Submitted in partial fulfillment of the requirements of
Professional Degree of Bachelor of Technology in
Electronics and Communication Engineering
Of the University of Kerala



The report in doc format can be accessed from here:
http://sharingmatrixfile/13958657/MINI_PROJECT_REPORT2.docx

CONTENTS

INTRODUCTION
BLOCK DIAGRAM
BLOCK DIAGRAM DESCRIPTION
CIRCUIT DIAGRAM
CIRCUIT DIAGRAM DESCRIPTION
WORKING OF THE CIRCUIT
PROGRAMMING
PCB LAYOUT
FABRICATION OF PCB
ASSEMBLY & TESTING
DATASHEET

INTRODUCTION

The threat of buried unexploded mines & bombs continues to be a danger for communities today. Many regions of the world have many miles of un-cleared mines that are still active and their detonation causes severe injury or death. The buried bombs are a threat to both vehicles and personnel and thus prohibit the safe travel of both the military and civilians.
Buried mines and unexploded bombs are generally found in conflict zones, however, the random nature of their distribution means that they can pose a threat for decades after the cessation of hostilities if they aren't properly identified and disposed of.
Our project is mainly indent to eliminate or reduce such dangers. By using this robot we can detect the presence of mines. If in case any problem occurs during detection, like explosion of mines & bombs it will cause only the damage of robot, instead of causing the death of civilians or militants. Damage of robot is not a big matter due the low cost. And we can make a new one in within no time.

BLOCK DIAGRAM DESCRIPTION
1. MAIN BLOCK DIAGRAM

The main block diagram covers the Remote Control part and the Robotic part. The remote control part includes keypad, encoder, and transmitter module. The robotic part includes decoder, receiver module, microcontroller and motor driver. The description of each blocks are given below:
KEYPAD
This unit consists of four switches which are used for controlling the robot.
ENCODER
The encoder IC used in the circuit is HT12E. It converts the parallel data, which is inputted with the help of switches, into serial data. It is an active low IC.
TRANSMITTER MODULE
This module transmits the data from the encoder at a frequency of 434MHz. Efficient transmission can take place within a range of 60 meters with the help of an antenna. Amplitude Shift keying modulation is used for transmission of data.

RECEIVER MODULE
The receiver module consists of two sections; reception and demodulation. The reception module receives the data transmitted from the transmitter module. The other unit demodulates the received data and separates the wanted data, which is then sent to the decoder.
DECODER
The decoder IC used is HT12D. It converts the serial data, from the receiver, into parallel data. It is an active low IC.
MICROCONTROLLER
The microcontroller IC used is PIC16F877A. PIC is the abbreviation of ËœProgrammable Interface Controlâ„¢. It is a programmable and reprogrammable IC. By using software like MPLAB, micro C etc; the IC can be programmed to control the motor driver, based on the decoder output.
MOTOR DRIVER
The motor driver IC used is L293D. It controls the motor, and thereby the motor wheels which makes the robot to move.


2. MINE DETECTOR BLOCK DIAGRAM
The mine detector part which is placed inside the robot consists of two oscillators, mixer, amplifier, filter and buzzer. The description of each blocks are given below:
REFERENCE COIL OSCILLATOR
The oscillator used is colpitts oscillator, which is designed to a particular frequency called the reference frequency, by adjusting the coil windings.
SEARCH COIL OSCILLATOR
The oscillator used here is also colpitts oscillator, which has the same frequency as the reference oscillator. Unlike reference oscillator, the coil of the search oscillator is placed outside the robotic part, which acts as the search coil that changes the frequency from the initial when a metal is present at its surrounding.
MIXER
The mixer circuit compares the two frequencies from the reference oscillator and search oscillator, and produces a frequency which is the sum and difference of two.


FILTER
The filter circuit produces an output with frequency, which is the difference frequency from the mixer output. All other frequencies from the mixer are filtered off.
AMPLIFIER SECTION
The amplifier amplifies the filtered output from the filter. The amplifier is an audio frequency amplifier.
BUZZER
It produces a beep sound, when robot detects mine.

CIRCUIT DESCRIPTION

The circuit can be divided into three sections:

1. Remote section
2. Receiver section
3. Mine Detector section

1. REMOTE SECTION

Remote section consists of mainly two parts:
ENCODER IC

The 2^12encoders are a series of CMOS LSIs for remote control system applications. They are capable of encoding information which consists of N address bits and 12-N data bits. Each address/data input can be set to one of the two logic states. The programmed addresses/data are transmitted together with the header bits via an RF or an infrared transmission medium upon receipt of a trigger signal. The capability to select an inverted TE trigger on the HT12E or a DATA trigger on the HT12A further enhances the application flexibility of the 2^12 series of encoders. The HT12A additionally provides a 38 kHz carrier for infrared systems.

TRANSMITTER MODULE

The TWS-434 and RWS-434 are extremely small, and are excellent for application requiring short-range RF remote controls. The transmitter module is only 1/3 the size of a standard postage stamp, and can easily be placed inside a small plastic enclosure.

TWS-434:
The transmitter output is up to 8mW at 433.92MHz with a range of approximately 400 foot (open area) outdoors. Indoors, the range is approximately 200 foot, and will go through most walls. Transmitter accepts both linear and digital inputs can operate from 1.5 to 12 Volts-DC, and makes building a miniature hand-held RF transmitter very easy. The TWS-434 is approximately the size of a standard postage stamp

2. RECEIVER SECTION
The different sections of the receiver section are explained below:
RECEIVER MODULE

RWS-434:
The receiver also operates at 433.92MHz, and has a sensitivity of 3uV.The RWS-434 receiver operates from 4.5 to 5.5 volts-DC, and has both linear and digital outputs.

DECODER

The 2^12 series of decoders provides various combinations of addresses and data pins in different packages so as to pair with the 2^12 series of encoders. The decoders receive data that are transmitted by an encoder and interpret the first N bits of code period as addresses and the last 12-N bits as data, where N is the address code number. A signal on the DIN pin activates the oscillator which in turn decodes the incoming address and data. The decoders will then check the received address three times continuously. If the received address codes all match the contents of the decoder's local address, the 12-N bits of data are decoded to activate the output pins and the VT pin is set high to indicate valid transmission. This will last unless the address code is incorrect or no signal is received. The output of the VT pin is high only when the transmission is valid. Otherwise it is always low. Output type Of the 2^12 series of decoders, the HT12D has no data output pin but its VT pin can be used as a momentary data output.

MICROCONTROLLER

The microcontroller used here is PIC16F877A. The PIC16F877A is a CMOS FLASH-based 8-bit microcontroller. It is a 40 pin DIP with an operating speed of 20MHz and 20ns instruction cycles. The operating voltage is 4.0 to 5.5 volts. The PIC16F877A features 256 bytes of EEPROM data memory, self programming, an ICD, 2 Comparators, 8 channels of 10-bit Analog-to-Digital (A/D) converter, 2 capture/compare/PWM functions, the synchronous serial port can be configured as either 3-wire Serial Peripheral Interface (SPI) or the 2-wire Inter-Integrated Circuit (I²C) bus and a Universal Asynchronous Receiver Transmitter (USART). The PIC16F877A microcontroller is programmable and reprogrammable using software™s like MPLAB, micro C etc.

MOTOR DRIVER

The motor driver used here is L293D. The L293D is a quadruple push-pull 4 channel driver capable of delivering 600 mA (1.2 A peak surge) per channel. The L293D is ideal for controlling the forward/reverse/brake motions of small DC motors controlled by a microcontroller such as a PIC or BASIC Stamp.

The L293D is a high voltage, high current four channel driver designed to accept standard TTL logic levels and drive inductive loads (such as relays solenoids, DC and stepping motors) and switching power transistors. The L293D is suitable for use in switching applications at frequencies up to 5 KHz.

3. MINE DETECTOR SECTION


The mine detector section consists of two oscillators, a mixer, a filter, an amplifier and a buzzer. The oscillators used are colpitts oscillator. The part consisting of transistor (2N2222) Q1, resistors R1 &R2, capacitors C1 & C2, and inductor coil L1, in the circuit diagram, is the reference oscillator. The part consisting of transistor Q2, resistor R3 & R4, capacitor C3 & C4, and inductor coil L2, in the circuit diagram, is the search coil oscillator. The mixer part consists of transistor Q3, resistor R5, and capacitor C5. The rest of the circuit excluding capacitor C6 & C7 is the amplifier part. The LS1 is the buzzer.
The resistors used here are of value 10k, and 39k. These are general purpose carbon film resistors with a

5% tolerance and rated at 1/4 watt. You could use resistors of a higher wattage as this does not affect the working they just get bigger. 1 watt or bigger will not fit on the board.
The capacitors used here are of value 10nF, 100nF, and 220uF. The 10nF and 100nF capacitors are ceramic type or disk type capacitors. The 220uF capacitor is polyester type.
The transistor used is 2N2222 NPN transistor. Any transistor of NPN type, like 2N3904, BC107, BC547 etc can be used.

WORKING OF THE CIRCUIT

The Wireless Controlled Mine Detecting Robot has three main parts, namely remote control part, receiver part, and mine detecting part. The mine detecting part is placed inside the robot.
The robot is manually controlled by a wireless remote control. The wireless remote control consists of four push button switches, an encoder, a transmitter module and an antenna. The four Push Button switches are used to control the movement of the robot. In the encoder, there is a total of 12 address pins. The last four pins (A8-A11) act as the data input pins. The pins A0-A7 have been set as default at logic0.When a switch is pressed, the corresponding binary input to that data input pin of the encoder, which initially is at logic 1, goes to logic 0 while the remaining 3 pins are at logic 1.Depending on this input, the encoder generates a serial output and gives it to the data input pin of the transmitter module. The transmitter module modulates this signal (ASK Modulation) and transmits it at a frequency of 434MHz through an antenna.
The receiver part consists of a receiver module, a decoder, a micro controller, two motor drivers and motor wheels. The receiver module receives the transmitted data. The data is then demodulated and sent to the decoder. Now the decoder checks the matching of the default address set at the encoder. Only if the addresses match will the serial data be converted into parallel data. After the conversion the parallel data is given to the microcontroller, which is programmed using micro C. The microcontroller is so programmed that upon receiving the parallel input data, it activates or gives power to the motor driver to manage the motor 
wheels. Thus the motor wheels moves forward, backward, left and right, according to the users wish, who control the wireless remote control.
The mine detecting part, which is the important part, consists of a reference oscillator, a search oscillator, a mixer, a filter, an amplifier and a buzzer. The mine detecting part or the mine detector is placed inside the robot. The two oscillators here produce a radio frequency. The search oscillator uses a coil of wire that is placed outside the robot. The other oscillator uses a much smaller coil of wire, and is usually placed inside the robot. Initially the oscillators are adjusted so as to make their frequencies very nearly the same. The difference between them is made audible as a beat note. This beat note changes slightly when the search oscillator coil, which is placed outside the robot, move over or near to a piece of metal. The mixer circuit gives sum and difference frequency of the two oscillator frequencies. The filter circuit passes the difference frequency and blocks all other frequency. This filtered output is passed on to an amplifier which amplifies the input signal to the amplifier and gives to the buzzer. Thus an audible sound is produced from the buzzer, indicating the detection of metal.

PROGRAMMING

ASSEMBLY AND TESTING


Assembly consists of soldering of components and wires on to the PCB and mechanical fitting of wired PCB and other assemblies. Testing is carried out even at design phase itself in breadboard level to verify the design, so that little or no circuit changes are required after designing the PCB.

¢ Soldering

Before soldering, all the discrete components are tested. The leads of the components are cleaned with a fine abrasive paper. The PCB also thoroughly cleaned by scratching the areas to be soldered. The leads of the components are bend properly, inserted into the holes and placed correctly. A small quantity of flux is applied to the component leads and pads to remove the oxide coating. The leads are soldered with good quality solder with sufficient heat from the soldering iron. Excess heat will result in improper soldering and may damage the component. All the joints are checked after the soldering.

¢ Testing

After soldering the components on to the PCB, the board is thoroughly cleaned for any residual flux and wire leads. All the components are checked for their value and for the proper orientation if applicable. Before ICs are inserted into the sockets, power 
applied to the board and voltages are measured at the IC power point. Power is switched off before the ICs are inserted. Press the required switch and check whether the corresponding code is available at various stages.

¢ Assembly

The tested PCB is placed inside a robotic part in a compact manner. The PCBs are arranged in layers inside the robotic part. The remote control section PCB is placed in a plastic box, with switches projected on the top of the box. The antenna is also projected outwards the box.
[attachment=4002]

[attachment=6769]

remotely control a device or remotly controlled robort



INTRODUCTION

Radio control (often abbreviated to R/C or simply RC) is the use of radio signals to remotely control a device. The term is used frequently to refer to the control of model vehicles from a hand-held radio transmitter. Industrial, military, and scientific research organizations make [traffic] use of radio-controlled vehicles as well.
A remote control vehicle is defined as any mobile device that is controlled by a means that does not restrict its motion with an origin external to the device. This is often a radio control device, cable between control and vehicle, or an infrared controller. A remote control vehicle (Also called as RCV) differs from a robot in that the RCV is always controlled by a human and takes no positive action autonomously.
One of the key technologies which underpin this field is that of remote vehicle control. It is vital that a vehicle should be capable of proceeding accurately to a target area; maneuvering within that area to fulfill its mission and returning equally accurately and safely to base.


STATEMENT OF THE PROBLEM

The objective of our project, is to control the robot by a mobile phone (as transmitter) that makes call to the mobile phone (as receiver) attached to the robot. Now after answering the call, and in the course of the call, if any button is pressed control corresponding to the button pressed is heard at the other end of the call. This tone is called dual tone multi frequency tome (DTMF) robot receives this DTMF tone with the help of phone stacked in the robot.
The received tone is processed by the 16F72 microcontroller with the help of DTMF decoder MT8870 the decoder decodes the DTMF tone in to its equivalent binary digit and this binary number is send to the microcontroller, the microcontroller is preprogrammed to take a decision for any give input and outputs its decision to motor drivers in order to drive the motors for forward or backward motion or a turn. The mobile that makes a call to the mobile phone stacked in the robot acts as a remote. So this simple robotic project does not require the construction of receiver and transmitter units. DTMF signaling is used for telephone signaling over the line in the voice frequency band to the call switching center. The version of DTMF used for telephone dialing is known as touch tone. DTMF assigns a specific frequency (consisting of two separate tones) to each key s that it can easily be identified by the electronic circuit. The signal generated by the DTMF encoder is the direct al-gebric submission, in real time of the amplitudes of two sine (cosine) waves of different frequencies, i.e., pressing 5 will send a tone made by adding 1336 Hz and 770 Hz to the other end of the mobile.

BACKGROUND OF THE PROBLEM

The First Remote Control Vehicle / Precision Guided Weapon :
This propeller-driven radio controlled boat, built by Nikola Tesla in 1898, is the original prototype of all modern-day uninhabited aerial vehicles and precision guided weapons. In fact, all remotely operated vehicles in air, land or sea. Powered by lead-acid batteries and an electric drive motor, the vessel was designed to be manoeuvred alongside a target using instructions received from a wireless remote control transmitter. Once in position, a command would be sent to detonate an explosive charge contained within the boat's forward compartment.

The weapon's guidance system incorporated a secure communications page link between the pilot's controller and the surface-running torpedo in an effort to assure that control could be maintained even in the presence of electronic countermeasures. To learn more about Tesla's system for secure wireless communications and his pioneering Implementation of the electronic logic-gate circuit read ‘Nikola Tesla — Guided Weapons & Computer Technology’, Tesla Presents Series Part 3, with commentary by Leland Anderson.

Use of Remote Controlled Vehicles During World War II :
During World War II in the European Theater the U.S. Air Force experimented with three basic forms radio control guided weapons. In each case, the weapon would be directed to its target by a crew member on a control plane. The first weapon was essentially a standard bomb fitted with steering controls. The next evolution involved the fitting of a bomb to a glider airframe, one version, the GB-4 having a TV camera to assist the controller with targeting. The third class of guided weapon was the remote controlled B-17. It's known that Germany deployed a number of more advanced guided strike weapons that saw combat before either the V-1 or V-2. They were the radio-controlled Henschel's Hs 293A and Ruhrstahl's SD1400X, known as "Fritz X," both air-launched, primarily against ships at sea.


TECHNOLOGY USED- DTMF
INTRODUCTION
DTMF (dual tone multi frequency) is the signal to the phone company that you generate when you press an ordinary telephone's touch keys. In the United States and perhaps elsewhere, it's known as "Touchtone" phone (formerly a registered trademark of AT&T). DTMF has generally replaced loop disconnect ("pulse") dialing. With DTMF, each key you press on your phone generates two tones of specific frequencies. So that a voice can't imitate the tones, one tone is generated from a high-frequency group of tones and the other from a low frequency group. Here are the signals you send when you press your Touch-tone phone keys

hello sir by using RADAR we can also detect the mines....why we are using this robot?

can you explain how do you going to implement this project using RADAR ?

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