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
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