wireless warfare vehicle

WIRELESS WARFARE ROBOT

CHAPTER – 1

INTRODUCTION

Manpower scarcity has been a perennial problem for many armed forces around the

world. Over the years, there has been a decline in the absolute numerical make-up of these

organizations, which, if not managed properly, can affect their operational capabilities. This

scarcity is a situation that is unlikely to improve in the foreseeable future, given the current low

birth rates and conflicting demands for manpower.

From a numerical perspective, this constraint means that the armed forces cannot mass

together the sheer number of ground troops as before. From a risk perspective, every soldier on

the battlefield is now a precious resource which should not be exposed to unnecessary risks. This

translates into further constraints for battle planners, who may not have the leeway to select the

riskier but more expedient military options. Finally, from the skills perspective, smaller

population bases make it difficult to find, select, train and develop specialized combatant

resources like pilots and submariners.

Thus, it is crucial that new avenues be explored to circumvent this prevalent trend of

manpower shortages. One viable solution lies in exploiting technology and pushing the limits of

force multipliers. Within the domain of force multipliers, there lies a relatively new discipline,

unmanned warfare.

The definition of 'unmanned' chosen for this article is fairly loose, as the emphasis is not

solely on taking men out of machines but also on how to employ technology to make better use

of its manpower. Thus, while the focus is on unmanned warfare in its literal sense, the article will

also touch on some equipment or systems which result in lower manpower usage (or higher

operational capability with the same manning). In doing so, please accept that some aspects of

this article border on technological innovation as opposed to unmanned warfare per se.

DEPARTMENT OF ECE, AEC.


1.1 POTENTIAL OF UNMANNED WARFAREUnmanned warfare is a relatively new approach in the conduct of warfare, where the

boundaries are not well charted and limited largely by our imaginations. Unmanned warfare will

not only help overcome manpower and resource constraints but will also enhance operational

capabilities, since it can now move into areas where mankind has previously feared to tread.

With unmanned warfare, the competitive advantage can be swung such that human numerical

superiority is no longer an overwhelming advantage or a pre-requisite for victory.

1.2 NEED FOR UNMANNEDThe impetus to go unmanned include optimizing the deployment of manpower,

enhancing operational capabilities and being able to venture into territory once out-of-bounds to

mankind (e.g. deep ocean, space, etc). In particular, unmanned systems should be used to replace

humans where the work is dangerous, dirty or dull.

Some specific advantages in going unmanned include:

Reduction in manpower requirement: Developments in unmanned technology now

enables machines to perform tasks once undertaken by operators with equal if not better

precision. This direct substitution of manpower will lead to a corresponding reduction in

manpower needs.

Overcome fatigue and human error: Machines do not tire out as easily as men.

Operations that require constant alert or repetitive work over long durations are thus

potential areas where unmanned warfare can be profitably employed.

Minimize hazards: Risks to humans can be reduced as unmanned systems can take over

hazardous jobs previously done by human beings.



Cost savings: Besides manpower savings, there are also cost reductions in the form of

human cost (life) savings, training cost savings or even system cost savings as new

unmanned systems can enhance work flow and improve general work cycles.

Despite these advantages, there are several limitations which must be recognized and

reconciled. Some of the limitations include:

Decision making: Although unmanned systems are becoming increasingly sophisticated

and 'intelligent', it is still difficult to entrust machines with subjective decision making.

We must avoid careless delegation of responsibilities to technology that perform only

under programmed patterns.

Applicability: In certain areas and vocations, unmanned warfare acts merely as a catalyst

to facilitate achieving the ultimate goal. The claim that there is no victory until the

humble foot soldier occupies the objective is likely to remain valid for some time yet.

Diminution of esprit de corps: As manpower is increasingly scattered, we could witness

diminishing avenues for display of teamwork, leadership, valour and other human

qualities that make up a well trained and well-oiled armed force. This gradual 'erosion' of

values belonging to the profession of arms must be guarded against.

Department of Defense (DOD) Unmanned Ground Vehicles (UGV) save lives and

improve national defense capabilities by providing agencies of the Department of Defense

(DOD) with the control system architectures, advanced sensor systems, research services, and

standards to achieve autonomous mobility for unmanned ground vehicles.

1.3 UNMANNED GROUND VEHICLES (UGV)

Unmanned Ground Vehicles (UGV) are robotic platforms that are used as an extension of

human capability. This type of robot is generally capable of operating outdoors and over a wide

variety of terrain, functioning in place of humans.



UGVs have counterparts in aerial warfare (unmanned aerial vehicle) and naval warfare

(remotely operated underwater vehicles). Unmanned robotics is actively being developed for

both civilian and military use to perform dull, dirty, and dangerous activities. Some UGVs are

employed in War in Iraq.

There are two general classes of unmanned ground vehicles:

1. Tele-operated ones and

2. Autonomous ones.

An unmanned ground combat vehicle (UGCV) is an autonomous, all terrain unmanned

ground vehicle designed for combat.

1.3.1 TELE-OPERATED UGV:

A tele-operated UGV is a vehicle that is controlled by a human operator at a remote

location via a communications link. All cognitive processes are provided by the operator based

upon sensory feedback from either line-of-sight visual observation or remote sensory input such

as video cameras. A basic example of the principles of tele-operation would be a toy remote

control car. Each of the vehicles is unmanned and controlled at a distance via a wired or wireless

connection while the user provides all control based upon observed performance of the vehicle.

There are a wide variety of tele-operated UGVs in use today. Predominantly these

vehicles are used to replace humans in hazardous situations. Examples are warfare, explosives

and bomb disabling vehicles.

1.3.2 AUTONOMOUS UGV:

An autonomous UGV is essentially an autonomous robot but is specifically a vehicle that

operates on the surface of the ground.



A fully autonomous robot in the real world has the ability to:

Gain information about the environment.

Work for extended durations without human intervention.

Travel from point A to point B, without human navigation assistance.

Avoid situations that are harmful to people, property or itself, unless those are part of its

design specifications

Repair itself without outside assistance.

Detect objects of interest such as people and vehicles.

A robot may also be able to learn autonomously. Autonomous learning includes the ability

to:

Learn or gain new capabilities without outside assistance.

Adjust strategies based on the surroundings.

Adapt to surroundings without outside assistance.

Autonomous robots still require regular maintenance, as with all machines.



CHAPTER – 2

FUNCTIONAL DESCRIPTION

As mentioned in the introduction the unmanned warfare vehicles are either operated

autonomously or through tele-communications i.e., remote. The module constructed here is the

remote operated one. Through this remote the warfare vehicle is controlled to move in all

directions as well as firing of the gun. The remote is designed with control keys, micro-controller

and the RF transmitter. Out of these eight keys, four keys are used to control the warfare

vehicle’s direction i.e., to operate the in forward, backward, right and left directions. Two keys

are to switch ON and switch OFF the gun sound simulation IC that simulates that the bullets are

fired from the gun. Two keys are to adjust the gun direction upwards and downwards.

2.1 THE REMOTE CONTROL UNIT:

The remote control unit is nothing but the transmitter unit through which the warfare

vehicle is controlled. The main components present in this unit are the push buttons, micro

controller (89C2051), RF transmitter and a battery to provide power supply to all these

components. As mentioned earlier, a total of eight keys (push buttons) are used to control the

vehicle, and these are interfaced with the 89C2051 micro controller. Depending on the key

pressed, the controller generates a unique code which is fed to the RF transmitter for modulation.

The detailed explanation about the RF transmitter is provided below.

Radio frequency (RF) transmitters are widely used in radio frequency communications

system. With the increasing availability of efficient, low cost electronic modules, mobile

communication system are becoming more and more widespread.



A terminal apparatus used in the radio communications system receives a radio frequency

signal transmitted from a base station, by an antenna, inputs the signal to a receiving radio-

frequency unit via an antenna duplexer, high frequency amplifies the signal, removes

unnecessary waves outside the receiving band from the signal, converts the signal to an

intermediate frequency signal, demodulates the intermediate frequency signal by a demodulator,

and converts the signal into a base band signal.

Generally, a radio transmitter is used for performing a radio transmission operation,

whereby a high frequency signal is outputted from a modulator is transmitted to an antenna of

the radio transmitter and is transmitted there from to a remote radio transmitter thereby a signal

is transmitted.

The transmitting base band signal is subjected to a predetermined signal process, input to

a modulator, which modulates a carrier wave signal. The modulated carrier wave signal is

converted into a radio frequency by a transmitting radio-frequency circuit and amplified to a

predetermined transmitting power, and transmitted to the base station from the antenna via the

duplexer. Communication systems are known to support wireless and wire lined communications

between wireless and /or wire lined communication devices.

The function of a radio frequency (RF) transmitter is to modulate, up convert, and

amplify signals for transmission into free space. An RF transmitter generally includes a

modulator that modulates an input signal and a radio frequency power amplifier that is coupled

to the modulator to amplify the modulated input signal. The radio frequency power amplifier is

coupled to an antenna that transmits the amplified modulated input signal. Power amplifiers are

required in radio telecommunication system to amplify signals before transmitting, because a

radio signal attenuates on the radio path.



Fig. 2.1 Block Diagram of Vehicle Control Station



Fig. 2.2 Remote Control Circuit

2.1.1 Transmitter unit

For efficiently, the amplifier is often a non-linear amplifier operated near its peak

capacity. To avoid distortion of the transmitted signals due to the non-linearity, the signals are

pre-distorted by a pre-distorter before they are transmitted. The pre-distortion is required to

prevent transmitter from transmitting signals on channel bands other than the band assigned to



the transmitter. The pre-distortion values are chosen such that the product values entering the

power amplifier will be distorted by the power amplifier to return to a substantially linear

amplification of the modulated signals.

A direct conversion transmitter system to produce a transmission signal is generally

comprised of a low oscillator (LO), a phase locked loop (PLL), a quadarature generator, a

modulator, a power amplifier (PA), and one or more filters. The low oscillator, coupled to the

PLL, produces a signal with a frequency that is substantially equal to the frequency of a desired

RF transmission signal. The quadarature generator is coupled to the low oscillator and the

modulator.

The PA is coupled to the quadarature generator, and receives the transmission signal and

amplifies it. The amplified signal may go through a filter to reduce noise or spurious outputs

outside of the transmission band. High quality RF transmitters typically include band pass filters;

such as surface acoustic wave (SAW) filters provide excellent performance.

A typical system may employ a band pass filter following the power amplifier to reduce

undesired noise present at the antenna in different portion of RF spectrum to meet various

standards regulations and specifications.

Pin description of Transmitter

Pin 1: Ground (-5V)

Pin 2: input pin for data from encoder

Pin3: supply (+5V)

Pin4: pin for external RF antenna



Fig.2.3 Pin diagram of Transmitter

2.2 THE WARFARE VEHICLE UNIT

This unit consists of RF receiver, micro controller (89C51), H-bridge IC (L293D), relays,

gun sound simulator IC (UM3561), 3 DC motors and a battery for providing power supply to all

these devices.

Depending on the keys pressed from the remote, the data is modulated and transmitted by

the RF transmitter, which will be demodulated by the RF receiver present on the warfare vehicle

and is fed to the 89C51 micro controller. The controller decodes the data and takes the necessary

action depending on the program written in it. Thus whenever we find the enemies, through the

gun can target the point and fire. The vehicle movement can be controlled with the DC motors

that will be interfaced to the controller through the H-bridge IC L293D. By using this IC we will

be able to drive 2 DC motors and for the movement of the gun one more DC motor is used that

will be operated through the relays by the controller.



Fig. 2.4 Block Diagram of Warfare Vehicle



Fig.2.5 Receiver Circuit

2.2.1 Receiver Unit



Receivers for communication systems generally are designed such that they are tuned to

receive one of a multiplicity of signals having widely varying bandwidths and which may fall

within a particular frequency range.

The RF receiver receives an RF signal, converts the RF signal to an IF signal, and then

converts the IF signal to a base band signal, which it then provides to the base band processor.

As is also known, RF transceivers typically include sensitive components susceptible to noise

and interference with one another and with external sources.

The RF receiver is coupled to the antenna and includes a low noise amplifier, one or

more intermediate frequency stages, a filtering stage, and a data recovery stage. The low noise

amplifier receives an inbound RF signal via the antenna and amplifies it.

The one or more intermediate frequency stages mix the amplified RF signal with one or

more local oscillations to convert the amplified RF signal into a base band signal or an

intermediate frequency (IF) signal.

Fig.2.6 Pin diagram of receiver



Pin 1: ground (-5V)

Pin 2: output pin for digital data received

Pin 3: output pin for analog data received

Pin 4: supply (+5V)

Pin 6 & 7: ground (-5V)

Pin 8: pin for external RF Antenna

Fig.2.7 Receiver chip

2.2.2 L293D “H” BRIDGE

In this project, the dual H-bridge motor driver IC used is L293D. “The L293D is a

monolithic integrated, high voltage, high current, 4-channel driver”. The L293D supports two

DC motors. Pin 8 is voltage for the motors and pin 16 is the +5 voltage for the chip. So with one

IC we can interface two DC motors which can be controlled in both clockwise and counter

clockwise direction and if you have motor with fix direction of motion then we can make use of

all the four I/Os to connect up to four DC motors. First motor is connected between pin 3 and 6.

The motor is turned on by sending a high signal to both the enable (pin 1) pin and one of the two

direction pins, i.e. pin 2 or pin 7. To stop motor, the enable pin is high and both pin 2 and pin 7

are low. L293D has output current of 600mA and peak output current of 1.2A per channel.



Moreover for protection of circuit from back EMF output diodes are included within the IC. The

output supply (VCC2) has a wide range from 4.5V to 36V, which had made L293D a best choice

for DC motor driver.

Fig.2.8 DC Motor Control with H-Bridge

The same goes for the other side of the chip. When using two motors, the best practice is

to connect pins 2 and 15 togather and pin 7 and 10. above figure shows the control of the DC

motors with L293D and microcontroller signal.

Fig. 2.9. L293D H Bridge (Motor Driver)



Motor drivers are the simplest modules that provide power amplification for low-level

control singals like PWM and direction supplied by the user.

Depending on the input signals given from the remote, the controller decodes the

information and takes decisions appropriately. The DC motor is also to be rotated in the reverse

direction and by reversing the polarities, the motor rotates in the reverse direction that is done by

the controller through the H - Bridge IC.

2.2.3 DC Motor

Permanent magnet DC motor responds to both voltage and current. The steady state voltage

across a motor determines the motor’s running speed, and the current through its armature

windings determines the torque. Apply a voltage and the motor will start running in one

direction; reverse the polarity and the direction will be reversed. If you apply a load to the motor

shaft, it will draw more current, if the power supply does not able to provide enough current, the

voltage will drop and the speed of the motor will be reduced. However, if the power supply can

maintain voltage while supplying the current, the motor will run at the same speed. In general,

you can control the speed by applying the appropriate voltage, while torque is controlled by

current. In most cases, DC motors are powered up by using fixed DC power supply, therefore; it

is more efficient to use a chopping circuit.

Consider what happens when a voltage applied to a motor’s windings is rapidly turned

ON and OFF in such a way that the frequency of the pulses produced remains constant, but the

width of the ON pulse is varied. This is known as Pulse Width Modulation (PWM). Current only

flows through the motor during the ON portion of the PWM waveform. If the frequency of the

PWM input is high enough, the mechanical inertia of the motor cannot react to the ripple wave;

instead, the motor behaves as if the current were the DC average of the ripple wave. Therefore,

by changing the width of pulse, we can control the motor speed.


http://engknowledge.com/documents/definitions_P.htm#pwm

http://engknowledge.com/documents/definitions_P.htm#pwm

http://engknowledge.com/power_supply_design.aspx

http://engknowledge.com/documents/definitions_D.htm#DC

http://engknowledge.com/power_supply_design.aspx

http://engknowledge.com/documents/definitions_D.htm#DC


At the most basic level, electric motors exist to convert electrical energy into mechanical

energy. This is done by way of two interacting magnetic fields -- one stationary, and another

attached to a part that can move. A number of types of electric motors exist, but most BEAM

bots use DC motors in some form or another. DC motors have the potential for very high torque

capabilities (although this is generally a function of the physical size of the motor), are easy to

miniaturize, and can be "throttled" via adjusting their supply voltage. DC motors are also not

only the simplest, but the oldest electric motors.

2.2.4 POWER SOURCE:

To generate required power source to drive the vehicle 12V, 1.2 AH, rechargeable, lead

acid heavy duty battery is used. Here we required two different DC levels of +5V & +12V, the

battery as it is delivering 12V is used to drive the DC motors and H Bridge, where as for the

remaining electronic circuitry consists of microcontroller and rest of the circuit requires +5V

constant source. To generate a stable supply of +5V, 7805 three terminal voltage regulator chip

is used which provides constant supply, though the battery terminal voltage falls down to 8V.

The DC motors are designed to operate at 12V DC and each motor consumes a maximum current

of 150 milli-amps, there by two motors together consumes 300 milli-amps, the remaining

circuitry including microcontroller will consume another 150 milli-amps, hence the entire system

consumes around 450 milli-amps approximately. The battery backup time = battery rating /

consumed energy.

Fig. 2.10 Battery Charger Circuits


http://encyclobeamia.solarbotics.net/articles/dc.html

http://encyclobeamia.solarbotics.net/articles/torque.html




2.2.5 RELAY

A Relay is a device that opens or closes an auxiliary circuit under some pre-determined condition

in the Main circuit. The object of a Relay is generally to act as a sort of electric magnifier, that is

to say, it enables a comparatively week current to bring in to operation on a much stronger

current. It also provides complete electrical isolation between the controlling circuit and the

Controlled circuit.

Specifications:

(1) Coil resistance : 100Ω to 500Ω

(2) Operating voltage : 6V to 24V DC

(3) No. of contacts : 1 to 4 change over

(4) Contact current Rating : 1.5 to 25 Amps



Fig. 2.11 Relay

CHAPTER – 3

BRIEF DESCRIPTION ABOUT RF COMMUNICATIONS

Radio Frequency (RF) and wireless have been around for over a century with Alexander

Popov and Sir Oliver Lodge laying the groundwork for Guglielmo Marconi’s wireless radio

developments in the early 20th century. In December 1901, Marconi performed his most

prominent experiment, where he successfully transmitted Morse code from Cornwall, England,

to St John’s, Canada.

3.1 General physics of radio signals

RF communication works by creating electromagnetic waves at a source and being able

to pick up those electromagnetic waves at a particular destination. These electromagnetic waves

travel through the air at near the speed of light. The wavelength of an electromagnetic signal is

inversely proportional to the frequency; the higher the frequency, the shorter the wavelength.



Frequency is measured in Hertz (cycles per second) and radio frequencies are measured

in kilohertz (KHz or thousands of cycles per second), megahertz (MHz or millions of cycles per

second) and gigahertz (GHz or billions of cycles per second). Higher frequencies result in shorter

wavelengths. The wavelength for a 900 MHz device is longer than that of a 2.4 GHz device.

In general, signals with longer wavelengths travel a greater distance and penetrate

through, and around objects better than signals with shorter wavelengths.

3.2 What is RF?

RF itself has become synonymous with wireless and high frequency signals, describing

anything from AM radio between 535 kHz and 1605 kHz to computer local area networks

(LANs) at 2.4 GHz. However, RF has traditionally defined frequencies from a few kHz to

roughly 1 GHz. If one considers microwave frequencies as RF, this range extends to 300 GHz.

Radio frequency (RF) is a frequency, or rate of oscillation, of electromagnetic radiation within

the range of about 3 Hz to 300 GHz. This range corresponds to the frequency of alternating

current electrical signals used to produce and detect radio waves. Since most of this range is

beyond the vibration rate that most mechanical systems can respond to, RF usually refers to

oscillations in electrical circuits. The following tables outline the various nomenclatures for the

frequency bands.

3.3 Frequency Band Designations:

Name Symbol Frequency Wavelength Applications

Extremely low

frequencyELF 3–30 Hz 100–10 Mm

Directly audible when converted to

sound (above ~20 Hz),

communication with submarines



Super low

frequencySLF 30–300 Hz 10–1 Mm


sound, AC power grids (50–60 Hz)

Ultra low

frequencyULF 300–3000 Hz 1000–100 km


sound, communication within mines

Very low

frequencyVLF 3–30 kHz 100–10 km


sound (below ~20 kHz; or ultrasound

otherwise)

Low frequency LF 30–300 kHz 10–1 kmAM broadcasting, navigational

beacons, and amateur radio.

Medium

frequencyMF 300–3000 kHz 1000–100 m

Navigational beacons, AM

broadcasting, amateur radio,

maritime and aviation

communication

High frequency HF 3–30 MHz 100–10 mShort wave, amateur radio, citizens'

band radio, sky wave propagation.

Very high

frequencyVHF 30–300 MHz 10–1 m

FM broadcasting, amateur radio,

broadcast television, aviation, GPR,

MRI.

Ultra high

frequencyUHF 300–3000 MHz 100–10 cm

Broadcast television, amateur radio,

mobile telephones, cordless

telephones, wireless networking,

remote keyless entry for automobiles,

microwave ovens, GPR

Super high SHF 3–30 GHz 10–1 cm Wireless networking, satellite links,



frequencyamateur radio, microwave links,

satellite television, door openers

Extremely high

frequencyEHF 30–300 GHz 10–1 mm

Microwave data links, radio

astronomy, amateur radio, remote

sensing, advanced weapons systems,

advanced security scanning

The above Table shows a relationship between frequency (f) and wavelength (λ). A wave

or sinusoid can be completely described by either its frequency or its wavelength. They are

inversely proportional to each other and related to the speed of light through a particular

medium. The relationship in a vacuum is shown in the following equation:

Where c is the speed of light. As frequency increases, wavelength decreases. For

reference, a 1 GHz wave has a wavelength of roughly 1 foot, and a 100 MHz wave has a

wavelength of roughly 10 feet.

RF measurement methodology can generally be divided into three major categories:

spectral analysis, vector analysis, and network analysis. Spectrum analyzers, which provide basic

measurement capabilities, are the most popular type of RF instrument in many general-purpose



applications. Specifically, using a spectrum analyzer you can view power-vs. -Frequency

information, and can sometimes demodulate analog formats, such as amplitude modulation

(AM), frequency modulation (FM), and phase modulation (PM).

Vector instruments include vector or real-time signal analyzers and generators. These

instruments analyze and generate broadband waveforms, and capture time, frequency, phase, and

power information from signals of interest. These instruments are much more powerful than

spectrum analyzers and offer excellent modulation control and signal analysis.

Network analyzers, on the other hand, are typically used for making S-parameter

measurements and other characterization measurements on RF or high-frequency components.

Network analyzers are instruments that correlate both the generation and analysis on multiple

channels but at a much higher price than spectrum analyzers and vector signal

generators/analyzers.

3.4 Working of RF communication system

Imagine an RF transmitter wiggling an electron in one location. This wiggling electron

causes a ripple effect, somewhat a kind of dropping a pebble in a pond. The effect is an

electromagnetic (EM) wave that travels out from the initial location resulting in electrons

wiggling in remote locations. An RF receiver can detect this remote electron wiggling.

The RF communication system then utilizes this phenomenon by wiggling electrons in a

specific pattern to represent information. The receiver can make this same information available

at a remote location; communicating with no wires.

In most wireless systems, a designer has two overriding constraints: it must operate over

a certain distance (range) and transfer a certain amount of information within a time frame (data

rate). Then the economics of the system must work out (price) along with acquiring government

agency approvals (regulations and licensing).



3.5 Radio communication

In order to receive radio signals, for instance from AM/FM radio stations, a radio antenna

must be used. However, since the antenna will pick up thousands of sine waves at a time, a radio

tuner is necessary as well to tune in to a particular frequency (or frequency range). This is

typically done via a resonator (in its simplest form, a circuit with a capacitor and an inductor).

The resonator is configured to resonate at a particular frequency (or frequency band), thus

amplifying sine waves at that radio frequency, while ignoring other sine waves. Usually, either

the inductor or the capacitor of the resonator is adjustable, allowing the user to change the

frequency it resonates at.

CHAPTER – 4

DESCRIPTION ABOUT ‘H’ - BRIDGE

4.1 Introduction

Whenever a robotics hobbyist talk about making a robot, the first thing comes to his mind

is making the robot move on the ground. And there are always two options in front of the

designer whether to use a DC motor or a stepper motor. When it comes to speed, weight, size,

and cost... DC motors are always preferred over stepper motors. There are many things, which

we can do with DC motor when interfaced with a micro controller. For example we can control

the speed of motor, we can control the direction of rotation, we can also do encoding of the

rotation made by DC motor i.e. keeping track of how many turns are made by the motors etc. So

we can see DC motors are better than stepper motors.


http://www.8051projects.net/dc-motor-interfacing/introduction.php


In this part of tutorial we will learn to interface a DC motor with a micro controller.

Usually H-bridge is preferred way of interfacing a DC motor. These days many IC

manufacturers have H-bridge motor drivers available in the market like L293D is most used H-

Bridge driver IC. H-bridge can also be made with the help of transistors and MOSFET’s etc.

rather of being cheap, they only increase the size of the design board, which is sometimes not

required so using a small 16 pin IC is preferred for this purpose. L293D is having two ‘H’

Bridges inside, so that we can drive two DC motors simultaneously. Before discussing about this

device, first we must learn basic theory of ‘H’ Bridges. The following is the description.

4.2 Basic Theory

Fig. 4.1 H-Bridge using DC motor

Let's start with the name, H-bridge. Sometimes called a "full bridge" the H-bridge is so

named because it has four switching elements at the "corners" of the H and the motor forms the

cross bar. The basic bridge is shown in the figure above. The key fact to note is that there are, in

theory, four switching elements within the bridge. These four elements are often called, high side

left, high side right, low side right, and low side left (when traversing in clockwise order).



The switches are turned on in pairs, either high left and lower right, or lower left and high

right, but never both switches on the same "side" of the bridge. If both switches on one side of a

bridge are turned on it creates a short circuit between the battery plus and battery minus

terminals. If the bridge is sufficiently powerful it will absorb that load and your batteries will

simply drain quickly. Usually however the switches in question melt.

To power the motor, turn on two switches that are diagonally opposed. The current flows

and the motor begin to turn in a "positive" direction. Switch off these two switches and switch on

other two switches diagonally in other direction then the motor starts rotating in opposite

direction. Actually it is quite simple, the tricky part comes in when we decide what to use for

switches. Anything that can carry a current will work, from four SPST switches, one DPDT

switch, relays, transistors, to enhancement mode power MOSFET’s.

One more topic in the basic theory section is quadrants. If each switch can be controlled

independently then we can do some interesting things with the bridge, some folks call such a

bridge a "four quadrant device" (4QD). If we built it out of a single DPDT relay, we can really

only control forward or reverse. We can build a small truth table that tells us for each of the

switch's states, what the bridge will do. As each switch has one of two states, and there are four

switches, there are 16 possible states. However, since any state that turns both switches on one

side on is "bad", there are in fact only four useful states (the four quadrants) where the transistors

are turned on.

High Side Left High Side Right Low Side Left Low Side Right Quadrant Description

On Off Off On Forward Running

Off On On Off Backward Running

On On Off Off Braking

Off Off On On Braking



In the above table the last two rows describes condition about short circuit the motor that

causes the motors generator effect to work against it. The turning motor generates a voltage,

which tries to force the motor to turn the opposite direction. This causes the motor to rapidly stop

spinning and is called "braking" on a lot of H-bridge designs. Of course there is also the state

where all the transistors are turned off. In this case the motor coasts freely if it was spinning and

does nothing if it was doing nothing.

4.2.1 Using Relays:

A simple implementation of a H Bridge using four SPST relays is shown. Terminal A is

High Side Left, Terminal B is High Side Right, Terminal C is Low Side Left and Terminal D is

Low Side Right. The logic followed is according to the table above.

Warning: Never turn on A and C or B and D at the same time. This will lead to a short circuit

of the battery and will lead to failure of the relays due to the large current.

Fig. 4.2 H-Bridge Using Relays



4.2.2 Using Transistors:

We can better control our motor by using transistors or Field Effect Transistors (FET’s).

Most of what we have discussed about the relays H-Bridge is true of these circuits. See the

diagram showing how they are connected. We should add diodes across the transistors to catch

the back voltage that is generated by the motor's coil when the power is switched on and off.

This fly back voltage can be many times higher than the supply voltage.

Don't turn on A and C or B and D at the same time.

Fig. 4.3 H-Bridge Using Transistors

Transistors, being a semiconductor device, will have some resistance, which causes them

to get hot when conducting much current. This is called not being able to sink or source very

much power, i.e.: Not able to provide much current from ground or from plus voltage.



MOSFET’s are much more efficient, they can provide much more current and not get as

hot. They usually have the fly back diodes built in so we don't need the diodes anymore. This

helps guard against fly back voltage frying our ICs.

To use MOSFET’s in an H-Bridge, we need P-Channel MOSFET’s on top because they

can "source" power and N-Channel MOSFET’s on the bottom because they can "sink" power. It

is important that the four quadrants of the H-Bridge circuits be turned on and off properly. When

there is a path between the positive and groundside of the H-Bridge, other than through the

motor, a condition exists called "shoot through". This is basically a direct short of the power

supply and can cause semiconductors to become ballistic, in circuits with large currents flowing.

There are H-bridge chips available that are much easier, and safer, to use than designing our own

H-Bridge circuit.

4.3 L293D Dual H-Bridge Motor Driver

L293D is a dual H-Bridge motor driver, so with one IC we can interface two DC motors,

which can be controlled in both clockwise and counter clockwise directions. Since the device is

having four half ‘H’ Bridges, thereby if required four motors can be driven through this single

device, moreover the task is to run all four motors in one direction only. L293D has output

current of 600mA and peak output current of 1.2A per channel. Moreover for protection of

circuit from back EMF output diodes are included within the IC. The output supply (VCC2) has

a wide range from 4.5V to 36V, which has made L293D a best choice for DC motor driver.

In this IC there are two different power supplies (Vcc1 and Vcc2). Vcc1 is for logic input

circuit while Vcc2 is supply for the output circuit. This means that we should apply about 5V to

Vcc1 and whatever voltage required by the motor (up to 36V max for this IC) to Vcc2. Each

Half H-Bridge has an individual Ground. So we must ground the terminal corresponding to the


http://www.8051projects.net/dc-motor-interfacing/l293d-interfacing-with-microcontroller.php


Half H-Bridge, depending up on the circuit design, if required all four terminals of bridges can

be connected to the ground.

Each Half H-Bridge has an Input (A) and output (Y). Also there are enable pins to turn on

the Half H-Bridges. Once a Half H-bridge is enabled, then the truth table is as follows:

INPUTA

OUTPUTY

L L

H H

So we just give a High level when we want to turn the Half H-Bridge on and Low level

when we want to turn it off. When the Half H-Bridge is on, the voltage at the output is equal to

Vcc2.

If we want to make a Full H-Bridge, we must connect the motor (or the load) between the

outputs of two Half H-Bridges and the inputs will be the two inputs of the Half H-Bridges.

Suppose we have connected Half H-Bridges 1 and 2 to form a Full H-Bridge. Now the

truth table is as follows:

INPUT

1A

INPUT

2A

OUTPUT

1Y

OUTPUT

2YDescription

L L L LBraking (both terminals of motor are

Gnd)

L H L H Forward Running



H L H L Backward Running

H H H HBraking (both terminals of motor at

Vcc2)



CHAPTER – 5

DC MOTORS – AN OVERVIEW

At the most basic level, electric motors exist to convert electrical energy into mechanical

energy. This is done by way of two interacting magnetic fields -- one stationary, and another

attached to a part that can move. A number of types of electric motors exist, but most BEAM

bots use DC motors in some form or another. DC motors have the potential for very high torque

capabilities (although this is generally a function of the physical size of the motor), are easy to

miniaturize, and can be "throttled" via adjusting their supply voltage. DC motors are also not

only the simplest, but the oldest electric motors.

The basic principles of electromagnetic induction were discovered in the early 1800's by

Oersted, Gauss, and Faraday. By 1820, Hans Christian Oersted and Andre Marie Ampere had

discovered that an electric current produces a magnetic field. The next 15 years saw a flurry of

cross-Atlantic experimentation and innovation, leading finally to a simple DC rotary motor. A

number of men were involved in the work, so proper credit for the first DC motor is really a

function of just how broadly you choose to define the word "motor."

DC motors are configured in many types and sizes, including brushless, servo, and gear

motor types. A motor consists of a rotor and a permanent magnetic field stator. The magnetic

field is maintained using either permanent magnets or electromagnetic windings. DC motors are

most commonly used in variable speed and torque applications.

Brushed DC motors have built-in commutation, meaning that as the motor rotates,

mechanical brushes automatically commutate coils on the rotor. Brushless DC motors use an

external power drive to allow commutation of the coils on the stator. Brush-type motors are used

when cost is a priority, while brushless motors are selected fulfill specific requirements, such as

maintenance-free operation, high speeds, and hazardous environments where sparking could be

dangerous.


http://www.globalspec.com/datasheets/17/areaspec/type4_gearmotor

http://www.globalspec.com/datasheets/17/areaspec/type4_gearmotor

http://www.globalspec.com/datasheets/17/areaspec/type0_dc_brushless



http://encyclobeamia.solarbotics.net/articles/current.html


http://encyclobeamia.solarbotics.net/articles/torque.html




DC gear motors are configured in many types and sizes, including brushless and servo. A

DC gear motor consists of a rotor and a permanent magnetic field stator and an integral gearbox

or gear head. The magnetic field is maintained using either permanent magnets or

electromagnetic windings. DC motors are most commonly used in variable speed and torque

applications.

Motion and controls covers a wide range of components that in some way are used to

generate and/or control motion. Areas within this category include bearings and bushings,

clutches and brakes, controls and drives, drive components, encoders and resolvers, Integrated

motion control, limit switches, linear actuators, linear and rotary motion components, linear

position sensing, motors (both AC and DC motors), orientation position sensing, pneumatics and

pneumatic components, positioning stages, slides and guides, power transmission (mechanical),

seals, slip rings, solenoids, springs.

Motors are the devices that provide the actual speed and torque in a drive system. This

family includes AC motor types (single and multiphase motors, universal, servo motors,

induction, synchronous, and gear motor) and DC motors (brushless, servo motor, and gear

motor) as well as linear, stepper and air motors, and motor contactors and starters.

Permanent magnet DC motor responds to both voltage and current. The steady state

voltage across a motor determines the motor’s running speed, and the current through its

armature windings determines the torque. Apply a voltage and the motor will start running in one

direction; reverse the polarity and the direction will be reversed. If you apply a load to the motor

shaft, it will draw more current, if the power supply does not able to provide enough current, the

voltage will drop and the speed of the motor will be reduced. However, if the power supply can

maintain voltage while supplying the current, the motor will run at the same speed. In general,

you can control the speed by applying the appropriate voltage, while torque is controlled by

current. In most cases, DC motors are powered up by using fixed DC power supply, therefore; it

is more efficient to use a chopping circuit.



Consider what happens when a voltage applied to a motor’s windings is rapidly turned

ON and OFF in such a way that the frequency of the pulses produced remains constant, but the

width of the ON pulse is varied. This is known as Pulse Width Modulation (PWM). Current only

flows through the motor during the ON portion of the PWM waveform. If the frequency of the

PWM input is high enough, the mechanical inertia of the motor cannot react to the ripple wave;

instead, the motor behaves as if the current were the DC average of the ripple wave. Therefore,

by changing the width of pulse, we can control the motor speed.

5.1 Principles of operation

In any electric motor, operation is based on simple electromagnetism. A current-carrying

conductor generates a magnetic field; when this is then placed in an external magnetic field, it

will experience a force proportional to the current in the conductor, and to the strength of the

external magnetic field. As you are well aware of from playing with magnets as a kid, opposite

(North and South) polarities attract, while like polarities (North and North, South and South)

repel. The internal configuration of a DC motor is designed to harness the magnetic interaction

between a current-carrying conductor and an external magnetic field to generate rotational

motion.

Let's start by looking at a simple 2-pole DC electric motor (here red represents a magnet

or winding with a "North" polarization, while green represents a magnet or winding with a

"South" polarization).



Fig. 5.1 DC Motor

Every DC motor has six basic parts -- axle, rotor (a.k.a., armature), stator, commutator,

field magnet(s), and brushes. In most common DC motors (and all that Beamers will see), the

external magnetic field is produced by high-strength permanent magnets1. The stator is the

stationary part of the motor -- this includes the motor casing, as well as two or more permanent

magnet pole pieces. The rotor (together with the axle and attached commutator) rotates with

respect to the stator. The rotor consists of windings (generally on a core), the windings being

electrically connected to the commutator. The above diagram shows a common motor layout --

with the rotor inside the stator (field) magnets.

The geometry of the brushes, commutator contacts, and rotor windings are such that

when power is applied, the polarities of the energized winding and the stator magnet(s) are

misaligned, and the rotor will rotate until it is almost aligned with the stator's field magnets. As

the rotor reaches alignment, the brushes move to the next commutator contacts, and energize the

next winding. Given our example two-pole motor, the rotation reverses the direction of current

through the rotor winding, leading to a "flip" of the rotor's magnetic field, driving it to continue

rotating.



In real life, though, DC motors will always have more than two poles (three is a very

common number). In particular, this avoids "dead spots" in the commutator. You can imagine

how with our example two-pole motor, if the rotor is exactly at the middle of its rotation

(perfectly aligned with the field magnets), it will get "stuck" there. Meanwhile, with a two-pole

motor, there is a moment where the commutator shorts out the power supply (i.e., both brushes

touch both commutator contacts simultaneously). This would be bad for the power supply, waste

energy, and damage motor components as well. Yet another disadvantage of such a simple motor

is that it would exhibit a high amount of torque "ripple" (the amount of torque it could produce is

cyclic with the position of the rotor).



CHAPTER – 6

DESCRIPTION ABOUT MICROCONTROLLERS

A Micro controller consists of a powerful CPU tightly coupled with memory, various I/O

interfaces such as serial port, parallel port timer or counter, interrupt controller, data acquisition

interfaces-Analog to Digital converter, Digital to Analog converter, integrated on to a single

silicon chip. If a system is developed with a microprocessor, the designer has to go for external

memory such as RAM, ROM, EPROM and peripherals.

But controller is provided all these facilities on a single chip. Development of a Micro

controller reduces PCB size and cost of design. One of the major differences between a

Microprocessor and a Micro controller is that a controller often deals with bits not bytes as in the

real world application.

6.1 NECESSITY OF MICROCONTROLLERS

Microprocessors brought the concept of programmable devices and made many

applications of intelligent equipment. Most applications, which do not need large amount of data

and program memory, tended to be costly.

The microprocessor system had to satisfy the data and program requirements so;

sufficient RAM and ROM are used to satisfy most applications .The peripheral control

equipment also had to be satisfied. Therefore, almost all-peripheral chips were used in the

design. Because of these additional peripherals cost will be comparatively high.

6.2 ADVANTAGES OF MICROCONTROLLERS

1. If system is developed with a microprocessor, the designer has to go for external memory such

as RAM, ROM or EPROM and peripherals and hence the size of PCB will be large enough to

hold all the required peripherals. But, the micro controller has got all this peripheral facility on a



single chip o development of a similar system with a micro controller reduces PCB size and cost

of the design.

2. One of the major differences between a micro controller and a microprocessor is that a

controller often deals with bits, not bytes as in the real world application, for example switch

contacts can only be open or close, indicators should be lit or dark and motors can be either

turned on or off and so forth.

Now we may be wondering about the non-mentioning of memory space meant for

the program storage, the most important part of any embedded controller. Originally this

8051 architecture was introduced with on-chip, ‘one time programmable’ version of

Program Memory of size 4K X 8.

Intel delivered all these microcontrollers (8051) with user’s program fused inside

the device. The memory portion was mapped at the lower end of the Program Memory

area. But, after getting devices, customers couldn’t change anything in their program

code, which was already made available inside during device fabrication.

6.3 FEATURES OF 8051 MICROCONTROLLER

The following are the features of 8051 micro controllers

1. Eight – bit CPU with registers

2. 16 – bit program counter and data pointer

3. 8 – bit program status word

4. 8 – bit stack pointer

5. Internal ROM or EPROM (4k)

6. Internal RAM of 128 bites



7. Four register banks, each containing eight registers

8. 16 bytes, which may be addressed at the bit level

9. 80 bytes of general purpose data memory

10. 32 input / output pins arranged as four 8 – bit ports

11. Two sixteen bit timer / counter

12. Full duplex serial data receiver / transmitter

13. Two external and three internal interrupt sources

14. Oscillator and clock circuits

15. Control registers

6.4 PIN DIAGRAM OF 89C51 MICROCONTROLLER



Fig. 6.1 Pin Diagram Of 89c51 Microcontroller

6.5 FUNCTIONAL BLOCK DIAGRAM OF MICROCONTROLLER



Fig. 6.2 Functional block diagram of micro controller

6.5.1 The 8051 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.



Fig. 6.3 Oscillator and timing circuit6.5.2 I/O Ports

One major feature of a microcontroller is the versatility built into the input/output (I/O)

circuits that connect the 8051 to the outside world. The main constraint that limits numerous

functions is the number of pins available in the 8051 circuit. The DIP had 40 pins and the

success of the design depends on the flexibility incorporated into use of these pins. For this

reason, 24 of the pins may each used for one of the two entirely different functions which

depend, first, on what is physically connected to it and, then, on what software programs are used

to “program” the pins.

Port 0

Port 0 pins may serve as inputs, outputs, or, when used together, as a bi directional low-

order address and data bus for external memory. To configure a pin as input, 1 must be written

into the corresponding port 0 latch by the program. When used for interfacing with the external

memory, the lower byte of address is first sent via PORT0, latched using Address latch enable

(ALE) pulse and then the bus is turned around to become the data bus for external memory.

Port 1



Port 1 is exclusively used for input/output operations. PORT 1 pins have no dual function.

When a pin is to be configured as input, 1 is to be written into the corresponding Port 1 latch.

Port 2

Port 2 maybe used as an input/output port. It may also be used to supply a high –order

address byte in conjunction with Port 0 low-order byte to address external memory. Port 2 pins

are momentarily changed by the address control signals when supplying the high byte a 16-bit

address. Port 2 latches remain stable when external memory is addressed, as they do not have to

be turned around (set to 1) for data input as in the case for Port 0.

Port 3

Port 3 may be used to input /output port. The input and output functions can be

programmed under the control of the P3 latches or under the control of various special function

registers. Unlike Port 0 and Port 2, which can have external addressing functions and change all

eight-port b se, each pin of port 3 maybe individually programmed to be used as I/O or as one of

the alternate functions. The Port 3 alternate uses are:

Port 3 Alternate Uses

Pin (SFR) Alternate Use

P3.0-RXD (SBUF) Serial data input

P3.1-TXD (SBUF) Serial data output

P3.2-INTO 0 (TCON.1) External interrupt 0

P3.3 - INTO 1 (TCON.3) External interrupt 1

P3.4 - T0 (TMOD) External Timer 0 input

P3.5 – T1 (TMOD) External timer 1 input



P3.6 - WR External memory write pulse

P3.7 - RD External memory read pulse

6.5.3 Memory unit

Memory is part of the micro controller whose function is to store data. The easiest way

to explain it is to describe it as one big closet with lots of drawers. If we suppose that we marked

the drawers in such a way that they cannot be confused, any of their contents will then be easily

accessible. It is enough to know the designation of the drawer and so we will know its contents

for sure.

Memory components are exactly like that. For a certain input we get the contents of a

certain addressed memory location and that’s all. Two new concepts are brought to us:

addressing and memory location. Memory consists of all memory locations, and addressing is

nothing but selecting one of them. This means that we need to select the desired memory

location on one hand, and on the other hand we need to wait for the contents of that location.

Besides reading from a memory location, memory must also provide for writing onto it.

Supplying an additional line called control line does this. We will designate this line as R/W

(read/write). Control line is used in the following way: if r/w=1, reading is done, and if opposite

is true then writing is done on the memory location. Memory is the first element, and we need a

few operation of our micro controller.

6.5.4 Central Processing Unit

Let add 3 more memory locations to a specific block that will have a built in capability to

multiply, divide, subtract, and move its contents from one memory location onto another. The

part we just added in is called “central processing unit” (CPU). Its memory locations are called

registers.



Registers are therefore memory locations whose role is to help with performing various

mathematical operations or any other operations with data wherever data can be found. Look at

the current situation. We have two independent entities (memory and CPU), which are

interconnected, and thus any exchange of data is hindered, as well as its functionality. If, for

example, we wish to add the contents of two memory locations and return the result again back

to memory, we would need a connection between memory and CPU. Simply stated, we must

have some “way” through data goes from one block to another.

6.5.5 Program Status Word

The PSW register contains program status information as detailed in Table below: The

PSW consists of math flags, user program flag F0, and the register bank select bits that identify

which of the four general register banks is currently in use by the program.

6.5.6 Stack Pointer

The Stack Pointer register is 8 bits wide. It is incremented before data is stored during

PUSH and CALL executions. While the stack may reside anywhere in on-chip RAM, the Stack

Pointer is initialized to 07H after a reset. This causes the stack to begin at locations 08H.

6.5.7 Data Pointer:

The Data Pointer (DPTR) consists of a high byte (DPH) and a low byte (DPL). Its

intended function is to hold a 16-bit address. It may be manipulated as a 16-bit register or as two

independent 8-bit registers.

6.6 TIMERS AND COUNTERS

Timer 0 and Timer 1:

The “Timer” or “Counter” function is selected by control bits C/T in the Special Function

Register TMOD. These two Timer/Counters have four operating modes, which are selected by



bit-pairs (M1, M0). In TMOD Modes 0, 1, and 2 are the same for both Timers/Counters. Mode 3

is different. The four operating modes are described in the following text:

Mode 0:Timer, which is an 8-bit Counter with a divide-by-32 pre scalar. The Mode 0 operation as

it applies to Timer 1. In this mode, the Timer register is configured as a 13-bit register. As the

count rolls over from all 1s to all 0s, it sets the Timer interrupt flag TF1. The counted input is

enabled to the Timer when TR1 = 1 and either GATE = 0 or INT1 = 1. (Setting GATE = 1

allows the Timer to be controlled by Putting either Timer into Mode 0 makes it look like an 8048

external input INT1, to facilitate pulse width measurements). TR1 is a control bit in the Special

Function Register TCON (Figure 3).

GATE is in TMOD: The 13-bit register consists of all 8 bits of TH1 and the lower 5 bits

of TL1. The upper 3 bits of TL1 are indeterminate and should be ignored. Setting the run flag

(TR1) does not clear the registers. Mode 0 operation is the same for the Timer 0 as for Timer 1.

Substitute TR0, TF0, and INT0 for the corresponding Timer 1 signals in Figure 2. There are two

different GATE bits, one for Timer 1 (TMOD.7) and one for Timer 0 (TMOD.3).

Mode 1:

Mode 1 is the same as Mode 0, except that the Timer register is being run with all 16

bits.

Mode 2:

Mode 2 configures the Timer register as an 8-bit Counter (TL1) with automatic reload,

as shown in Figure 4. Overflow from TL1 not only sets TF1, but also reloads TL1 with the

contents of TH1, which is preset by software. The reload leaves TH1 unchanged. Mode 2

operations are the same for Timer/Counter 0.



Mode 3:

Timer 1 in Mode 3 simply holds its count. The effect is the same as setting TR1 = 0.

Timer 0 in Mode 3 establishes TL0 and TH0 as two separate counters. The logic for Mode 3 on

Timer 0 is shown in Figure 5. TL0 uses the Timer 0 control bits: C/T, GATE, TR0, and TF0, as

well as the INT0 pin. TH0 is locked into a timer function (counting machine cycles) and takes

over the use of TR1 and TF1 from Timer 1. Thus, TH0 now controls the “Timer 1” interrupt.

Mode 3 is provided for applications requiring an extra 8-bit timer on the counter. With Timer 0

in Mode 3, an 80C51 can look like it has three Timer/Counters. When Timer 0 is in Mode 3,

Timer 1 can be turned on and off by switching it out of and into its own Mode 3, or can still be

used by the serial port as a baud rate generator, or in fact, in any application not requiring an

interrupt.

TCON and TMOD are the two registers used for setting the above modes. The format of

these registers is as shown in figure TMOD is dedicated solely to the timers and can be

considered to be two duplicate 4-bit registers, each of which controls the action of one of the

timers. TCON has control bits and flags for the timers in the upper nibble, and control bits and

flags for the external interrupts in the lower nibble.

6.7 INTERRUPTS:

Interrupts are hardware signals that are used to determine conditions that exist in external

and internal circuits. Any interrupt can cause the 8051 to perform a hardware call to an interrupt

–handling subroutine that is located at a predetermined absolute address in the program memory.

Five interrupts are provided in the 8051. Three of these are generated automatically by the

internal operations: Timer flag 0, Timer Flag 1, and the serial port interrupt (RI or TI) Two



interrupts are triggered by external signals provided by the circuitry that is connected to the pins

INTO 0 and INTO1. The interrupts maybe enable or disabled, given priority or otherwise

controlled by altering the bits in the Interrupt Enabled (IE) register, Interrupt Priority (IP)

register, and the Timer Control (TCON) register. . These interrupts are mask able i.e. they can be

disabled. Reset is a non maskable interrupt which has the highest priority. It is generated when a

high is applied to the reset pin. Upon reset, the registers are loaded with the default values.

Interrupts

Interrupt Address

RESET 0000

IE0 (External interrupt 0) 0003

TF0 (Timer 0 interrupt) 000B

IE1 (External interrupt 1) 0013

TF1 (Timer 1 interrupt) 001B

SERIAL 0023



CHAPTER –7

HARDWARE DETAILS

The IC’s and other important components used in this project work, procured from the

Hyderabad Electronics Market. The details or data sheets of the IC’s are down loaded from the

Internet. The following are the web sites that can be browsed for collecting the data sheets.

1. www. Texas Instruments.com

2. www. National semiconductors.com

3. www. Fairchild semiconductors.com

The following are the IC’s and other important components used in this project work

1. Atmel 89C2051 micro-controller

2. Atmel 89C51 micro-controller

3. L293D H – Bridge IC

4. UM3561 Gun sound simulator IC

5. 7805 Voltage Regulator

6. BC 547 NPN Transistor

The required PCB’S (Printed Circuit boards) for the project work fabricated by SUN

RISE CIRCUITS, Kushaiguda Industrial Estate, Hyderabad. Kushaiguda Industrial Estate is

very famous for fabricating the Industrial grade PCB’s



CHAPTER – 8

SOFWARE DETAILS Programming language- ASSEMBLY LANGUAGE PROGRAMMING,EMBEDDED C

Software Used-Keil µVisionSoftware Used To Dump-Proteus

8.1 PROGRAM

8.1.1 Transmitter Program

org 0000h ljmp rt

rt: MOV SCON,#40H MOV TMOD,#20H MOV TH1,#0FAH SETB TR1 CLR TI MOV P1,#0FFH MOV P3,#0FFH

main: JB P3.2,NXT2 ;Gun up

MOV A,#15HMOV SBUF,AJNB TI,$CLR TIMOV A,#65HMOV SBUF,AJNB TI,$CLR TILJMP MAIN

NXT2: JB P3.3,NXT3 ;Gun downMOV A,#20HMOV SBUF,AJNB TI,$CLR TI



MOV A,#70HMOV SBUF,AJNB TI,$CLR TILJMP MAIN

NXT3: JB P3.4,NXT4 ;Sound ONMOV A,#25HMOV SBUF,AJNB TI,$CLR TIMOV A,#75HMOV SBUF,AJNB TI,$CLR TILJMP MAIN

NXT4: JB P3.5,NXT5 ;Sound OFFMOV A,#30HMOV SBUF,AJNB TI,$CLR TIMOV A,#80HMOV SBUF,AJNB TI,$CLR TI

LJMP MAINNXT5: JB P1.2,NXT6 ;FRW

MOV A,#35HMOV SBUF,AJNB TI,$CLR TIMOV A,#85HMOV SBUF,AJNB TI,$CLR TI

LJMP MAINNXT6: JB P1.3,NXT7 ;LFT

MOV A,#40HMOV SBUF,AJNB TI,$CLR TIMOV A,#90HMOV SBUF,AJNB TI,$



CLR TI LJMP MAINNXT7: JB P1.4,NXT8 ;BCK

MOV A,#50H MOV SBUF,AJNB TI,$CLR TIMOV A,#0A0HMOV SBUF,AJNB TI,$CLR TI

LJMP MAINNXT8: JB P1.5,NXT9 ;RT

MOV A,#45HMOV SBUF,AJNB TI,$CLR TIMOV A,#95HMOV SBUF,AJNB TI,$CLR TI

NXT9: LJMP MAIN

end

8.1.2 Receiver Program

org 0000h ljmp rtrt: MOV SP,#60H

MOV P2,#00H MOV SCON,#50H MOV TMOD,#20H MOV TH1,#0FAH SETB TR1 CLR RI LCALL dddelayS

main: RCV: JNB RI,main

CLR RIDEPARTMENT OF ECE, AEC.


MOV A,SBUF NXT1: CJNE A,#15H,NXT2 JNB RI,$

CLR RIMOV A,SBUFCJNE A,#65H,main

HRZ1: SETB P2.5 CLR P2.6 ;Gun Up

LCALL DELAY CLR P2.5 CLR P2.6

LJMP MAINNXT2: CJNE A,#20H,NXT3 JNB RI,$

CLR RIMOV A,SBUFCJNE A,#70H,main

HRZ2: SETB P2.6 CLR P2.5 ;Gun Down

LCALL DELAY CLR P2.5 CLR P2.6XX: LJMP MAINNXT3: CJNE A,#25H,NXT4 JNB RI,$

CLR RIMOV A,SBUFCJNE A,#75H,XX

UD1: CLR P2.4 ;Sound ON ; LCALL DELAY

LJMP MAINNXT4: CJNE A,#30H,NXT5 JNB RI,$

CLR RIMOV A,SBUFCJNE A,#80H,XX

UD2: SETB P2.4 ;Sound OFF LCALL DELAY

LJMP MAINSTOP: MOV P2,#00HNT9: LJMP MAINNXT5: CJNE A,#35H,NXT6



JNB RI,$CLR RIMOV A,SBUFCJNE A,#85H,NT9

FRW: SETB P2.3CLR P2.2SETB P2.1CLR P2.0LCALL DELAYLCALL DELAY

CLR P2.3CLR P2.2CLR P2.1CLR P2.0LJMP MAIN

NXT6: CJNE A,#40H,NXT7 JNB RI,$

CLR RIMOV A,SBUFCJNE A,#90H,NT9

LFT: SETB P2.3CLR P2.2CLR P2.1SETB P2.0LCALL DELAYLCALL DELAY

CLR P2.3CLR P2.2CLR P2.1CLR P2.0LJMP MAIN


CLR RIMOV A,SBUFCJNE A,#95H,NXT9

RGT: CLR P2.3SETB P2.2SETB P2.1CLR P2.0LCALL DELAYLCALL DELAY

CLR P2.3



CLR P2.2CLR P2.1CLR P2.0LJMP MAIN


CLR RIMOV A,SBUFCJNE A,#0A0H,NXT9

BCK: CLR P2.3SETB P2.2CLR P2.1SETB P2.0LCALL DELAYLCALL DELAY

CLR P2.3CLR P2.2CLR P2.1CLR P2.0

NXT9: LJMP MAIN

DELAY:MOV R4,#0FFHLOOP: MOV R5,#0FFH DJNZ R5,$ DJNZ R4,LOOP RET

dddelayS: MOV R4,#60 Zz21S: MOV R5,#60 Zz11S: MOV R6,#60 DJNZ R6,$ DJNZ R5,Zz11S DJNZ R4,Zz21S RETend



CHAPTER – 9

CONCLUSION AND REFERENCES

9.1 CONCLUSION:

The project work “Wireless Warfare Vehicle” is designed and developed successfully.

For the demonstration purpose, a prototype module is constructed; and the results are found to be

satisfactory. Since it is a prototype module, a simple vehicle is constructed, which can be used

for many applications. In this concept the warfare vehicle is controlled by a remote that will be

operated by the operator. The security personals can monitor the zone and the triggering of the

gun can be done through the remote by which the gun sound simulator IC produces the gun shot

sensation.

The employment of unmanned platforms in the battlefield serves not only to overcome

the constraints arising from manpower and resource shortages, but also increases the operational

capability of a fighting force. They will provide tangible increases in combat range, firepower,

speed, element of surprise, command and control, etc. As unmanned warfare and the mastery of

unmanned technology will become increasingly important parts of a nation's strategic

architecture, here armed forces and defence industries will need to pay appropriate attention to

this aspect of warfare.



9.2 REFERENCES:

The following are the references made during design, development and fabrication of the

project work.

1. Industrial Robotics – Technology, Programming, & Applications. By: MIKELL P.

GROOVER, MITCHELL WEISS, ROGER

2. Electronic Circuit guide book – Sensors – By JOSEPH J.CARR

3. Linear Integrated Circuits – By: D. Roy Choudhury, Shail Jain

4. The concepts and Features of Micro-controllers - By: Raj Kamal

5. The 8051 Micro-controller Architecture, programming & Applications - By: Kenneth J.

Ayala

6. Programming and Customizing the 8051 Micro-controller - By: Myke Predko

7. Robotic Engineering an Integrated Approach By: Richard D. Klafter, Thomas A.

Chmiclewski, Michael Negin

8. Mechatronics – Electronic Control Systems in Mechanical and Electrical Engineering – By:

W. Bolton

9. Introduction to Robotics - By: Saeed B. Niku

10. Mobile and Personal Communication System and Services

By: RAJPANDYA


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