As far as military robots development is concerned, we cannot forget

MIDARS which is a four-wheeled military robot. This robot is outfitted with many cameras,

radar, and a firearm that performs arbitrary patrols around a military base automatically.

Military robotics isn’t about creating an army of humanoids but utilization of robotics

technology for fighting terror and defending the nation. Thus, military robots need not be

humanoids or they not necessarily need to carry weapons, they are just those robots that can help

the armed forces. The opportunities offered by these technologies are boundless.

Pretty much by definition, the military is a dangerous place for humans. This makes it a logical

application for robotics. Robotics has been a staple of advanced manufacturing for over half a

century. As robots and their peripheral equipment become more sophisticated, reliable and

miniaturized, these systems are increasingly being utilized for military and law enforcement

purposes. Mobile robotics play an increasingly important role in military matters, from patrol to

dealing with potential explosives.

Implementation

The mobile robotic platform is mounted on a rectangular box with electronic equipment. The

platform moves on wheels or tracks, or both, and is usually battery-powered. Communication

equipment and sensors can detect images.

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Mobile robotic platforms used in national security applications must move within unstructured

environments. “The ability to operate over challenging terrain and the ability to autonomously

navigate in unstructured environments are areas of focus for this project.

Result

Implementation in sand and harsh environments has been done and positive results have been

obtained clearing almost any obstacle within its range of height this robot has been tested.

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CONTENTS

Chapter 1: Introduction

1.1 Area of Research

1.2 Motivation

1.3 Objective

Chapter 2: Introduction to Embedded Systems

2.1 What is an embedded system?

2.2 Features of embedded systems

2.3. Applications of Embedded Systems

2.3.1 Consumer applications

2.3.2 Office automation

2.3.3 Industrial automation

2.3.4 Medical electronics

Chapter 3: Microcontroller

3.1 AT89S52

3.2 Features

3.3 Pin Configuration

3.4 History Of 8051

3.4.1 AT89S52

3.4.2 Introduction to AT89S52

3.4.3 Pin Diagram

Chapter 4: HT 12E ENCODER

4.1 Features

4.2 Applications

4.3 General Description

Chapter 5: 433 MHZ RF TRANSMITTER STT-433

5.1 Overview

5.2 Features

CHAPTER 6:433 MHZ RF RECEIVER STR-433

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6.1 Overview

6.2 Features

6.3 Applications

Chapter 7: Relays

7.1 Overview of Relays

Chapter 8: ULN 2003

8.1 Darlington Pair

Chapter 9: Gear Motor

9.1 Operation Principle

9.1.1 Gear

9.2 Speed Reduction

9.3 Torque Multiplication

9.4 Application

Chapter 10: Regulated Power Supply

10.1 Transformer

10.2 rectifiers

10.2.1 Types of Rectifiers

10.2.1.1 Comparison of Rectifiers

10.3 Operation

10.4 Filter

10.5 Capacitor

10.6 Regulator

10.7 Features

Chapter 11: Hardware Configuration11.1 wireless camera

11.2 The chassis

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11.3 Anti corrosion paint

Chapter 12: Other Aspects12.1 Advantages

12.2 Application

12.3 Future Scope and Aspects

Conclusions

References

List of Figures

Chapter 2

Fig 2.1 Microwave Oven

Fig 2.2 Kitchen Equipment

Fig 2.3 Coffee Maker

Fig 2.4 Fax Machine

Fig 2.5 Printing Machine

Fig 2.6 Robot

Fig 2.7 Industrial Application

Fig 2.8 Hearts Beat Monitoring

Fig 2.9 Pulse Monitoring

Fig 2.10 Temperature Monitoring

Fig 2.11 Attendant Calling

Fig 2.12 Computer Software

Fig 2.13 Tele Communications

Fig 2.14 Web Camera

Chapter 3

Fig 3.1 Pin Configuration

Fig 3.2 At89s52

Fig 3.3 Block Diagram

Fig 3.4 Pin Diagram

Fig 3.5 Functional Block Diagram

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Fig 3.6 Oscillator And Timing Circuit

Chapter 4

Fig 4.1 Ht12e Encoder

Fig 4.2 Pin Description

Fig 4.3 Block Diagram

Chapter 5

Fig 5.1 433 M Hz RF Transmitters STT 433

Chapter 6

Fig 6.1 433 M Hz RF Receivers STR 433

Chapter 7

Fig 7.1 Relay

Fig 7.2 Switch Contacts

Fig 7.3 SPDT Relay

Fig 7.4 SPDT Relay Rest

Fig 7.5 SPDT Relay Not Energised

Fig 7.6 SPDT Relay Energised

Fig 7.7 SPDT Relay Complete Diagram

Chapter 8

Fig 8.1 ULN 2003

Fig 8.2 Pin Connection And Block Diagram

Fig 8.3 Darlington Pair

Chapter 9

Fig 9.1 Gear Connection

Fig 9.2 Dc Gear Motor

Fig 9.3 Motor Adjustment

Fig 9.4 Gear Alignment

Fig 9.5 Gear Movement

Chapter 10

Fig 10.1 Components of Power Supply

Fig 10.2 Transformer

Fig 10.3 Rectifier

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Fig 10.4 Operation

Fig 10.5 Alternating Current In Relay

Fig 10.6 3 Terminal Voltage Regulator

Chapter 11

Fig 11.1 Wireless Camera

Fig 11.2 Chassis

LIST OF TABLES

Chapter 3

Table No 3.1 Port Pin And Alternating Function

Table No 3.2 Port Pin And Alternating Function 2

Chapter 4

Table No 4.1 Pin Descriptions

Table No 4.2 Transmission Pin Descriptions

Chapter 5

Table No 5.1 Specification

Table No 5.2 Pin Descriptions

Chapter 6

Table No 6.1 Specification of Receiver

Table No 6.2 Pin Outs and Description

Chapter 10

Table No 10.1 Rectifier Parameters and Types

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CHAPTER 1

INTRODUCTION

1.1 Area of Research

Mechatronics is a design process that includes a combination of mechanical engineering,

electrical engineering, telecommunications engineering, control engineering and computer

engineering. Mechatronics is a multidisciplinary field of engineering, that is to say, it rejects

splitting engineering into separate disciplines. Originally, Mechatronics just included the

combination of mechanics and electronics, hence the word is a combination of mechanics and

electronics; however, as technical systems have become more and more complex the word has

been broadened to include more technical areas.

Mechanical modelling calls for modelling and simulating physical complex phenomenon in the

scope of a multi-scale and multi-physical approach. This implies to implement and to manage

modelling and optimization methods and tools, which are integrated in a systemic approach. The

specialty is aimed at students in mechanics who want to open their mind to systems engineering,

and able to integrate different physics or technologies, as well as students in Mechatronics who

want to increase their knowledge in optimization and multidisciplinary simulation techniques.

The specialty educates students in robust and/or optimized conception methods for structures or

many technological systems, and to the main modelling and simulation tools used in R&D.

Special courses are also proposed for original applications (multi-materials composites,

innovating transducers and actuators, integrated systems, …) to prepare the students to the

coming breakthrough in the domains covering the materials and the systems. For some

Mechatronics systems, the main issue is no longer how to implement a control system, but how

to implement actuators. Within the Mechatronics field, mainly two technologies are used to

produce movement/motion.

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1.2 Motivation

Motivation towards this project was when the killing of one of the military personnel due to

unusual circumstances while patrolling, and hence this project has been made so that to send this

robot for patrolling rather than sending a human which would rather save his life.

Until recently, robots have not been capable of understanding and coping with unstructured

environments (like the ones humans work in) because their systems have relied on knowing in

advance the specifics of every possible situation they might encounter. Each response to a

contingency has had to be programmed in advance, and systems have had to rebuild their world

model from sensor data each time they had to perform a new task.

This research is part of a large project which its main objective is to build an autonomous and

social robot. The robot must learn to select the right behaviours in order to achieve its goals. The

mechanisms involved in the decision making process are inspired on those used by humans and

animals. Since it is a social robot, one of the required features would be the life-like appearance.

The social aspect of the robot will be reflected in the fact that the human interaction is not going

to be considered as a complement of the rest of functionalities of the robot, but as one of its basic

features. For this kind of robots autonomy and emotions make them behave as if they were

''alive''. This feature would help people to think of them not as simple machines, but as real

companions. For certain applications, a robot with its own personality is more attractive than

another that simply executes the actions that it is programmed to do

1.3 Objective

Robotics is done with many different objectives, often at the same time. These include creating

useful controllers for real-world robot tasks, exploring the intricacies of evolutionary theory.

This is very time consuming, which is one of the reasons why controller evolution is usually

done in software. Also, initial random controllers may exhibit potentially harmful behaviour,

such as repeatedly crashing into a wall, which may damage the robot, and certainly the objective

is defined to be the main intention in this case of robot automation.

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CHAPTER 2

INTRODUCTION TO EMBEDDED SYSTEMS

2.1 What is an embedded system?

An embedded system is a computing device, which is a combination of both hardware and

software used to perform a specific task at specific intervals of time

Eg: Microwave oven, washing machines, vcd players etc

2.2 Features of embedded systems:

1. This system can do a specific task and cannot be programmed to do different operated

things

2. The software that is used in the embedded system is fixed

(i.e., like in computers multi software’s are used at a time)

3. The power consumption for the embedded system is very low

4 Embedded systems have very limited resources.

Nearly 99% of the processors are manufactured using embedded systems

2.3. Applications Of Embedded Systems

2.3.1. Consumer applications:

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At home we use a number of embedded systems which include microwave oven, remote control,

vcd players, dvd players, camera etc….

Microwave oven:

FIG 2.1

Automatic kitchen equipments:

FIG 2.2

Automatic coffee makes equipment:

15

FIG 2.3

2.3.2 Office automation:

We use systems like fax machine, modem, printer etc…

Fax machine:

FIG 2.4

Printing machine

FIG 2.5

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2.3.3 Industrial automation:

Today a lot of industries are using embedded systems for process control. In industries we design

the embedded systems to perform a specific operation like monitoring temperature, pressure,

humidity ,voltage, current etc.., and basing on these monitored levels we do control other

devices, we can send information to a centralized monitoring station.

Robot:

FIG 2.6

In critical industries where human presence is avoided there we can use Robots which are

programmed to do a specific operation.

Industrial equipments:

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FIG 2.7

2.3.4 Medical electronics:

Heart beat monitoring cum controlling equipment:

FIG 2.8

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Pulse monitoring system:

FIG 2.9

Almost every medical equipment in hospitals are embedded systems eg.. , like EEG, ECG,

scanners, endoscopes, X-Ray etc..,,

Temperature monitoring equipment:

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FIG 2.10

Nurse and attendant calling system using embedded systems.

FIG 2.11

Computer networking:

Embedded systems are used as bridges routers etc..

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FIG 2.12

Tele communications:

Cell phones, web cameras etc..

FIG 2.13

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Web camera:

FIG 2.14

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CHAPTER 3

MICROCONTROLLER

3.1 AT89S52:

The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with 8k bytes

of in-system programmable Flash memory. The device is manufactured using Atmel’s high-

density nonvolatile memory technology and is compatible with the industry-standard 80C51

instruction set and pinout. The on-chip Flash allows the program memory to be reprogrammed

in-system or by a conventional nonvolatile memory pro- grammer. By combining a versatile 8-bit

CPU with in-system programmable Flash on a monolithic chip, the Atmel AT89S52 is a

powerful microcontroller which provides a highly-flexible and cost-effective solution to many

embedded control applications. The AT89S52 provides the following standard features: 8K bytes

of Flash, 256 bytes of RAM, 32 I/O lines, Watchdog timer, two data pointers, three 16-bit

timer/counters, a six-vector two-level interrupt architecture, a full duplex serial port, on-chip

oscillator, and clock circuitry. In addition, the AT89S52 is designed with static logic for

operation down to zero frequency and supports two software selectable power saving modes. The

Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port, and interrupt

system to continue functioning. The Power-down mode saves the RAM con- tents but freezes the

oscillator, disabling all other chip functions until the next interrupt or hardware reset.

3.2 FEATURES:

• COMPATIBLE WITH MCS-51®

PRODUCTS

• 8K BYTES OF IN-SYSTEM PROGRAMMABLE (ISP) FLASH MEMORY

– ENDURANCE: 1000 WRITE/ERASE CYCLES

• 4.0V TO 5.5V OPERATING RANGE

• FULLY STATIC OPERATION: 0 HZ TO 33 MHZ

• THREE-LEVEL PROGRAM MEMORY LOCK

• 256 X 8-BIT INTERNAL RAM

• 32 PROGRAMMABLE I/O LINES

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• THREE 16-BIT TIMER/COUNTERS

• EIGHT INTERRUPT SOURCES

• FULL DUPLEX UART SERIAL CHANNEL

• LOW-POWER IDLE AND POWER-DOWN MODES

• INTERRUPT RECOVERY FROM POWER-DOWN MODE

• WATCHDOG TIMER

• DUAL DATA POINTER

• POWER-OFF FLAG

3.3 Pin Configuration:

FIG NO 3.1

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3.4 A BRIEF HISTORY OF 8051

In 1981, Intel Corporation introduced an 8 bit microcontroller called 8051. This

microcontroller had 128 bytes of RAM, 4K bytes of chip ROM, two timers, one serial port, and

four ports all on a single chip. At the time it was also referred as “A SYSTEM ON A CHIP”

3.4.1 AT89S52:

The AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with 8K bytes of

in-system programmable Flash memory. The device is manufactured using Atmel’s high-density

nonvolatile memory technology and is compatible with the industry-standard 80C51 instruction

set and pin out. The on-chip Flash allows the program memory to be reprogrammed in-system or

by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with in-

system programmable Flash on a monolithic chip, the Atmel AT89S52 is a powerful micro-

controller, which provides a highly flexible and cost-effective solution to many, embedded

control applications. The AT89S52 provides the following standard features: 8K bytes of Flash,

256 bytes of RAM, 32 I/O lines, Watchdog timer, two data pointers, three 16-bit timer/counters,

a six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and

clock circuitry. In addition, the AT89S52 is designed with static logic for operation down to zero

frequency and supports two software selectable power saving modes. The Idle Mode stops the

CPU while allowing the RAM, timer/counters, serial port, and interrupt system to continue

functioning. The Power-down mode saves the RAM con-tents but freezes the oscillator,

disabling all other chip functions until the next interrupt

FIG 3.2 (AT89S52)

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FIG 3.3 MICRO CONTROLLER BLOCK DIAGRAM

8031 has 128 bytes of RAM, two timers and 6 interrupts.

8051 has 4K ROM, 128 bytes of RAM, two timers and 6 interrupts.

8052 has 8K ROM, 256 bytes of RAM, three timers and 8 interrupts.

Of the three microcontrollers, 8051 is the most preferable. Microcontroller supports both

serial and parallel communication.

In the concerned project 8052 microcontroller is used. Here microcontroller used is

AT89S52, which is manufactured by ATMEL laboratories.

The 8051 is the name of a big family of microcontrollers. The device which we are going

to use along this tutorial is the 'AT89S52' which is a typical 8051 microcontroller manufactured

by Atmel™. Note that this part doesn't aim to explain the functioning of the different

components of a 89S52 microcontroller, but rather to give you a general idea of the organization

of the chip and the available features, which shall be explained in detail along this tutorial.

The block diagram provided by Atmel™ in their datasheet showing the architecture the 89S52

26

device can seem very complicated, and since we are going to use the C high level language to

program it, a simpler architecture can be represented as the figure 1.2.A.

This figure shows the main features and components that the designer can interact with. You can

notice that the 89S52 has 4 different ports, each one having 8 Input/output lines providing a total

of 32 I/O lines. Those ports can be used to output DATA and orders do other devices, or to read

the state of a sensor, or a switch. Most of the ports of the 89S52 have 'dual function' meaning that

they can be used for two different functions: the fist one is to perform input/output operations

and the second one is used to implement special features of the microcontroller like counting

external pulses, interrupting the execution of the program according to external events,

performing serial data transfer or connecting the chip to a computer to update the software.

3.4.2 Introduction to AT89S52

The system requirements and control specifications clearly rule out the use of 16, 32 or 64

bit micro controllers or microprocessors. Systems using these may be earlier to implement due to

large number of internal features. They are also faster and more reliable but, the above

application is satisfactorily served by 8-bit micro controller. Using an inexpensive 8-bit

Microcontroller will doom the 32-bit product failure in any competitive market place. Coming to

the question of why to use 89S52 of all the 8-bit Microcontroller available in the market the main

answer would be because it has 8kB Flash and 256 bytes of data RAM32 I/O lines, three 16-bit

timer/counters, a Eight-vector two-level interrupt architecture, a full duplex serial port, on-chip

oscillator, and clock circuitry.

In addition, the AT89S52 is designed with static logic for operation down to zero

frequency and supports two software selectable power saving modes. The Idle Mode stops the

CPU while allowing the RAM, timer/counters, serial port, and interrupt system to continue

functioning. The Power down Mode saves the RAM contents but freezes the oscillator, disabling

all other chip functions until the next hardware reset. The Flash program memory supports both

parallel programming and in Serial In-System Programming (ISP). The 89S52 is also In-

Application Programmable (IAP), allowing the Flash program memory to be reconfigured even

while the application is running.

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By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89S52 is

a powerful microcomputer which provides a highly flexible and cost effective solution to many

embedded control applications.

Features

Compatible with MCS-51 Products

8K Bytes of In-System Reprogrammable Flash Memory

Fully Static Operation: 0 Hz to 33 MHz

Three-level Program Memory Lock

256 x 8-bit Internal RAM

32 Programmable I/O Lines

Three 16-bit Timer/Counters

Eight Interrupt Sources

Programmable Serial Channel

Low-power Idle and Power-down Modes

4.0V to 5.5V Operating Range

Full Duplex UART Serial Channel

Interrupt Recovery from Power-down Mode

Watchdog Timer

Dual Data Pointer

Power-off Flag

Fast Programming Time

Flexible ISP Programming (Byte and Page Mode)

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3.4.3 PIN DIAGRAM

FIG-3.4 PIN DIAGRAM OF 89S52 IC

3.4.4PIN DESCRIPTION

Pin Description

VCC: Supply voltage.

GND: Ground

Port 0

Port 0 is an 8-bit open drain bidirectional I/O port. As an output port, each pin can sink eight

TTL inputs. When 1s are written to port 0 pins, the pins can be used as high impedance inputs.

Port 0 can also be configured to be the multiplexed low order address/data bus during accesses to

external program and data memory. In this mode, P0 has internal pull-ups. Port 0 also receives

the code bytes during Flash programming and outputs the code bytes during program

verification.External pull-ups are required during program verification.

Port 1

29

Port 1 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 1 output buffers can

sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high by the

internal pull-ups and can be used as inputs. As inputs, Port 1 pins that are externally being pulled

low will source current (IIL) because of the internal pull-ups. In addition, P1.0 and P1.1 can be

configured to be the timer/counter 2 external count input (P1.0/T2) and the timer/counter 2

trigger input (P1.1/T2EX), respectively, as shown in the following table. Port 1 also receives the

low-order address bytes during Flash programming and verification.

TABLE 3.1

Port 2

Port 2 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 2 output buffers can

sink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled high by

the internal pull-ups and can be used as inputs. As inputs, Port 2 pins that are externally being

pulled low will source current (IIL) because of the internal pull-ups. Port 2 emits the high-order

address byte during fetches from external program memory and during accesses to external data

memory that uses 16-bit addresses (MOVX @ DPTR). In this application, Port 2 uses strong

internal pull-ups when emitting 1s. During accesses to external data memory that uses 8-bit

addresses (MOVX @ RI), Port 2 emits the contents of the P2 Special Function Register. Port 2

also receives the high-order address bits and some control signals during Flash programming and

verification.

Port 3

Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. The Port 3 output buffers can

sink/source four TTL inputs. When 1s are written to Port 3 pins, they are pulled high by the

internal pull-ups and can be used as inputs. As inputs, Port 3 pins that are externally being pulled

low will source current (IIL) because of the pull-ups. Port 3 also serves the functions of various

30

special features of the AT89S52, as shown in the following table. Port 3 also receives some

control signals for Flash programming and verification.

TABLE 3.2

RST

Reset input. A high on this pin for two machine cycles while the oscillator is running

resets the device. This pin drives High for 96 oscillator periods after the Watchdog times out.

The DISRTO bit in SFR AUXR (address 8EH) can be used to disable this feature. In the default

state of bit DISRTO, the RESET HIGH out feature is enabled. ALE/PROG Address Latch Enable

(ALE) is an output pulse for latching the low byte of the address during accesses to external

memory. This pin is also the program pulse input (PROG) during Flash programming. In normal

operation, ALE is emitted at a constant rate of 1/6 the oscillator frequency and may be used for

external timing or clocking purposes. Note, however, that one ALE pulse is skipped during each

access to external data memory. If desired, ALE operation can be disabled by setting bit 0 of

SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC instruction.

Otherwise, the pin is weakly pulled high. Setting the ALE-disable bit has no effect if the

microcontroller is in external execution mode.

PSEN

Program Store Enable (PSEN) is the read strobe to external program memory. When the

AT89S52 is executing code from external program memory, PSEN is activated twice each

machine cycle, except that two PSEN activations are skipped during each access to external data

memory.

EA/VPP

External Access Enable. EA must be strapped to GND in order to enable the device to

fetch code from external program memory locations starting at 0000H up to FFFFH. Note,

31

however, that if lock bit 1 is programmed, EA will be internally latched on reset. EA should be

strapped to VCC for internal program executions. This pin also receives the 12-volt

programming enable voltage (VPP) during Flash programming.

XTAL1

Input to the inverting oscillator amplifier and input to the internal clock operating circuit.

XTAL2: Output from the inverting oscillator amplifier.

FIG-3.5 Functional block diagram of micro controller

The 8052 Oscillator and Clock:

The heart of the 8051 circuitry that generates the clock pulses by which all the

internal all internal operations are synchronized. Pins XTAL1 And XTAL2 is provided for

connecting a resonant network to form an oscillator. Typically a quartz crystal and capacitors are

employed. The crystal frequency is the basic internal clock frequency of the microcontroller. The

manufacturers make 8051 designs that run at specific minimum and maximum frequencies

typically 1 to 16 MHz

32

Fig-3.6 Oscillator and timing circuit

33

CHAPTER 4

HT 12E ENCODER

4.1 Features

Operating voltage

2.4V~5V for the HT12A

2.4V~12V for the HT12E

Low power and high noise immunity CMOS technology

Low standby current: 0.1_A (typ.) at VDD=5V

HT12A with a 38kHz carrier for infrared transmission medium

Minimum transmission word

Four words for the HT12E

Built-in oscillator needs only 5% resistor

Data code has positive polarity

Minimal external components

HT12E: 18-pin DIP

FIG 4.1

4.2 Applications

Burglar alarm system

Smoke and fire alarm system

Garage door controllers

Car door controllers

Car alarm system

Security system

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Cordless telephones

Other remote control systems

4.3 General Description

The 212 encoders are a series of CMOS LSIs for remote control system applications. They are

capable of encoding information which consists of N address bits and 12_N data bits. Each

address/ data input can be set to one of the two logic states. The programmed addresses/data are

transmitted together with the header bits via an RF or an infrared transmission medium upon

receipt of a trigger signal. The capability to select a TE trigger on the HT12E or a DATA trigger

on the HT12A further enhances the application flexibility of the 212 series of encoders.

The HT12A additionally provides a 38kHz carrier for infrared systems.

FIG 4.2

35

TABLE NO 4.1

TABLE NO 4.2

36

FIG 4.3

Absolute Maximum Ratings

Supply Voltage (HT12A) .............._0.3V to 5.5V

Supply Voltage (HT12E) ..............._0.3V to 13V

Input Voltage....................VSS_0.3 to VDD+0.3V

Storage Temperature................._50_C to 125_C

Operating Temperature..............._20_C to 75_C

Note: These are stress ratings only. Stresses exceeding the range specified under

Absolute Maximum Ratings may cause substantial damage to the device. Functional

operation of this device at other conditions beyond those listed in the specification is not

implied and prolonged exposure to extreme conditions may affect device reliability.

Features

Operating voltage: 2.4V~12V

37

Low power and high noise immunity CMOS Technology

Low standby current Capable of decoding 12 bits of information Binary address setting

Received codes are checked 3 times Address/Data number combination

HT12D: 8 address bits and 4 data bits

HT12F: 12 address bits only

Built-in oscillator needs only 5% resistor valid transmission indicator

Easy interface with an RF or an infrared transmission medium

Minimal external components

Pair with Holtek_s 212 series of encoders

18-pin DIP, 20-pin SOP package

Applications

Burglar alarm system

Smoke and fire alarm system

Garage door controllers

Car door controllers

Car alarm system

Security system

Cordless telephones

38

CHAPTER 5

433 MHZ RF TRANSMITTER STT-433

5.1 Overview

The STT-433 is ideal for remote control applications where low cost and longer range is

required. The transmitter operates from a1.5-12V supply, making it ideal for battery-powered

applications. The transmitter employs a SAW-stabilized oscillator, ensuring accurate frequency

control for best range performance. Output power and harmonic emissions are easy to control,

making FCC and ETSI compliance easy. The manufacturing-friendly SIP style package and low-

cost make the STT-433 suitable for high volume applications.

FIG 5.1

5.2 Features

· 433.92 MHz Frequency

· Low Cost

· 1.5-12V operation

· 11mA current consumption at 3V

39

· Small size

· 4 dBm output power at 3V

3. Applications

Remote Keyless Entry (RKE)

Remote Lighting Controls

On-Site Paging

Asset Tracking

Wireless Alarm and Security Systems

Long Range RFID

Automated Resource Management

Table No 5.1

Table No 5.2

40

5.3 OPERATION

Theory

OOK(On Off Keying) modulation is a binary form of amplitude modulation. When a logical 0

(data line low) is being sent, the transmitter is off, fully suppressing the carrier. In this state, the

transmitter current is very low, less than 1mA. When a logical 1 is being sent, the carrier is fully

on. In this state, the module current consumption is at its highest, about 11mA with a 3V power

supply.

OOK is the modulation method of choice for remote control applications where power

consumption and cost are the primary factors. Because OOK transmitters draw no power when

they transmit a 0, they exhibit significantly better power consumption than FSK transmitters.

OOK data rate is limited by the start-up time of the oscillator. High-Q oscillators which have

very stable center frequencies take longer to start-up than low-Q oscillators. The start-up time of

the oscillator determines the maximum data rate that the transmitter can send.

Data Rate

The oscillator start-up time is on the order of 40uSec, which limits the maximum data rate to 4.8

kbit/sec.

SAW stabilized oscillator

The transmitter is basically a negative resistance LC oscillator whose center frequency is tightly

controlled by a SAW resonator. SAW (Surface Acoustic Wave) resonators are fundamental

frequency devices that resonate at frequencies much higher than crystals.

Typical Application

Remark: Antenna length about: 17cm for 433MHz

41

CHAPTER 6

433 MHZ RF RECEIVER STR-433

6.1 Overview

The STR-433 is ideal for short-range remote control applications where cost is a primary

concern. The receiver module requires no external RF components except for the antenna. It

generates virtually no emissions, making FCC and ETSI approvals easy. The super-regenerative

design exhibits exceptional sensitivity at a very low cost. The manufacturing-friendly SIP style

package and low-cost make the STR-433 suitable for high volume applications.

FIG 6.1

6.2 Features

· Low Cost

· 5V operation

· 3.5mA current drain

· No External Parts are required

· Receiver Frequency: 433.92 MHZ

· Typical sensitivity: -105dBm

· IF Frequency: 1MHz

6.3 Applications

· Car security system

· Sensor reporting

42

· Automation system

· Remote Keyless Entry (RKE)

· Remote Lighting Controls

· On-Site Paging

· Asset Tracking

· Wireless Alarm and Security Systems

· Long Range RFID

· Automated Resource Management

TABLE 6.1

FIG NO & TABLE NO 6.2

43

CHAPTER 7

RELAYS SPDT

FIG 7.1

7.1 Overview OF Relays

A relay is an electrically operated switch used to isolate one electrical circuit from another. In its

simplest form, a relay consists of a coil used as an electromagnet to open and close switch

contacts. Since the two circuits are isolated from one another, a lower voltage circuit can be used

to trip a relay, which will control a separate circuit that requires a higher voltage or amperage.

Relays can be found in early telephone exchange equipment, in industrial control circuits, in car

audio systems, in automobiles, on water pumps, in high-power audio amplifiers and as protection

devices.

Relay Switch Contacts

The switch contacts on a relay can be "normally open" (NO) or "normally closed" (NC)--that is,

when the coil is at rest and not energized (no current flowing through it), the switch contacts are

given the designation of being NO or NC. In an open circuit, no current flows, such as a wall

light switch in your home in a position that the light is off. In a closed circuit, metal switch

contacts touch each other to complete a circuit, and current flows, similar to turning a light

switch to the "on" position. In the accompanying schematic diagram, points A and B connect to

the coil. Points C and D connect to the

FIG NO 7.2

44

switch. When you apply a voltage across the coil at points A and B, you create an

electromagnetic field, which attracts a lever in the switch, causing it to make or break contact in

the circuit at points C and D (depending if the design is NO or NC). The switch contacts remain

in this state until you remove the voltage to the coil. Relays come in different switch

configurations. The switches may have more than one "pole," or switch contact. The diagram

shows a "single pole single throw" configuration, referred to as SPST. This is similar to a wall

light switch in your home. With a single "throw" of the switch, you close the circuit.

The Single Pole Double Throw Relay

A single pole double throw (SPDT) relay configuration switches one common pole to two other

poles, flipping between them. As shown in the schematic diagram, the common point E

completes a circuit with C when the relay coil is at rest, that is, no voltage is applied to it.

FIG NO 7.3

This circuit is "closed." A gap between the contacts of point E and D creates an "open" circuit.

When you apply power to the coil, a metal level is pulled down, closing the circuit between

points E and D and opening the circuit between E and C. A single pole double throw relay can be

used to alternate which circuit a voltage or signal will be sent to.

SPDT Relay:

(Single Pole Double Throw Relay) an electromagnetic switch, consist of a coil (terminals 85 &

86), 1 common terminal (30), 1 normally closed terminal (87a), and one normally open terminal

(87) (Figure 1).

When the coil of an SPDT relay (Figure 1) is at rest (not energized), the common terminal (30)

and the normally closed terminal (87a) have continuity. When the coil is energized, the common

terminal (30) and the normally open terminal (87) have continuity.

The diagram below center (Figure 2) shows an SPDT relay at rest, with the coil not energized.

45

The diagram below right (Figure 3) shows the relay with the coil energized. As you can see, the

coil is an electromagnet that causes the arm that is always connected to the common (30) to pivot

when energized whereby contact is broken from the normally closed terminal (87a) and made

with the normally open terminal (87).

When energizing the coil of a relay, polarity of the coil does not matter unless there is a diode

across the coil. If a diode is not present, you may attach positive voltage to either terminal of the

coil and negative voltage to the other, otherwise you must connect positive to the side of the coil

that the cathode side (side with stripe) of the diode is connected and negative to side of the coil

that the anode side of the diode is connected.

FIG 7.4

FIG 7.5

FIG 7.6

Why do I want to use a relay and do I really need to?

Anytime you want to switch a device which draws more current than is provided by an output of

a switch or component you'll need to use a relay. The coil of an SPDT or an SPST relay that we

most commonly use draws very little current (less than 200 milliamps) and the amount of current

46

that you can pass through a relay's common, normally closed, and normally open contacts will

handle up to 30 or 40 amps. This allows you to switch devices such as headlights, parking lights,

horns, etc., with low amperage outputs such as those found on keyless entry and alarm systems,

and other components. In some cases you may need to switch multiple things at the same time

using one output. A single output connected to multiple relays will allow you to open continuity

and/or close continuity simultaneously on multiple wires.

There are far too many applications to list that require the use of a relay, but we do show many

of the most popular applications in the pages that follow and many more in our Relay Diagrams -

Quick Reference application. If you are still unclear about what a relay does or if you should use

one after you browse through the rest of this section, please post a question in the12volt's install

bay. (We recommend Tyco (formerly Bosch) or Potter & Brumfield relays for all of the SPDT

and SPST relay applications shown on this site.)

FIG 7.7

47

CHAPTER 8

ULN2003

ULN is mainly suited for interfacing between low-level circuits and multiple peripheral power

loads,.The series ULN20XX high voltage, high current darlington arrays feature continuous load

current ratings. The driving circuitry in- turn decodes the coding and conveys the necessary data

to the stepper motor, this module aids in the movement of the arm through steppers

FIG 8.1

FIG 8.2

48

The driver makes use of the ULN2003 driver IC, which contains an array of 7 power Darlington

arrays, each capable of driving 500mA of current. At an approximate duty cycle, depending

on ambient temperature and number of drivers turned on, simultaneously typical power

loads totaling over 230w can be controlled.The device has base resistors, allowing direct

connection to any common logic family. All the emitters are tied together and brought out

to a separate terminal. Output protection diodes are included; hence the device can drive

inductive loads with minimum extra components. Typical loads include relays, solenoids,

stepper motors, magnetic print hammers, multiplexed LED, incandescent displays and

heaters.

8.1 Darlington Pair

hat is a Darlington Pair?

A Darlington pair is two transistors that act as a single transistor but with a much

higher current gain.

What is current gain?

Transistors have a characteristic called current gain. This is referred to as its hFE.

The amount of current that can pass through the load when connected to a

transistor that is turned on equals the input current x the gain of the transistor

(hFE) The current gain varies for different transistor and can be looked up in the

data sheet for the device. Typically it may be 100. This would mean that the

current available to drive the load would be 100 times larger than the input to the

transistor.

FIG 8.3

49

CHAPTER 9

GEAR MOTOR

What Is a Gear Motor?

Gear motors are complete motive force systems consisting of an electric motor

and a reduction gear train integrated into one easy-to-mount and -configure package. This greatly

reduces the complexity and cost of designing and constructing power tools, machines and

appliances calling for high torque at relatively low shaft speed or RPM. Gear motors allow the

use of economical low-horsepower motors to provide great motive force at low speed such as in

lifts, winches, medical tables, jacks and robotics. They can be large enough to lift a building or

small enough to drive a tiny clock.

.

FIG 9.1

12V High Torque

DC GEAR MOTOR FIG 9.2

50

9.1 Operation Principle

Most synchronous AC electric motors have output ranges of from 1,200 to 3,600 revolutions per

minute. They also have both normal speed and stall-speed torque specifications. The reduction

gear trains used in gear

motors are designed to reduce the output speed while increasing the torque. The increase in

torque is inversely proportional to the reduction in speed. Reduction gearing allows small electric

motors to move large driven loads, although more slowly than larger electric motors. Reduction

gears consist of a small gear driving a larger gear. There may be several sets of these reduction

gear sets in a reduction gear box.

9.1.1 Gear

Toothed wheel that transmits the turning movement of one shaft to another shaft. Gear wheels

may be used in pairs or in threes if both shafts are to turn in the same direction. The gear ratio –

the ratio of the number of teeth on the two wheels – determines the torque ratio, the turning force

on the output shaft compared with the turning force on the input shaft. The ratio of the angular

velocities of the shafts is the inverse of the gear ratio.

The common type of gear for parallel shafts is the spur gear, with straight teeth parallel to the

shaft axis. The helical gear has teeth cut along sections of a helix or corkscrew shape; the double

form of the helix gear is the most efficient for energy transfer. Bevel gears, with tapering teeth

set on the base of a cone, are used to connect intersecting shafts.

FIG 9.3

51

FIG 9.4

The toothed and interlocking wheels which make up a typical gear movement.

Gear ratio is calculated by dividing the number of teeth on the driver gear by the number of teeth

on the driven gear (gear ratio = driver/driven); the idler gears are ignored. Idler gears change the

direction of rotation but do not affect speed. A high driven to driver ratio (middle) is a speed-

reducing ratio.

FIG 9.5

Different gears are used to perform different engineering functions depending on the change in

direction of motion that is needed. Rack and pinion gears are the commonest gears and are used

in car steering mechanics.

9.2 Speed Reduction

Sometimes the goal of using a gear motor is to reduce the rotating shaft speed of a motor

in the device being driven, such as in a small electric clock where the tiny synchronous

motor may be spinning at 1,200 rpm but is reduced to one rpm to drive the second hand,

and further reduced in the clock mechanism to drive the minute and hour hands. Here the

amount of driving force is irrelevant as long as it is sufficient to overcome the frictional

effects of the clock mechanism.

9.3 Torque Multiplication

Another goal achievable with a gear motor is to use a small motor to generate a very

large force albeit at a low speed. These applications include the lifting mechanisms on

hospital beds, power recliners, and heavy machine lifts where the great force at low speed

is the goal.

52

Motor Varieties

Most industrial gear motors are AC-powered, fixed-speed devices, although there are

fixed-gear-ratio, variable-speed motors that provide a greater degree of control. DC gear

motors are used primarily in automotive applications such as power winches on trucks,

windshield wiper motors and power seat or power window motors.

9.4 Applications

What power can openers, garage door openers, stair lifts, rotisserie motors, timer cycle

knobs on washing machines, power drills, cake mixers and electromechanical clocks

have in common is that they all use various integrations of gear motors to derive a large

force from a relatively small electric motor at a manageable speed. In industry, gear

motor applications in jacks, cranes, lifts, clamping, robotics, conveyance and mixing are

too numerous to count.

53

CHAPTER 10

REGULATED POWER SUPPLY

The power supplies are designed to convert high voltage AC mains electricity to a

suitable low voltage supply for electronics circuits and other devices. A RPS (Regulated Power

Supply) is the Power Supply with Rectification, Filtering and Regulation being done on the AC

mains to get a Regulated power supply for Microcontroller and for the other devices being

interfaced to it.

A power supply can by broken down into a series of blocks, each of which performs a particular

function. A d.c power supply which maintains the output voltage constant irrespective of a.c

mains fluctuations or load variations is known as “Regulated D.C Power Supply”

For example a 5V regulated power supply system as shown below:

FIG 10.1

54

10.1 Transformer:

A transformer is an electrical device which is used to convert electrical power

from one Electrical circuit to another without change in frequency.

Transformers convert AC electricity from one voltage to another with little loss of power.

Transformers work only with AC and this is one of the reasons why mains electricity is AC. Step-

up transformers increase in output voltage, step-down transformers decrease in output voltage.

Most power supplies use a step-down transformer to reduce the dangerously high mains

voltage to a safer low voltage. The input coil is called the primary and the output coil is called

the secondary. There is no electrical connection between the two coils; instead they are linked

by an alternating magnetic field created in the soft-iron core of the transformer. The two lines in

the middle of the circuit symbol represent the core. Transformers waste very little power so

the power out is (almost) equal to the power in. Note that as voltage is stepped down current is

stepped up. The ratio of the number of turns on each coil, called the turn’s ratio, determines

the ratio of the voltages. A step-down transformer has a large number of turns on its primary

(input) coil which is connected to the high voltage mains supply, and a small number of turns on

its secondary (output) coil to give a low output voltage.

An Electrical Transformer

FIG 10.2

55

Turns ratio = Vp/ VS = Np/NS

Power Out= Power In

VS X IS=VP X IP

Vp = primary (input) voltage

Np = number of turns on primary coil

Ip  = primary (input) current    

10.2 RECTIFIER:

A circuit which is used to convert a.c to dc is known as RECTIFIER. The process of

conversion a.c to d.c is called “rectification”

Parameter

Type of Rectifier

Half wave Full wave Bridge

Number of diodes

1

2

4

PIV of diodes

Vm

2Vm

Vm

D.C output voltage

Vm/

2Vm/

2Vm/

Vdc,at

no-load

0.318Vm

0.636Vm 0.636Vm

Ripple factor

1.21

0.482

0.482

Ripple

frequency

f

2f

2f

Rectification

efficiency

0.406

0.812

0.812

56

Transformer

Utilization

Factor(TUF)

0.287 0.693 0.812

RMS voltage Vrms Vm/2 Vm/√2 Vm/√2

TABLE NO 10.1

10.2.1 TYPES OF RECTIFIERS:

Half wave Rectifier

Full wave rectifier

1. Centre tap full wave rectifier.

2. Bridge type full bridge rectifier.

10.2.1.1Comparison of rectifier circuits:

Full-wave Rectifier From the above comparison we came to know that full wave bridge rectifier

as more advantages than the other two rectifiers. So, in our project we are using full wave bridge

rectifier circuit.

Bridge Rectifier A bridge rectifier makes use of four diodes in a bridge arrangement to achieve

full-wave rectification. This is a widely used configuration, both with individual diodes wired as

shown and with single component bridges where the diode bridge is wired internally.

A bridge rectifier makes use of four diodes in a bridge arrangement as shown in fig (a)

to achieve full-wave rectification. This is a widely used configuration, both with individual

diodes wired as shown and with single component bridges where the diode bridge is wired

internally.

57

Fig 10.3

10.3 Operation:

During positive half cycle of secondary, the diodes D2 and D3 are in forward biased while D1

and D4 are in reverse biased as shown in the fig(b). The current flow direction is shown in the fig

(b) with dotted arrows.

Fig 10.4

During negative half cycle of secondary voltage, the diodes D1 and D4 are in forward biased

while D2 and D3 are in reverse biased as shown in the fig(c). The current flow direction is

shown in the fig (c) with dotted arrows.

58

Fig 10.5

10.4 Filter:

A Filter is a device which removes the a.c component of rectifier output but

allows the d.c component to reach the load

10.5 Capacitor Filter:

We have seen that the ripple content in the rectified output of half wave rectifier is 121% or

that of full-wave or bridge rectifier or bridge rectifier is 48% such high percentages of ripples is

not acceptable for most of the applications. Ripples can be removed by one of the following

methods of filtering.

A capacitor, in parallel to the load, provides an easier by –pass for the ripples voltage though it

due to low impedance. At ripple frequency and leave the D.C. to appear at the load.

An inductor, in series with the load, prevents the passage of the ripple current (due to high

impedance at ripple frequency) while allowing the d.c (due to low resistance to d.c)

Various combinations of capacitor and inductor, such as L-section filter section filter,

multiple section filter etc. which make use of both the properties mentioned in (a) and (b) above.

Two cases of capacitor filter, one applied on half wave rectifier and another with full wave

rectifier.

59

Filtering is performed by a large value electrolytic capacitor connected across the DC

supply to act as a reservoir, supplying current to the output when the varying DC voltage from

the rectifier is falling. The capacitor charges quickly near the peak of the varying DC, and then

discharges as it supplies current to the output. Filtering significantly increases the average DC

voltage to almost the peak value (1.4 × RMS value).

To calculate the value of capacitor(C),

C = ¼*√3*f*r*Rl

Where,

f = supply frequency,

r = ripple factor,

Rl = load resistance

Note: In our circuit we are using 1000µF hence large value of capacitor is placed to

reduce ripples and to improve the DC component.

10.6 Regulator:

Voltage regulator ICs is available with fixed (typically 5, 12 and 15V) or variable output

voltages. The maximum current they can pass also rates them. Negative voltage regulators are

available, mainly for use in dual supplies. Most regulators include some automatic protection

from excessive current ('overload protection') and overheating ('thermal protection'). Many of

the fixed voltage regulators ICs have 3 leads and look like power transistors, such as the 7805

+5V 1A regulator shown on the right. The LM7805 is simple to use. You simply connect the

positive lead of your unregulated DC power supply (anything from 9VDC to 24VDC) to the

Input pin, connect the negative lead to the Common pin and then when you turn on the power,

you get a 5 volt supply from the output pin.

60

Fig 10.6 Three Terminal Voltage Regulator

78XX:

The Bay Linear LM78XX is integrated linear positive regulator with three terminals. The

LM78XX offer several fixed output voltages making them useful in wide range of applications.

When used as a zener diode/resistor combination replacement, the LM78XX usually results in an

effective output impedance improvement of two orders of magnitude, lower quiescent current.

The LM78XX is available in the TO-252, TO-220 & TO-263packages,

10.7 Features:

• Output Current of 1.5A

• Output Voltage Tolerance of 5%

• Internal thermal overload protection

• Internal Short-Circuit Limited

• Output Voltage 5.0V, 6V, 8V, 9V, 10V, 12V, 15V, 18V, 24V.

61

CHAPTER 11

HARDWARE CONFIGURATION

11.1 Wireless Camera:

Smallest wireless video and audio camera in the world super mini type for surveillance attached

with a dc stepper motor; it acts as a 360’ acting type for search and support.

With an audio and video radio frequency module it gives a large variety of support towards a

high megapixel clarity interchange.

A receiver is to be attached to a laptop or a pc and transmitter is attached already with the camera

hence receiving and transmitting live feed from the surroundings.

Fig 11.1

11.2 The Chassis:

The chassis has been designed in such a way that the robot can easily climb an obstacle with

several calculations for balancing considering the centre of gravity.

Center of gravity is the point in a body around which the resultant torque due to gravity forces

vanishes. Near the surface of the earth, where the gravity acts downward as a parallel force field,

the center of gravity and the center of mass are the same.

62

An experimental method to locate the three-dimensional coordinates of the center of mass begins

by supporting the object at three points and measuring the forces, F1, F2, and F3 that resist the

weight of the object.

An experimental method for locating the center of mass is to suspend the object from two

locations and to drop plumb lines from the suspension points. The intersection of the two lines is

the center of mass

The shape of an object might already be mathematically determined, but it may be too complex

to use a known formula. In this case, one can subdivide the complex shape into simpler, more

elementary shapes, whose centers of mass are easy to find. If the total mass and center of mass

can be determined for each area, then the center of mass of the whole is the weighted average of

the centers. This method can even work for objects with holes, which can be accounted for as

negative masses.

Lathe machine operations such as drilling, boring, grinding, welding, shaping have been done in

order to make the chassis

Fig 11.2

63

11.3 Anti Corrosion Paint:

Anti corrosion paint has been applied so as to reduce the corrosion factor as the chassis is made

of iron and may corrode under circumstances.

Anti-corrosion refers to the protection of metal surfaces from corroding in high-risk (corrosive)

environments.

When metallic materials are put into corrosive environments, they tend to have chemical

reactions with the air and/or water. The effects of corrosion become evident on the surfaces of

these materials. For example, after putting the iron into a corrosive atmosphere for an extended

period, the iron starts rusting due to oxygen interaction with water on the iron's surface.

Therefore, metal equipment lacking any preventive (anti-corrosive) measures, may become

rusted both inside and out, depending upon atmospheric conditions and how much of that

equipment is exposed to the air. There are a number of methods for preventing corrosion,

especially in marine applications. Anti-corrosion measures are of particular importance in

environments where high humidity, mist, and salt are factors.

64

CHAPTER 12

12.1 Advantages:

Reduce risk of human Lives By exchanging places.

Constant Surveillance under Threat.

Reduces man power

Can be used in highly polluted environment where man cannot go.

12.2 Applications:

Border security

Regular surveillance

Internal security

12.3 Future Scope & Aspects:

For further development of this project we can add ultrasonic sensors and stair climbing

mechanisms for evaluation of distances and increased standard of low profile surveillance.

65

CONCLUSION

We conclude that with the use of this project we intend to reduce the risk of lives as well as

increase the border security and internal security in cities by constantly evaluating the

surrounding areas without disturbing the harmony of people, and high surveillance can be

monitored.

It has been developed by integrating features of all hardware and software components used.

.

66

REFERENCES

www.instructables.com

www. robots hop.com

www.societyofrobots.com/step_by_step_robot.shtml

electronics.howstuffworks.com/microcontroller.htm

LEGO MIND STORMS (LAURENS VOLK)

67