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Int. J. Mech. Eng. & Rob. Res. 2015 Bharath J, 2015

AUTOMATIC LAND MINE DETECTION ANDSWEEPER ROBOT USING MICROCONTROLLER

Bharath J1*

*Corresponding Author: Bharath J,[email protected]

The landmine crisis is globally alarming since there are presently 500 million unexploded, buriedmines in about 70 countries. Governments are looking into this situation seriously since landminesare claiming the limbs and lives of civilians every day. The purpose of this paper is to design arobot prototype which is capable of detecting buried land mines and changing their locations,while enabling the operator to control the robot wirelessly from a distance. This technologyinterfaces the metal detector circuit in a robot to search the land mines. The metal detectorcircuit is interfaced with the robot and it is left on the required search area in order to detect themetallic components used in the landmines. The main advantage in this project is that we canmake this robot at low cost and more efficient.

Keywords: Automatic Robot, Changing Place of Landmine, Landmine Detection, Microcontrollerbased Robot

INTRODUCTIONAn automatic robot, which is capable ofdetecting buried landmines and taking fromtheir locations, while enabling the operator tocontrol the robot wirelessly from a distance(Minh Dao-Johnson Tran et al., 2010). Thedetection of the buried mine is done by usingmetal detectors since most land minescontain metal components. The robot willtravel in a straight line path. The system allowsthe operator to stay at a safe distance byenabling him to control the robot wirelesslyor remotely (Kuo-Lan Su et al., 2011). The

ISSN 2278 – 0149 www.ijmerr.comVol. 4, No. 1, January 2015

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Int. J. Mech. Eng. & Rob. Res. 2015

1 Department of Electronics and Communication Engineering, Sri Venkateshwara Institute of Science and Technology, Thiruvallur.

robot travels at (2 x (radius of wheel x numberof rotations) 2.8 kilometer/hour. The robotdetects landmine using metal detector. Whenthe metal is detected, robot stops and move100 mm distance and down theelectromagnetic material and i t getsmagnetized and lift it up after attracting thelandmine (Scott, 2007).

OBJECTIVESLandmine Clearance

A land mine detection robot is needed to bedesigned to employ in peace support

Research Paper

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operations and in the clearance ofcontaminated areas.

Wireless Control

For the safety of the operator, the designedrobot must be able to operate remotely (Kuo-Lan Su et al., 2011); moreover, it is equippedwith wireless data transmitting capabilities.

Low Cost and High Reliability

The robot can be constructed in low cost ofsome hundreds of US dollars and less complexwith high reliable structure.

COMPONENTS OF ROBOTAND ITS FUNCTIONSAcrylic Sheets and Spacers

Acrylic sheet is used to construct the body ofthe robot. This material has unique physicalproperties and performance characteristics.Acrylic sheets are less in weight and highlydurable. It is also an excellent insulator, so thatthe electronics and electrical parts of the robotare safe in terms of electrical hazards.

A spacer is a type of hardware, which isused to maintain space between two sheetsin our robot. Spacer is used to maintain ourrobot stable on operation and we are using 3mm bronze spacer and 150 mm aluminumspacer in our project.

DC Motors

Here, 30 rotations per minute (RPM) CentreShaft Economy Series DC Motor are used andit is high in quality as well as low cost DCgeared motor. The motor is DC type 4-12 Voltsmotor and gives 30 rotations per minute in 12volts.

Wheels

Wheels are 109 mm Diameter x 21 mm Thickx 6 mm bore wheel is used.

Relays

By using relays we can control DC motordirection of rotation. So, by using series ofrelays we can control robot movement (Jaradatet al., 2012).

MicrocontrollerThe ATmega8 is a low power ComplementaryMetal-Oxide Semiconductor (CMOS) 8-bitmicrocontroller based on the AVR enhancedRISC architecture used to control theoperations of the robot.

Figure 1: Dimensions of Robot Prototype

GENERAL BLOCK DIAGRAMOF ROBOTIC COMPONENTS

Figure 2: Components of Transmitterand Receiver Parts of Robot and Wireless

Controller

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Encoder

The HT-12E Encoder Integrated Circuits (IC)are series of CMOS Low Scale Integration(LSI) for remote control system applicationsof the robot. They are capable of Encoding 12bit of information which consists of N addressbits and 12-N data bits.

Decoder

The HT-12D Decoder ICs are series ofCMOS LSIs for remote control systemapplications of the robot. The Decoderreceive the serial address and data from itscorresponding decoder, transmitted by acarrier using an RF transmission mediumand gives output to the output pins afterprocessing the data.

Colpitts Oscillator

Colpitts oscillator with induction coil act as ametal detector circuit in the robot’s minedetection part. By using an inductor coil, wecan detect presence of metal. When metal iskept near an inductor due to mutual inductancethere will be change in frequency of oscillation(Scott, 2007). One of the advantages of thiscircuit is its simplicity; it needs only a singleinductor. As a metal object is brought close tothe inductor, the amplitude of the voltageacross the tank circuit gradually begins to drop.Here, the feedback factor for the Colpitts istypically 0.1 to 0.5, or 10 to 50%. It has inductorconstant value of 650henry. So the frequencyof oscillation is approximately 2 kHz.

If the series combination of C1 and C2creates the effective capacitance of the(inductance is L and Capacitance is C) LCtank circuit with one inductance, then thefrequency of oscillation derived from the belowequation.

21

21

0

2

1

CC

CCL

f

Colpitts oscillator response to the signalfrom the detector coil based on mutualinductance. The signal frequency from thedetector coil varies based on the contact withmetal surface to activate the Colpitts oscillatorto send voltage to the alarm unit.

Figure 3: Metal Detector CircuitConnected with Inductive Detector

Mutual Inductance

Inductors generate an opposing voltage

Figure 4: Mutual Inductance, When theDetector Coil Placed Near the Landmine

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proportional to the rate of change in current ina circuit. This property is called self-inductance. Suppose two coils are placed neareach other, as shown in Figure 4. Changingcurrent in coil 1 produces changing magneticflux in coil. Mutual induction is current in onecoil induces electromotive force (EMF) in othercoil. Due to this property of inductance, whenmetal is kept near to the inductor it changesits value leads to change in operating frequencyof Colpitts oscillator.

Controller Unit

Controller has joystick for their specificfunctions like forward, backward, up anddownwards movement, with 2 buttons for liftingand dropping of electromagnetic material.When detection circuit detects the presenceof metal it activates alarm and using controlunit, so that activating the green butting in thecontroller, we can down electromagnet nearground and lift inside the robot using red colorbutton. We are using analog joystick, it givesanalog signal for directions and microcontrolleritself converts into digital and gives to encodersection.

Using transmitter antenna, we transmitAmplitude Shift Keying (ASK) waves toreceiver and signal can be decoded indecoder section in receiver. Joystick transmits8-bit data and encoder converts into 4-bit datato microcontroller and transmitter IC convertsparallel to serial data transfer to receiver.

RF Transmitter and Receiver

The RX-ASK is an Amplitude Shift Keying(ASK) Hybrid receiver module. It is an effectivelow cost solution for using 433 MHz’s. The TX-ASK is an ASK hybrid transmitter module. TX-ASK are designed by the saw resonator, withan effective low cost, small size and simple touse for designing. The RF 433 is ideal forremote control applications where low costand longer range is required.

The transmitter operates from a 1.5-12 Vsupply, making it ideal for battery-poweredapplications. The transmitter employs a saw-stabilized oscillator, ensuring accuratefrequency control for best range performance.

Power Supply

A regulated power supply is obtained from thebatteries attached in the robot. It provides 5-12 Volt supply of DC power.

Rectifier Circuit

A rectifier converts Alternating Current (AC),which periodically reverses direction, to DirectCurrent (DC), which flows in only one direction.The process is known as rectification. So thatrectifier is used to convert the AC from thetransmission lines to DC, which accepts by theelectronic circuits used.

ICSP Connector

In System Programming (ISP) is a technique

Figure 5: Controller Unit

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where a programmable device isprogrammed after the device is placed in acircuit board. In-Circuit Serial Programming(ICSP) is an enhanced ISP techniqueimplemented in Microchip’s PIC micro On-Time-Programmable (OTP) and flash-Reduced Instruction Set Computing (RISC)microcontrollers (MCU). Use of only two input/output pins to serially input and output datamakes ICSP easy to use and less intrusive onthe normal operation of the microcontrollers.To interface with computer system andmicrocontroller, ICSP connector is used andalso to load the program in microcontroller.

ROBOT’S OPERATIONThe robot prototype placed in the field containssome landmine like metal bodies. When thedetector contacts with the metal body, due tomutual inductance it activates the Colpittsoscillator to provide signal to the alarm unit.When the alarm signal is activated, the userhaving the controller unit press the loadingbutton, so the robot moves some distance anddown the electromagnetic material and it getsmagnetized to attract the landmine withoutdetonating it. As soon it attracts, it can bemoved towards the users place using wirelesscontroller. Then, the user pressed the unloadingbutton to drop the landmine so that user candiffuse it safely.

PROGRAMMING SECTIONThe tool used to program the microcontrolleris codewizard AVR studio.

An Example Program for Transmitter

#include <avr/io.h>

#include <util/delay.h>

#include <math.h>

#define F_CPU 16000000;

void main()

{

DDRA = 0x00;

PORTA = 0x00;

DDRD = 0xff;

PORTD = 0x00;

while(1)

{

int i;

/*Manual Mode */

if(PORTA == 0x00)

{

PORTD=0001;

}

if(PORTA == 0x02)

{

PORTD=0010;

}

if(PORTA == 0x04)

{

PORTD=0100;

}

if(PORTA == 0x08)

{

PORTD=1000;

}

}

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}

}

An Example Program for Receiver

#include <avr/io.h>

#include <util/delay.h>

#include <math.h>

#define F_CPU 16000000;

void main()

{

DDRA = 0xff;

PORTA = 0x00;

DDRD = 0x00;

PORTD = 0x00;

while(1)

{

int i;

/*Manual Mode */

if(PORTD == 0x00)

{

PORTA=00001010;

}

if(PORTD == 0x02)

{

PORTA=00001001;

}

if(PORTD== 0x04)

{

PORTA=00001100;

}

if(PORTD == 0x08)

{

PORTA=0000011;

}

}

}

}

RESULTSThe robot prototype executes successfully andit detects the landmine like metal bodies andit changes their position into safe position.Hence the robot is operated at safe distancefrom landmine fields and it sweeps landminesfrom mine fields. The test runs carried out withthe prototype assure us of the success of therobot.

• Robot is operated by a wireless RF moduleto move in four directions, i.e., forward,backward, left and right directions.

• RF Module can be operated at a distanceof 100 m.

• Metals can be detected by using simplemetal detector circuit (induction coil withColpitts oscillator).

FUTURE ENHANCEMENTSThe robot prototype detects and changed theplace of landmine model. However, in case oforiginal mine field it may have some difficultiesto deploy. So, this prototype has to improvedin the following ways to deploy in the actualmine field.

• The detection unit only able to detect metalsthat is larger than M8 nut. But replacing withlarge circumference electromagnet coil can

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be used to avoid these problems.

• Since this prototype wirelesscommunication is limited to some 100meters distance. But the wireless range canbe extended by adding highly developedwireless controllers in the robot.

• The detection coil unit is in fixed place inthis robot prototype. So implementing aservomotor connection with the detectionunit makes it to cover overall forwarddistance of the robots structure byimplementing right/left movements in thedetection coil.

• In case of plastic landmine detection, thedetector can be replaced by groundpenetrating radar or other detectionmechanism.

• Camera can be installed in the robot tosurvey the minefield and gives report to theuser or human controller.

• Wheels size should be increased to uploadthe landmine from the actual mine fields. Wecan install shock absorbers and adjustersto the wheel unit, so that it can run on anylandmine field.

CONCLUSIONIn the present investigation of the currentprototype of automatic landmine detection andsweeper robot has been presented and it canbe built using some hundreds of US dollars.So huge investments on landmine detectioncan be reduced in the countries are threatenedby landmines. This prototype provides lesscomplex structure and reduced the cost to builda landmine detection robot. It detects theuneven landmines present under the ground

and generates alarm to the user andsuccessfully changes the place of landmine bytaking safely from one place to another, withouthazard of explosion.

ACKNOWLEDGMENTI would like to convey my thanks to Mr. LakshmiNarayanan, Mr. Vinoth Kumar, Mr. Suresh, Mr.Naresh and all of my college staffs for theirsupport to complete my research work. I liketo convey my special thanks to my parents forsupporting to build this prototype andsuccessfully completing this research paper.

REFERENCES1. Jaradat M A, Bani Salim M N and Awad

F H (2012), “Autonomous NavigationRobot for Landmine DetectionAppl ications”, 8th InternationalSymposium on Mechatronics and itsApplications (ISMA), April, pp. 1-5.

2. Kuo-Lan Su, Hsu-Shan Su, Sheng-WenShiao and Jr-Hung Guo (2011), “MotionPlanning for a Landmine-Detection

Figure 6: Prototype of AutomaticLandmine Detection and Sweeper Robot

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Robot”, Artif icial Life and Robotics,Vol. 16, No. 3, pp. 277-280.

3. Minh Dao-Johnson Tran, CaniciousAbeynayake, Lakhmi C Jain and Lim CP (2010), “An Automated DecisionSystem for Landmine Detection andClassification Using Metal Detector

Signals”, Innovations in Defence SupportSystems, Vol. 304, No. 1, pp. 175-200.

4. Scott W R (2007), “BroadbandElectromagnetic Induction Sensor forDetecting Buried Landmines”,Geoscience and Remote SensingSymposium, Vol. 99, July, pp. 22-25.

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