1.1.      Introduction

Sensor Based Automatic Gun targeting System for Border Area is an

automated gun target and firing system if found an object within a range of

sensors. The project is primarily based on PIR Sensors, Microcontroller and

wireless transmitter and receiving units using FSK.

 

The Project is required because till today, border is protected by Iron Spike

wires, and a watch tower containing a person continuously flashing the light

over the border area day and night. Those persons are fully responsible for

any intrusion.

 

This project will not fully remove the responsibility from their soldiers, but

shares the maximum responsibility and will reduce human mistakes on the

border. The sensors will sense any living object inside the range, provide the

s/g to microcontroller, in response, microcontroller generates the code on the

site and send to the watch tower where the receiver receives the code,

provides code to microcontroller, interprets the location of the object

corresponding to received code, activates targeting system, buzzer system

and at last firing system.

 

 

1.2. Objective.

The basic purpose of the project is to enhance the border security

electronically with automation and with that to reduce the work load and

responsibility of the border men that continuously take a look on border 24x7.

Currently project is capable to detect any IR radiation in the range of border,

automatically target its position and destroy the object through firing control

module.

Also, the use of project on small scale can be used in home security at night

by simply adjusting the range of the project.

 

 

1.3 Requirements

 

One of the basic requirements for the project is Accuracy. The targeting

system should be accurate enough to target and fire the target correctly. For

that we require to maintain the high resolution of the area under surveillance.

For maintaining high resolution, we should differentiate the area in very small

sub-areas and a lot a code to those areas i.e. on code corresponding to each

sub-area.

Greater the number of sub-areas more will be the bits required per code

allotted to that sub-area so increasing the complexity of coding the complete

system. The benefit is that, more resolution, more accuracy. The gun will be

targeted over the correct position and fire the target, but will not miss the

target

 

 

Hence, cost of hardware, programming and designing the area to which surveillance is to set, are the

major three requirements of the system.

 

 

Block diagrams  

 

2.1 Transmitter Section

 

 

 

2.1.1 Working of Transmitter section

The top portion of the block diagram consist of the Passive IR Sensor that detects the invisible IR radiations of the any living object and generates a weak (small) signal which goes to the OPAMP for amplification. The OPAMP hereby, amplify the signal, makes it readable to the microcontroller and then microcontroller generates a code corresponding to the sensor detection.

 

 

As the code is generated which looks like something as 0000 0000 0001,

0000 0000 0011, etc is transmitted to the encoder. The code is transmitted to

the encoder at every 1ms to the FSK Transceiver section for modulation of

signal and transmission of signal wirelessly.

 

Each passive IR sensor senses and generates the signal at different port of

the microcontroller and it then depends on the microcontroller to generate a

unique corresponding code related to the passive IR sensor detection.

Multiple passive IR sensors can detect a single object and generate codes

which in result generates signal on the multiple ports of the microcontroller.

Under such situation, it depends on the microcontroller to take the input of

multiple sensors at a time and then decide the correct location of the object on

the basis of received data.

 

 

2.2 Receiving Section

2.2.1 Working of Receiver section

The receiver contains FSK transceiver, Microcontroller, DC motor, Firing Laser gun, H- bridge function, Buzzer Alarm and the decoder IC. The signal transmitted via transmitter is received by the FSK receiver, demodulated by a demodulator and then the signal is decoded by a decoder IC. Then the s/g is transmitted to the microcontroller and microcontroller retains the code transmitted by a transmitter and performs the function accordingly.

The signal received and code regenerates is called obtained code. The format of the obtained code is the 11110001, 11110101, 11110011 etc. Each code regenerated is destined to perform some target function. It depends on the code, how much degree will the motor rotate and targets itself to the object location and then, as the targeting function is completed, the buzzer module activates and buzzer alarm system activates that alarm everyone present into the watch tower.

 

As the buzzer system gets activated, after very small delay, the firing control system gets activated, and laser gun starts firing over the destined location. The fire lasts until the sensor stops sensing the IR radiations. It is a complete destruction program of the discovered living object near the border area range.

The rotation can vary accordingly to the sensation of the sensors as the code transmitted will rapidly changes. The transmitter and receiver can be at 200m from each other. If more distant, receiver will create problem in the reception of code which is an extremely important part of the program.

The transmitter and receiver works on 443 MHz frequency.

Circuit Diagrams

 

3.1 Transmitter Section

 

3.1.1 Description of Transmitting Module Circuit Diagram

 

Describing this section includes some sub-sections as the module is divided

in sub-sections. Particularly there are 4 sections in this transmitter module as

discussed.

 

3.1.1.1 Sensor Module

 

The module is the primary module of the project. This module includes the

passive IR sensors foe sensing any living object in its range defined. Under

this, 4 sensors are planted over the border to sense any motion near the

border and alert the watch tower for the motion. The diagrammatic structue is

explained as:

 

 Here the broader view of the sensor module is provided. The passive

IR sensors are labeled as S1, S2, S3 and S4. In this, initially each sensor has

the O/P of 1 so when no sensor will sense, the combined o/p reaching at the

microcontroller is 1111. As soon as any sensor detects the object, its O/P

becomes 0 and microcontroller generates a code corresponding to the O/p of

the sensor. Now how the sensors generate signal 5v or 0v, for that a sensor

model is discussed in brief.

 

Here above, the magnified version of the sensor is shown. In this

LM358 is an OPAMP IC used to amplify the small signal generated by the

sensor S4 on detection of the object. The amplified s/g is applied to the

transistor BC548 and the transistor conducts. So O/P is connected to the

ground and so O/P becomes 0.

Here we have used the resistors R(f) of 20K and R(i) of 1K.

 V(o/p)/Vin = 1 + R(f)/R(i)

3.1.1.2 Microcontroller Code Generation 

 

Here, microcontroller will receive the s/g generated by sensors on port

P1.0, P1.1, P1.2, P1.3 and ports P1.4 – P1.7 will always remain on high

status. So the code generated is 11110001, 11110011 etc. Taking the signals

from the sensors, microcontroller generates the code corresponding to the

sensor O/P on the port P2.0, P2.1, P2.2, P2.3. The code generated can be

1000, 1100, 1110 etc. Once generated, this code is transmitted over to the

encoder, encoder encodes it and transmits it to the FSK Transceiver and FSK

transceiver transmits the code to the receiver in the watch tower.

 

3.2 Receiver Section

 

3.2.1 Description of Receiving Module Circuit Diagram  

Receiving Module consists of the Firing Control, Decoder, buzzer

Alarm System, DC Motor Targeting system, Microcontroller, relay and FSK

Transceiver. Under receiving module, there are various sections named

above are explained as:

 

3.2.1.1 Microcontroller Generating Obtained Code

As the Microcontroller receives the decoded version of the transmitted

code, it generates the 8bit code known as Obtained Code. It’s according to

the obtained code, the rotation angle of the motor is decided in the targeted

system and firing and buzzer alarm controllers will get turn on. The figures are

shown below:

Here in the above Figure, code transmitted by Transmitter is received

by the microcontroller on the ports P1.0, P1.1, P1.2, and P1.3. As explain

before, Ports 1,4- ports 1.7 are always 1, so obtained code is 11110001,

11110011 same as sent by the microcontroller on the transmitting side.

The Logic behind each unique code is programmed before and the

actions are pre-decided accordingly to the code received. Hence, when the

code is receiver, it determines the angle by which the motor has to rotate

which is a part of the Targeting System. Also the delay between firing and

buzzer alarm is also decided according to the code.

 

3.2.1.2 Mechanism behind the DC Motor Targeting System

The angle rotation of the DC Motor depends on the code received on

the microcontroller. The mechanism is the simple H-Bridge design of the DC

Motor as shown:

Here, the port 3.0 of t he microcontroller is connected to the Pin 1 of

the IC. This pin is the enable pin, so port 3.0 of microcontroller will always

remain in the +5v status.

Pin 3.1 of the microcontroller is connected to the Pin 2 of the IC and pin

3.2 is connected to the Pin 7 of the IC. The DC motor is connected to the pin

3 and pin 6 as shown.

Now the motor will follow the table below accordingly to the code

received on the microcontroller:

 

The above table shows the direction of the motor in which it will run.

The motor can run clock wise, anti clock wise or free runs. The H-bridge

structure for motor is shown as:

Now as per the figure, and the table, the motor will rotate clock wise

when s1 and s4 are connected as motor will be on 12V, but when, all S1, S2,

S3 and S4 are 0, no voltage is applied on the motor, hence motor will be

running freely.

When S2 and S3 will be on, again motor will get the 12V supply but

now, it will be reversed than before and hence, the motor will rotate anti-

clockwise.

The basic and the main role here is of delay, it means for how much

time the motor will rotate to attain the particular degree of rotation. Such thing

we will attain with the following procedure:

1.)    Discover the RPM (Rotations per minute) of the motor. This is the value of

how much rotations motor take in 60 seconds.

2.)    Discovering RPM, let 100rpm, motor will take 36000 degree rotation in 60

sec.

3.)    Now, if we want the motor to rotate 10 degree to find certain target, .0166 sec

or 16.66 ms . Now, we will provide a delay of 16 ms for a motor to rotate so

that we can attain the rotation of 10 degree.

            This was the basic operation of Targeting System to attain the

target. Now, how to attain such operation using Microcontroller. For that

referring Fig: 3.5. In this figure, Ports P3.0, P3.1 and P3.2 are connected to

the Motor driving IC L293D directly. As shown in Fig 3.6, P3.0 will always be 1

to enable the L293D IC. Then if it is required to move motor clockwise. We will

put P3.1 as 1 and P 3.2 as 0 which will make motor rotate clock-wise and

reverse action must be taken for anticlockwise rotation.

 

3.2.1.3 Buzzer Alarm System

            The basic purpose of the buzzer alarm system is to alert the

watch tower before firing the detected object. As there is manual operation

provided in the project, hence if required, the firing can be halt and automation

of the project can be manually controlled. Under the usage of project in small

scale such as in home security purposes, the basic operation of the buzzer is

to alert for the intrusion of an unwanted IR radiating obstacle.

Now for understanding the basic circuitry and working of the buzzer,

have a look on the zoomed version of the Buzzer Alarm module.

As we can see in this fig. , Pin 2.1 of a microcontroller is directly

connected to the transistor of the Buzzer Alarm module. Here, when the

object is detected and targeted, then the next step is to alert others using the

Buzzer Alarm.

Normally, the base of the transistor is Low, so it will not conduct but as

the microcontroller will provide P2.1 in high state, the base of the transistor

will become high and then, transistor will begin to conduct. Now first we will

discuss the operation when P2.1 is 0 because no object is detected, then we

will discuss what will be the scenario when the object will be detected.

Ø When no object is detected by sensors, P2.1 will remain on 0. Transistor will

be on the Low state. There will be 5V supply on both sides of the buzzer as

transistor is off. So buzzer will be quiet.

Ø As the object is detected, the Pin 2.1 of the microcontroller will become high

after the object is targeted. As the Pin will provide 1, the base of the transistor

will become high and the transistor will start to conduct. Then the voltage

across the buzzer system will become 12V.

Ø As soon as the 12V is formed across the Buzzer Alarm system, the Buzzer will

start to blow.

This is how the buzzer alarm system will continue to work as soon as

the object is detected by the sensors on the transmitter section.

 

3.2.1.4 Firing Control System

            The firing control system controls bullet fire unless the sensor

detects any motion within the specified border range. To completely

understand the system of the system of firing control, we should refer the

figure below.

            Taking a look on the Fig: 3.9, we can see that microcontroller

Port 2.0 is connected to the firing control module. Here, the trigger of the gun

is replaced by the relay switch for automation in firing.

            As seen, from above there can be 2 cases i.e. when the Port P

2.0 is 0 and other when the Port P 2.0 is high. Below the both cases are

discussed thoroughly.

Ø When the port 2.0 of the microcontroller is 0, then the transistor connected to it,

its base will be low and hence the transistor will not conduct. When this

happens, the voltage around the magnetic coil will be 0V hence there will be

no magnetism left. So the relay will not be connected and the gun will not fire.

Ø When the port 2.0 will be high on the object detection by the sensors, the

transistor base will become high and the transistor will conduct. When this

occurs the voltage of 12V will be developed across the magnetic coil, and the

coil will be magnetized. Due to this, the iron strip will be attracted and joined

to the lower portion of the conducting part in relay and hence the switch will

get on.

Ø As soon as the switch will get on, the firing starts unless the object is

completely destroyed or the sensor stops sensing IR radiation.

 

This was the working of the Transmitter and Receiver module and the functioning of the CKT Diagram and the step by step procedure of the working of the project