Remote Controlled Metal Detecting Robot with
Remote Image Transmission
Submitted in partial fulfillment of the requirements for the award of the degree of
BACHELOR OF TECHNOLOGY
Electronics and Communication Engineering
Under the guidance of
Mr. S. Bhargav Kumar.
Department of Electronics & Communication Engineering
SRIDEVI WOMEN’S ENGINEERING COLLEGE
(Affiliated to Jawaharlal Nehru Technological University, Hyderabad)
V.N.PALLY, GANDIPET, R.R.DIST-500 075
(Affiliated to Jawaharlal Nehru Technological University, Hyderabad)
V.N.PALLY, GANDIPET, R.R.DIST-500 075
Department of Electronics & Communication Engineering
Certified that the project “Remote Controlled Robot with Remote Image Transmission” is the bonafide work of D.SPARSHA (07D21A0443) and G.VANDANA (07D21A0455), who carried out the project under my supervision from May to June in partial fulfillment of the requirements for the award of B.Tech Electronics &Communication Engineering to Jawaharlal Nehru Technological University, Hyderabad.
Certified further, that to the best of my knowledge the work reported here in does not form part of any dissertation on basis of which a degree was conferred on an earlier occasion on this or any other candidate.
Internal Guide Head of the Department
Mr.S.Bhargav Kumar. Dr.Y. RAJASREE
Assistant Professor Professor & HOD
Department of ECE Department of ECE
The project entitled ^ is a record of the bonafide work undertaken by us towards partial fulfillment of the award of Degree of Bachelor of Technology. The results in this project work have not been submitted to any other University or Institute for the award of any Degree or Diploma.
Path Finder was sent to Mars in 1998. This was achievement a great which detected the secrets of “Mars”. This project deals with RF controlled robot. This robot prototype for the “Path Finder”.
This robot is controlled by a RF remote. This can be moved forward and reverse direction using geared motors of 60RPM. Also this robot can take sharp turnings towards left and right directions. This project uses AT89S52 MCU as its controller. A high sensitive induction type metal detector is designed using colpitts oscillator principle and fixed to this robot. Also a wireless camera with voice is interfaced to the kit.
When the robot is moving on a surface, the system produces a beep sound when metal is detected. This beep sound will be transmitted to remote place. Simultaneously the images around the robot will be transmitted to remote place. User can monitor the images and metal detection alarms on Television.
The RF modules used here are STT-433 MHz Transmitter, STR-433 MHz Receiver, HT640 RF Encoder an HT648 RF Decoder. he three switches are interfaced to the RF transmitter through RF Encoder. The encoder continuously reads the status of the switches, passes the data to the RF transmitter and the transmitter transmits the data.
This project uses 9V battery. This project is much useful for mines detection and surveillance applications
First and foremost, our sincere thanks to ^ , Principal and Head of the department of Electronics and Communication Engineering, Sridevi Women’s Engineering College, V.N.Pally, Hyderabad for providing this opportunity to carry out the present project work and for her encouragement and advice during the course of this work.
We indebted to our internal project guide ^ , Assistant Professor of Electronics and Communication Engineering, for his excellent guidance, constant inspiration and encouragement in the completion of this dissertation.
We would like to express our thanks to all the Faculty members, Staff of Department of Electronics & Communication Engineering, who have rendered valuable help in making this project a successful one.
Table No Name of the Table Page No
3.1. Pin Description of HT640L Encoder 10
3.2 Pin Description of HT648L Decoder 12
4.1. Alternate Functions of port 3 15
5.1. Operation of H-Bridge 17
Figure No Name of the Figure Page No
3.1 Regulated Power Supply 5
3.2 Full Wave Bridge Rectifier 6
3.3 Circuit Diagram and respective output
Waveforms of Capacitive Filter 6
3.4 RF Transmitter STT-433MHz 7
3.5 Transmitter circuit 7
3.6 HT640 Encoder 9
3.7 RF Receiver STR-433MHz 10
3.8 Pin Diagram of RF Receiver STR-433MHz 11
3.9 HT648L Decoder 12
4.1 Block Diagram of AT89C51 14
4.2 Pin Diagram of AT89C51 15
5.1 Graphical Representation of H-Bridge 16
6.1 Metal Detecting circuit 18
7.1 Block Diagram of RF Transmitter (Remote) 20
7.2 Block Diagram of RF Receiver (Remote) 21
10.1 RF Receiver Section (Robot) 28
10.2 RF Transmitter Section (Remote) 28
1 PROJECT OVERVIEW 1
2 WIRELESS COMMUNICATION 2
2.1. Radio Frequency-its necessity 2
2.1.1. Brief Description of RF 2
2.1.2. Properties of Radio Frequency 3
3 REQUIREMENTS FOR RF COMMUNICATION 4
3.1 Power Supply 4
3.2 Regulated Power Supply 4
3.3 Diode Rectifier- Full wave bridge rectifiers 5
3.4 Capacitive Filter 6
3.5 RF Transmitter STT-433MHz 7
3.5.1. About the Transmitter 8
3.5.2. Features 8
3.5.3. Pin Description 8
3.6 Basic Application circuit of HT640 Encoder 9
3.7 RF Receiver STR-433MHz 10
3.7.1. Pin Description 11
3.8 Basic Application circuit of HT648L Decoder 12
4 MICROCONTROLLER 13
4.1. General Description 13
4.1.1 Features of ATMEL 89C51 Microcontroller 13
4.1.2 Block Diagram ATMEL 89C51 Microcontroller 14
4.1.3 Pin Diagram ATMEL 89C51 Microcontroller 15
4.1.4 Pin Description of ATMEL 89C51 Microcontroller 15
5 H-BRIDGE 17
7 WIRELESS CAMERA FOR IMAGE TRANSMISSION 20
7.1. RF Transmitter (Remote) Block Diagram 20
7.2. RF Receiver (Remote) Block Diagram 21
8 WORKING OF THE PROJECT 22
8.1. RF Transmitter (Remote) 22
8.2. RF Receiver (Robot) 23
9.1. Programming Algorithm 25
9.2. Project Code 26
10 RESULTS 28
ADVANTAGES AND DISADVANTAGES 29
The aim of this project is to control the operation of movement of a remote controlled robot to detect metals and to view the images surrounding the robot.
The main objectives of this project are to use radio frequency bands.
Wireless communication, as the term implies, allows information to be exchanged between two devices without the use of wire or cable. A wireless keyboard sends information to the computer without the use of a keyboard cable; a cellular telephone sends information to another telephone without the use of a telephone cable. Changing television channels, opening and closing a garage door, and transferring a file from one computer to another can all be accomplished using wireless technology. In all such cases, information is being transmitted and received using electromagnetic energy, also referred to as electromagnetic radiation. One of the most familiar sources of electromagnetic radiation is the sun; other common sources include TV and radio signals, light bulbs and microwaves.
Radio frequency is a frequency or rate of oscillation within the range of about 3Hz to 300 GHz. This range corresponds to frequency of alternating current electrical signals used to produce and detect radio waves.Since most of this range is beyond the vibration rate the most mechanical systems can respond to, RF usually refers to oscillations in electrical circuits. RF is widely used because it does not require any line of sight, less distortions and no interference. Examples include, Cordless and cellular telephone, radio and television broadcast stations, satellite communications systems, and two-way radio services all operate in the RF spectrum.
Radio frequency (abbreviated RF) is a term that refers to alternating current (AC) having characteristics such that, if the current is input to an antenna, an electromagnetic (EM) field is generated suitable for wireless broadcasting and/or communications. These frequencies cover a significant portion of the electromagnetic radiation spectrum, extending from nine kilohertz (9 kHz),the lowest allocated wireless communications frequency (it's within the range of human hearing), to thousands of gigahertz(GHz).
When an RF current is supplied to an antenna, it gives rise to an electromagnetic field that propagates through space. This field is sometimes called an RF field; in less technical jargon it is a "radio wave." Any RF field has a wavelength that is inversely proportional to the frequency.
As the frequency is increased beyond that of the RF spectrum, EM energy takes the form of infrared (IR), visible, ultraviolet (UV), X rays, and gamma rays. ), X rays, and gamma rays. Many types of wireless devices make use of RF fields.Some wireless devices operate at IR or visible-light frequencies, whose electromagnetic wavelengths are shorter than those of RF fields.
Electrical currents that oscillate at RF have special properties not shared by direct current signals:
1. One such property is the ease with which it can ionize air to create a conductive path through air. This property is exploited by 'high frequency' units.
RF communication is required for the transmission of radio waves from RF transmitter (remote) to RF receiver (robot) to enable the movement of the robot in this project. The basic requirements for the RF communication used in this project are as follows:
The input to the circuit is applied from the regulated power supply. The a.c. input i.e., 230V from the mains supply is step down by the transformer to 12V and is fed to a rectifier. The output obtained from the rectifier is a pulsating d.c voltage. So in order to get a pure d.c voltage, the output voltage from the rectifier is fed to a filter to remove any a.c components present even after rectification. Now, this voltage is given to a voltage regulator to obtain a pure constant dc voltage.
A variable regulated power supply, also called a variable bench power supply, is one where you can continuously adjust the output voltage to your requirements. Varying the output of the power supply is the recommended way to test a project having doubled checked parts placement against0* circuit drawings and the parts placement guide. Most digital logical circuits and processors need a 5 volt power supply . to use these parts we need to build a regulated 5 volt source . Usually you start with an unregulated power supply ranging from 9 volts to 24 volts DC. To make a 5 volt power supply, we use a LM7805 voltage regulator IC (Integrated circuit) . the IC is shown below .
Figure 3.1: Regulated Power Supply
The LM7805 is simple to use. you simply connect the positive lead of your unregulated DC power supply (anything from 9 VDC to 24 VDC ) to the Input pin , connect the negative lead to the Common pin and then when you turn on the power , you get a 5 volt supply from the Output pin.
The need for a centre tapped power transformers is eliminated in the bridge rectifier .it contains four diodes D1 , D2 , D3 and D4 connected to from bridge as shown below.
Figure 3.2: Full wave bridge rectifier
The a. c. supply to be rectified is applied to the diagonally opposite ends of the bridge through the transformer. Between other two ends of the bridge , the load resistance RL is connected .
A capacitive filter helps in reducing the ripples. A capacitive filter is shown below.
Figure 3.3: Circuit Diagram and the respective output waveforms of Capacitive Filter
3.5 RF Transmitter STT-433MHz
Figure 3.4: RF Transmitter STT-433MHz
Figure 3.5: Transmitter circuit
The encoder parallel bit data into serial bit data i.e, the antenna in the transmitter transmits the signal to the receiver, which is of single bit through the medium of air.
Figure 3.6: HT640 Encoder
Table 3.1: Pin description (HT640 Encoder)
Figure 3.7: RF Receiver STR-433MHz
The data is received by the RF receiver from the antenna pin and this data is available on the data pins. Two Data pins are provided in the receiver module. Thus, this data can be used for further applications.
Figure 3.8: Pin diagram of RF Receiver STR-433MHz
3.8 Basic Application circuit of HT648L Decoder
Figure 3.9: HT648L Decoder
Similarly, as the transmitter requires an encoder, the receiver module requires a decoder. The decoder used is HT648L from ^
Table 3.2: Pin Description (HT648L Decoder)
4.1. General Description
The AT89C51 is a low-power, high-performance CMOS 8-bit microcomputer with 4K bytes of Flash programmable and erasable read only memory (PEROM). The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard MCS-51 instruction set and pin out. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C51 is a powerful microcomputer which provides a highly-flexible and cost-effective solution to many embedded control applications.
Figure 4.1: Block Diagram of AT89C51 microcontroller
4.1.3. Pin Diagram ATMEL 89C51 Microcontroller
Figure 4.2: Pin Diagram of AT8951 microcontroller
Table 3: Alternate Functions of port 3
The assembly language program is written and this program has to be dumped into the microcontroller for the hardware kit to function according to the software. The program dumped in the microcontroller is stored in the Flash memory in the microcontroller.
An H-bridge is an electronic circuit which enables DC electric motors to be run forwards or backwards. These circuits are often used in robotics. H-bridges are available as integrated circuits, or can be built from discrete components.
Figure 5.1: Graphical representation of H-Bridge
An H-bridge is built with four switches (solid-state or mechanical). When the switches S1 and S4 (according to the first figure) are closed (and S2 and S3 are open) a positive voltage will be applied across the motor. By opening S1 and S4 switches and closing S2 and S3 switches, this voltage is reversed, allowing reverse operation of the motor
The H-Bridge arrangement is generally used to reverse the polarity of the motor, but can also be used to 'brake' the motor, where the motor comes to a sudden stop, as the motors terminals are shorted, or to let the motor 'free run' to a stop, as the motor is effectively disconnected from the circuit.
The following table summarizes operation –
Table 4: Operation of H-Bridge
The simplest form of a metal detector consists of an oscillator producing an alternating current that passes through a coil producing an alternating magnetic field. If a piece of electrically conductive metal is close to the coil, eddy currents will be induced in the metal, and this produces an alternating magnetic field of its own. If another coil is used to measure the magnetic field (acting as a magnetometer), the change in the magnetic field due to the metallic object can be detected.
Figure 6.1: Metal Detecting circuit
The portable small-sized camera has the ball-point pen appearance, photographing a particular location in secret is possible without exposure to others. The camera circuit part is connected to a wireless transmission device for outputting a signal by a cable. A wireless receiving device at a remote location from the wireless transmission device receives a signal of the wireless transmission device for outputting or recording.
STT - 433
Figure 7.1: Block Diagram of RF Transmitter (Remote)
Wireless Camera with voice transmission
Geared Motor - I
Geared Motor - II
Power – On
Figure 7.2: Block Diagram of RF Receiver (Remote)
This project (Remote Controlled Metal Detecting Robot with Image Transmission) consists of two sections-Transmitter section (Remote) and Receiver section (Robot).
8.1. RF Transmitter (Remote)
In the transmitter section (remote), we have the following components:
There are four switches for the movement of the robot in various directions like forward, backward, left and right. These four switches are connected to the RF encoder . The RF encoder is then connected to RF transmitter, which is thereby connected to the antenna for the transmission of the radio waves.
Depending on the switch that is been pressed (left, right, forward, and backward), the digital data from the switches is transferred to the RF encoder, which encodes this digital data into RF signals and transmits to the RF transmitter. This transmitter transmits the RF waves to the receiver (robot) through the antenna.
The receiver section consists of the following components:
In this receiver section, the RF receiver is connected to the RF decoder. This decoder is connected to the microcontroller, which is, in turn, connected to the H-Bridge. This H-Bridge is connected to the geared motors of the robot. Metal detecting circuit is also other separate sub-section on the receiver part. The wireless camera is placed separately on the receiver section to view the surroundings.
When the radio waves are transmitted from the transmitter (remote) to the receiver (robot), these waves are received by the RF receiver through the receiver antenna. From the RF receiver the signals are sent to RF decoder, which decodes these signals into digital data. This digital data is sent to the microcontroller, which, depending on the code written in it, enables either the upper H-Bridge or lower H-Bridge. This H-Bridge correspondingly activates the specified geared motors (Geared Motors-I or Geared motors-II). Power set –reset button is used for activating the receiver section. Metal detecting circuit is other sub-section on the receiver part.
As the robot moves in any specified direction and if a metal is been placed on the path of the robot., the inducting coil present at the lower side of the receiver section, which acts as a metal detecting coil, will detect the metal and activates the buzzer sound on the receiver section. The metal detection processes goes on by induction of eddy currents in the metal due to the variation in the magnetic fields of the two components-coils and metal.
The wireless camera is placed to view the images surrounding the robot to locate the position of the metal being detected. The images can be viewed on a television at the user location. When the robot moves the camera also moves as per the adjustment of the camera on the receiver section. This provides the view of the location of the robot. Whenever the metal is detected, which we can be aware by the sound of the buzzer on the receiver section, we view the location of the mine with the help of the surrounding view provided by the camera through a television placed at our location. This feature makes the project more specific in applications like for metal detecting and other applications
The AT89C51 is normally shipped with the on-chip Flash memory array in the erased state (that is, contents = FFH) and ready to be programmed. The programming interface accepts either a high-voltage (12-volt) or a low-voltage (VCC) program enable signal. The low-voltage programming mode provides a convenient way to program the AT89C51 inside the user’s system, while the high-voltage programming mode is compatible with conventional third party Flash or EPROM programmers. The AT89C51 is shipped with either the high-voltage or low-voltage programming mode enabled.
Before programming the AT89C51, the address, data and control signals should be set up according to the Flash programming mode table. To program the AT89C51, the following steps should be considered:
#define rfdata P1
The present project is implemented on Keil Uvision. In order to program the device, proload tool has been used to burn the program onto the microcontroller.
Figure 10.1: RF Receiver Section (Robot)
Figure 10.2: RF Transmitter Section (Remote)
Limitations in this project are
This remote controlled metal detecting robot with image transmission can be used for detection of mines in remote and others places also with an image view through the television, to know the location of the mine. Since whenever this robot passes through a mine, it detects the mine and produces a buzzer sound and thereby the location of the mine can be traced out by the television used.
With the help of microcontroller, remote and other intelligent control technologies embedded in the project offer the end user to easily access greater control of their products. The use of a camera helps to view the location under control. the project’s various surveillance appliances include the monitoring of the robot and thereby the view of the camera so as to observe the location being detected.
This project presents a metal detecting robot using RF communication with wireless audio and video transmission and it is designed and implemented with Atmel 89C51 MCU in embedded system domain.
The robot is moved in particular direction using switches and the images are captured along with the audio and images are watched on the television .Experimental work has been carried out carefully. The result shows that higher efficiency is indeed achieved using the embedded system. The proposed method is verified to be highly beneficial for the security purpose and industrial purpose.
The mine sensor worked at a constant speed without any problem despite its extension, meeting the specification required for the mine detection sensor. It contributed to the improvement of detection rate, while enhancing the operability as evidenced by completion of all the detection work as scheduled. The tests demonstrated that the robot would not pose any performance problem for installation of the mine detection sensor. On the other hand, however, the tests also clearly indicated areas where improvement, modification, specification change and additional features to the robot are required to serve better for the intended purpose. Valuable data and hints were obtained in connection with such issues as control method with the mine detection robot tilted, merits and drawbacks of mounting the sensor, cost, handling the cable between the robot and support vehicle, maintainability, serviceability and easiness of adjustments. These issues became identified as a result of our engineers conducting both the domestic tests and the overseas tests by themselves, and in this respect the findings were all the more practical.
 Raj Kamal, “Embedded Systems”, Pearson Education Publications, 2007.
 Mazzidi, “8051 Microcontroller and Embedded Systems”, Prentice Hall Publications, 2nd Edition, 2005.
 Edwin S.Grosvenor and Morgan Wesson,”Alexander Graham Bell: The Life and Times of the Man Who Invented the Telephone “, New York, Abrams, 1997.
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