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“RF CONTROLLED CAR”
A MINI-PROJECT REPORT
Submitted by
PATEL PARESHKUMAR A.(120810108003)
PADHIAR NIRMAL G. (120810108005)...
Venus International College of Technology, Bhoyan Rathod - Gandhinagar
Department of Electrical & Electronics Engineering
...
ACKNOWLEDGEMENT
The project “RF CONTROLLED CAR” could not have turned out into a
successful working model without the kind...
ABSTRACT
This project was about to study how the wireless technology has advanced in
today‟s world. Radio frequency contro...
List of Tables
Table No. Description Page No.
1.1 Frequency band 1
3.1 Pin function of L293D 19
3.2 Logic of driver IC 20
...
List of Figures
Figure No. Description Page No.
1.1 cosmetic treatment 3
1.2 RF chip inside the body for spy purpose 4
2.1...
Table of Contents
Acknowledgement i
Abstract ii
List of Tables iii
List of Figures iv
1 Introduction to Radio Frequency 1
...
3 RF Controlled Car 14
3.1 Basics 14
3.1.1 Radio frequency remote control 14
3.1.2 Radio Frequency Remote Controlled
Wirel...
Chapter – 1
Introduction to Radio Frequency
1.1 Introduction
Radio frequency (RF) is a rate of oscillation in the range of...
1.2 Special Properties of Radio Frequency
Electric currents that oscillate at radio frequencies have special properties no...
particular frequency band, while reducing oscillations at other frequencies outside the band.
Another method to isolate a ...
weapon that delivers electromagnetic energy at levels that injure human tissue. The inventor of
the death ray, Harry Grind...
between the electric and magnetic components of the field can be complex, and it is best to use
the field strength units d...
Chapter – 2
Radio Frequency generation and its side aspects
2.1 Generation of Radio Frequency
Radio frequency signal gener...
Free running RF signal generators: These signal generators are rarely used these days
as their frequency tends to drift. H...
Fig 2.2:-Block diagram of phase locked loop synthesizer
Fig 2.3:- Block Diagram of a Basic Direct Digital Synthesizer (DDS...
Fig 2.4:- Block diagram of a generic RF signal generator
The diagram shows a very simplified block diagram for an RF / Mic...
Control: Advanced processors are used to ensure that the RF and microwave signal
generator is easy to control and is also ...
Control: There are many options for controlling RF and microwave signal generators
these days. While they tend to have tra...
communication. The information which is being transmitted through the IR type of
communication technology is not secured a...
2.2.3 Applications
1. Radio waves have the longest wavelength among the EM waves: from a few centimetres
to several hundre...
Chapter-3
RF Controlled Car
3.1 Basics
3.1.1 Radio frequency remote control
Radio frequency controlled car is basically di...
3.2 Block diagram
Fig3.1 Block diagram of RF controlled car
The above shown figure is the block diagram of the entire radi...
3.3 Circuit diagram
The circuit if the robot car is divided into two parts (i). Transmitter and (ii) Receiver. The first
c...
Fig 3.3 Circuit diagram of RF receiver section circuit
The receiver section has three ICs and one receiver module. It cons...
Radio Frequency signals can travel longer distances than Infrared.
Only line of sight communication is possible through In...
Fig 3.5 Pins for ASK RF module
Transmitter
This is an ideal for remote control applications where low cost and longer rang...
RF Receiver 433 MHz ASK Features:
Integrated IF and data filters.
Receiver Frequency: 433.92 MHZ
Typical sensitivity: -110...
Fig 3.7 Pin diagram encoder IC (zoomed)
The encoder has four input lines. These lines are used to give input which we want...
A0 - A7: These are the input address pins used for secured transmission of this data. These pins
can be connected to VSS o...
Fig 3.8 Pin diagram of decoder
Fig 3.9 Pin diagram of decoder (zoomed)
Pin Description
A0~A11 (HT12F) -- Input pins for address A0~A11 setting. These pins can be externally set to
VSS or left o...
Fig 3.10 Pin diagram if driver IC L293D
Pin No. Pin Characteristics
1
Enable 1-2, when this is HIGH the left part of the I...
15 INPUT 4, when this pin is HIGH the current will flow though output 4
14 OUTPUT 4, this pin should be connected to one o...
3.4.5 Voltage Regulators
Voltage regulator IC's are the IC‟s that are used to regulate voltage. IC 7805 is a 5V Voltage
Re...
The schematic given below shows how to use a 7805 IC, there are 3 pins in IC 7805, pin 1 takes
the input voltage and pin 3...
Chapter- 4
Result and Analysis
4.1 Result
INPUT 1 INPUT 2 ENABLE 1,2 Result
0 0 1 Stop
0 1 1 Anti-clockwise rotation
1 0 1...
The car which has been designed in the project consisting of two modules namely: transmitter
and the receiver send the sig...
Chapter 5
Conclusion and future scope
5.1 Conclusion
A transmitter on the one side sends the radio signals to the receiver...
References
[1]http://www.radio-electronics.com/info/t_and_m/generators/radio-frequency-rf-signal-
generator.php
[2]http://...
A report on Rf controlled car
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A report on Rf controlled car

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An overlook to radio frequency and using it to make a DIY toy RF controlled car.

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A report on Rf controlled car

  1. 1. “RF CONTROLLED CAR” A MINI-PROJECT REPORT Submitted by PATEL PARESHKUMAR A.(120810108003) PADHIAR NIRMAL G. (120810108005) PATEL AKASH R. (120810108014) In fulfillment for the award of the degree Of BACHELOR OF ENGINEERING In Electrical & Electronics Engineering Venus International College of Technology, Bhoyan Rathod – Gandhinagar. Gujarat Technological University, Ahmadabad. April 2015.
  2. 2. Venus International College of Technology, Bhoyan Rathod - Gandhinagar Department of Electrical & Electronics Engineering April 2015 CERTIFICATE Date: 17/04/2015 This is to certify that the project entitled “RF CONTROLLED CAR” has been carried out by PATEL PARESHKUMAR A., PADHIAR NIRMAL G., PATEL AKASH R. within four walls of Venus International College of Technology under my guidance in fulfillment of the degree of Bachelor of Engineering in Electrical & Electronics Engineering (6th Semester) of Gujarat Technological University, Ahmedabad during the academic year 2014-15. Internal Guide: Head of the Department: Prof. RISHIKESH AGRAWAL Prof. P. K. Jani
  3. 3. ACKNOWLEDGEMENT The project “RF CONTROLLED CAR” could not have turned out into a successful working model without the kind support and help of many individuals and the collage itself. I would like to extend my sincere thanks to all of them. We are highly indebted to VENUS INTERNATIONAL COLLEGE OF TECHNOLOGY for their guidance and constant supervision as well as for providing necessary information regarding the project and also for their support in completing the project. Firstly we would like to express our gratitude towards the DIRECTOR of this college Dr. A.K.Chaturvedi and the HOD of electrical and electronics department: Prof. Pranav K. Jani for their kind co-operation and encouragement which helped us in completion of this project carried in the collage premise without experiencing hurdles. A great help and support was obtained from our internal guide Prof. Rishikesh Agrawal without whom the fault clearance at certain level would not have been possible. Our thanks and appreciations also goes to the colleague in developing the project and people who have willingly helped us out with their abilities. The last but not the least, a very special thanks to our parents and relatives for their moral support which gave us strength to make this project.
  4. 4. ABSTRACT This project was about to study how the wireless technology has advanced in today‟s world. Radio frequency controlled car is one such great example which always fantasizes the world about the exploring of the technology. Now-a-days the modern trend has made more emphasis on performing the tasks wirelessly. This in turns leaves a greater impact on the youth which motivates them to continue the progress and the inventions of the technology. This project basically deals with the operation on the performance of the car through the radio frequency signals. Transmitter at the senders end on transmitting the signal is thereby received by the receiver which acts as an order for the driver IC to carry out the following instructions. Any object which makes a motion wirelessly is a robot and so this car is too a robot which acts as an artificial intelligence performing the called out instructions. This project being on the basic level when carried out on the higher level can do wonders if used in the correct directions for the betterment of the nation and humanity.
  5. 5. List of Tables Table No. Description Page No. 1.1 Frequency band 1 3.1 Pin function of L293D 19 3.2 Logic of driver IC 20 4.1 Logic of driver IC 22 4.2 Direction of car 22
  6. 6. List of Figures Figure No. Description Page No. 1.1 cosmetic treatment 3 1.2 RF chip inside the body for spy purpose 4 2.1 Radio Frequency Generator 6 2.2 Block diagram of phase locked loop synthesizer 8 2.3 Block Diagram of a Basic Direct Digital Synthesizer (DDS) 8 2.4 Block diagram of a generic RF signal generator 9 3.1 Block diagram of RF controlled car 15 3.2 Circuit diagram of RF transmitter section circuit 16 3.3 Circuit diagram of RF receiver section circuit 17 3.4 ASK RF module 18 3.5 Pins for ASK RF module 19 3.6 pin diagram encoder IC 20 3.7 pin diagram encoder IC (zoomed 21 3.8 pin diagram of decoder 23 3.9 pin diagram of decoder (zoomed) 23 3.10 pin diagram if driver IC L293D 25 3.11 circuit of 7805 voltage regulator 27 3.12 IC 7805 voltage regulator 28
  7. 7. Table of Contents Acknowledgement i Abstract ii List of Tables iii List of Figures iv 1 Introduction to Radio Frequency 1 1.1 Introduction 1 1.2 Special Properties of Radio Frequency 2 1.3 Radio Communication 2 1.4 Working areas of Radio Frequencies 3 1.5 Main Objective 5 2 Radio Frequency generation and its side aspects 6 2.1 Generation of Radio Frequency 6 2.1.1 Types of RF signal generator 6 2.1.2 RF signal generator operation 8 2.2 Aspects 11 2.2.1 Advantages 12 2.2.2 Disadvantages 12 2.1.3 Applications 13
  8. 8. 3 RF Controlled Car 14 3.1 Basics 14 3.1.1 Radio frequency remote control 14 3.1.2 Radio Frequency Remote Controlled Wireless Car 14 3.2 block diagram 15 3.3 Circuit diagram 16 3.4 electronic components and modules used 18 3.4.1 3.4.1 HT12E encoder IC 19 3.4.2 HT12D decoder IC 21 3.4.3 Driver IC L293D 23 3.4.4 Voltage Regulators 25 4 Result and Analysis 4.1 Result 28 4.2 Analysis 29 5 Conclusion and future scope 30 5.1 Conclusion 30 5.2 Future Scope 30 5.3 References
  9. 9. Chapter – 1 Introduction to Radio Frequency 1.1 Introduction Radio frequency (RF) is a rate of oscillation in the range of around 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals. RF usually refers to electrical rather than mechanical oscillations; Although radio frequency is a rate of oscillation, the term "radio frequency" or its abbreviation "RF" are also used as a synonym for radio – i.e. to describe the use of wireless communication, as opposed to communication via electric wires. Examples include: Radio-frequency identification Radio frequency power and signal interface. Table 1.1 Frequency band
  10. 10. 1.2 Special Properties of Radio Frequency Electric currents that oscillate at radio frequencies have special properties not shared by direct current or alternating current of lower frequencies. The energy in an RF current can radiate off a conductor into space as electromagnetic waves (radio waves); this is the basis of radio technology. RF current does not penetrate deeply into electrical conductors but tends to flow along their surfaces; this is known as the skin effect. For this reason, when the human body comes in contact with high power RF currents it can cause superficial but serious burns called RF burns. RF currents applied to the body often do not cause the painful sensation of electric shock as do lower frequency currents. This is because the current changes direction too quickly to trigger depolarization of nerve membranes. RF current can easily ionize air, creating a conductive path through it. This property is exploited by "high frequency" units used in electric arc welding, which use currents at higher frequencies than power distribution uses. The ability to appear to flow through paths that contain insulating material, like the dielectric insulator of a capacitor. When conducted by an ordinary electric cable, RF current has a tendency to reflect from discontinuities in the cable such as connectors and travel back down the cable toward the source, causing a condition called standing waves, so RF current must be carried by specialized types of cable called transmission line.[2] 1.3 Radio Communication To receive radio signals an antenna must be used. However, since the antenna will pick up thousands of radio signals at a time, a radio tuner is necessary to tune into a particular frequency (or frequency range). This is typically done via a resonator – in its simplest form, a circuit with a capacitor and an inductor form a tuned circuit. The resonator amplifies oscillations within a
  11. 11. particular frequency band, while reducing oscillations at other frequencies outside the band. Another method to isolate a particular radio frequency is by oversampling (which gets a wide range of frequencies) and picking out the frequencies of interest, as done in software defined radio. The distance over which radio communications is useful depends significantly on things other than wavelength, such as transmitter power, receiver quality, type, size, and height of antenna, mode of transmission, noise, and interfering signals. 1.4 Working areas of Radio Frequencies Radio frequency (RF) energy, in the form of radiating waves or electrical currents, has been used in medical treatments for over 75 years, generally for minimally invasive surgeries, using radiofrequency and cryoablation, including the treatment of sleep apnea. Magnetic resonance imaging (MRI) uses radio frequency waves to generate images of the human body. Radio frequencies are sometimes used as a form of cosmetic treatment that can tighten skin, reduce fat, or promote healing. Before After Fig 1.1 Cosmetic treatment In weapon areas, a heat ray is a RF harassment device that makes use of microwave radio frequencies to create an unpleasant heating effect in the upper layer of the skin. A publicly known heat ray weapon called the Active Denial System was developed by the US military as an experimental weapon to deny the enemy access to an area. Also, see death ray which is a heat ray
  12. 12. weapon that delivers electromagnetic energy at levels that injure human tissue. The inventor of the death ray, Harry Grindell Matthews, claims to have lost sight in his left eye while developing his death ray weapon based on a primitive microwave magnetron from the 1920s Radio frequency has also been used in the military areas for spying and keeping a track on their mission and their objectives. The equipment is so small that it can fit anywhere and everywhere. Usually they are put inside the body to keep it as a secret. Fig 1.2:- RF chip inside the body for spy purpose Since radio frequency radiation has both an electric and a magnetic component, it is often convenient to express intensity of radiation field in terms of units specific to each component. The unit volts per meter (V/m) is used for the electric component, and the unit amperes per meter (A/m) is used for the magnetic component. One can speak of an electromagnetic field, and these units are used to provide information about the levels of electric and magnetic field strength at a measurement location. Another commonly used unit for characterizing an RF electromagnetic field is power density. Power density is most accurately used when the point of measurement is far enough away from the RF emitter to be located in what is referred to as the far field zone of the radiation pattern. In closer proximity to the transmitter, i.e., in the "near field" zone, the physical relationships
  13. 13. between the electric and magnetic components of the field can be complex, and it is best to use the field strength units discussed above. Power density is measured in terms of power per unit area, for example, mill watts per square centimetre (mW/cm²). When speaking of frequencies in the microwave range and higher, power density is usually used to express intensity since exposures that might occur would likely be in the far field zone. 1.5 Main Objective Communication systems play a major role in maintaining communication between humans or organizations or institutions or even people get entertainment programs or news or other television or radio broadcasting programs via wired or wireless communication systems. To overcome disadvantages of wired communications, advancement in technology has resulted in the development of most advanced wireless communication systems including wireless radio frequency technology, infrared technology, GSM technology, and so on. These wireless communication systems can be used to transmit different types of signals from transmitting end to receiving end. The control signal from transmitter is sent to the receiver which is connected to an object or device or vehicle that is to be remotely controlled. For example, IR remote is used to control TV remotely. Similarly, this article mentions about a wirelessly controlled robot controlled using radio frequency technology. A robot which would perform tasks assigned to it through rf signals. Being the part of the wireless technology this would serve an immense ease to the people to do some stuff without and mechanical energy lost. Now-a-days the technology growing very fast the adaption of this technology will become inevitable in the near future.
  14. 14. Chapter – 2 Radio Frequency generation and its side aspects 2.1 Generation of Radio Frequency Radio frequency signal generators (RF signal generators) are a particularly useful item of test equipment widely used in RF microwave design and test applications. These microwave and RF signal generators come in a variety of forms and with a host of facilities and capabilities. In order to gain the most from any RF signal generator or microwave signal generator, it is necessary to have an understanding of its operation and the capabilities it possesses. Fig 2.1:- Radio Frequency Generator 2.1.1 Types of RF signal generator It is possible to design radio frequency signal generators in a variety of ways. Also with developments that have been made in electronics circuitry over the years, different techniques have evolved. It can be said that there are two forms of signal generator that can be used:
  15. 15. Free running RF signal generators: These signal generators are rarely used these days as their frequency tends to drift. However they do have the advantage that the signal produced is very clean and does not have the level of noise (phase noise) either side of the main signal that is present on some other radio frequency signal generators. Some signal generators used a form of frequency locked loop to provide a means of adding some frequency stability while still retaining the very low levels of phase noise. Again, these are not common these days because the performance of RF signal generators using frequency synthesizer technology has considerably improved. Synthesized radio frequency signal generators: Virtually all radio frequency signal generators used today employ frequency synthesizers. Using this technique enables frequencies to be entered directly from a keypad, or via remote control and it also enables the output signal to be determined very accurately. The accuracy being dependent upon either an internal reference oscillator that can have a very high degree of accuracy, or the signal can be locked to an external frequency reference which can be exceedingly accurate. There are two main techniques that are used within synthesized RF signal generators: Phase locked loop synthesizer: Phase locked loop synthesizers are used within most RF signal generators as they enable signals to be generated over a wide range of frequencies with a relatively low level of spurious signals. Phase locked loop synthesizer technology is well developed and enables high performance RF signal generators to be produced using them. Direct Digital Synthesizer, DDS: Direct digital synthesis techniques may be used in RF signal generators. They enable very fine frequency increments to be achieved relatively easily. However the maximum limit of a DDS is normally much lower than the top frequencies required for the signal generator, so they are used in conjunction with phase locked loops to give the required frequency range.
  16. 16. Fig 2.2:-Block diagram of phase locked loop synthesizer Fig 2.3:- Block Diagram of a Basic Direct Digital Synthesizer (DDS). 2.1.2 RF signal generator operation In order to understand the operation of a generic microwave or RF signal generator it is useful to understand what is included in terms of a basic block diagram.
  17. 17. Fig 2.4:- Block diagram of a generic RF signal generator The diagram shows a very simplified block diagram for an RF / Microwave signal generator. From this, it can be seen that the generator has a few major blocks within it: Oscillator: The most important block within the RF signal generator is the oscillator itself. This can be any form of oscillator, but today it would almost certainly be formed from a frequency synthesizer. This oscillator would take commands from the controller and be set to the required frequency. Amplifier: The output from the oscillator will need amplifying. This will be achieved using a special amplifier module. This will amplify the signal, typically to a fixed level. It would have a loop around it to maintain the output level accurately at all frequencies and temperatures. Attenuator: An attenuator is placed on the output of the signal generator. This serves to ensure accurate source impedance is maintained as well as allowing the generator level to be adjusted very accurately. In particular the relative power levels i.e. when changing from one level to another are very accurate and represent the accuracy of the attenuator. It is worth noting that the output impedance is less accurately defined for the highest signal levels where the attenuation is less.
  18. 18. Control: Advanced processors are used to ensure that the RF and microwave signal generator is easy to control and is also able to take remote control commands. The processor will control all aspects of the operation of the test equipment. RF signal generator functions: Microwave and RF signal generators are able to offer a large variety of functions and facilities these days. These include some that are detailed below: Frequency range: Naturally the frequency range of the RF signal generator is of paramount importance. It must be able to cover all the frequencies that are likely to need to be generated. For example when testing a receiver in an item of equipment, be it a mobile phone or any other radio receiver, it is necessary to be able to check not only the operating frequency, but other frequencies where the issues such as image rejection, etc. Output level: The output range for an RF and microwave signal generator is normally controlled to a relatively high degree of accuracy. The output within the generator itself is maintained at a constant level and then passed through a high grade variable attenuator. These are normally switch to give the highest degree of accuracy. The range is normally limited at the top end by the final amplifier in the RF signal generator. Modulation: Some RF or microwave signal generators have inbuilt oscillators that can apply modulation to the output signal. Others also have the ability to apply modulation from an external source. With modulation formats for applications such as mobile communications becoming more complicated, so the capabilities of RF signal generators have had to become more flexible, some allowing complex modulation formats such as QPSK, QAM and the like. Signal generators that support complex modulation are often referred to as vector signal generators. Sweep: On some RF signal generators it is necessary to sweep the signal over a range. Some generators offer this capability.
  19. 19. Control: There are many options for controlling RF and microwave signal generators these days. While they tend to have traditional front panel controls, there are also many options for remote control. Most items of laboratory bench test equipment come with GPIB fitted as standard, but options such as RS-232, and Ethernet / LXI. Rack technologies where instrument cards are slotted into a rack with other items of test equipment are also popular. The first of these was VXI, but cheaper options such as PXI and PXI express are more widely used. Radio frequency signal generators are a form of electronic test equipment found in virtually every radio frequency design or test laboratory. These signal generators are used wherever an RF signals needs to be supplied to a circuit or unit that is being developed or tested. As such RF signal generators are essential items for RF development and testing. 2.2 Aspects A car wherein the main role is played by rf is called a radio frequency controlled car. This is a wirelessly controlled car as the name suggests wherein the signals are transmitted and received through the antenna on both the sides. There will be two parts in this complete model i.e. transmitter and the receiver. The transmitter will send the signal which will be received by the receiver and the tasks instructed by the transmitter will be executed. Here RF method to run the car is selected because it can travel a longer area as compared to the IR type. Radio frequency are in the waveform which becomes easy for the signal to get transmitted as they can reach to the receiver via reflection through the walls. The waveforms do not get distracted so easily on getting hit to the wall. In the IR type there has to be a sight communication between the transmitter and the receiver to communicate. IR communications are therefore mainly used in the remote control for the television, air conditions etc. in this type of transmission if the communicating path is obstructed by any object be it an opaque, translucent or a transparent device it gets distorted and the complete information is not transferred. This is also considered as one of the main disadvantages that it needs a sight
  20. 20. communication. The information which is being transmitted through the IR type of communication technology is not secured as the chance of getting distorted and being lost is more than compared to that of the RF type communication system. The transmission of the information being in the sinusoidal waveform doesn‟t get distorted as the have the tendency to transmit the signal with the help of reflection. If the number of reflections or hitting increases than some certain decided value the chances of loss of information may arise. 2.2.1 Advantages: The first advantage of RF over IR is in the improved user experience and much better range. RF does not require the typical IR point-and-shoot action anymore. You can walk anywhere in the house and use the remote. The RF remote control can transmit its signal through walls, doors and furniture, which makes it possible to install the set top box in a closed cabinet or a closet. Another benefit of RF over IR is that RF allows two-way communication and enables a status display on the remote. This direct interaction with the end-user will allow the service provider to send messages to the remote control display. The combination of non-line-of-sight operation and bi-directional communications also enables one of the most nerve soothing features of RF remote controls - a simple yet efficient “find-me” function[4] 2.2.2 Disadvantages: The main disadvantage of radio frequency or radio waves is that it is harmful to health and skin as well. Large doses of radio waves are believed to cause cancer, leukemia and other disorders. Exposures to RFs have been unofficially linked to sleep disorders, headaches, and other neurological problems.[4]
  21. 21. 2.2.3 Applications 1. Radio waves have the longest wavelength among the EM waves: from a few centimetres to several hundred metres. 2. Radio waves are produced by electric current oscillating in electric circuit containing a coil and a capacitor 3. They are used radio and television communication. 4. Radio waves act as carrier waves for the audio signals and video signals. The advantage is that the radio signals travel at a speed of 3.0*10^8 m/s. The process of combining audio and video signal is known as modulation. Television transmission uses very high frequency (VHF) or ultra-high frequency (UHF) radio frequency.
  22. 22. Chapter-3 RF Controlled Car 3.1 Basics 3.1.1 Radio frequency remote control Radio frequency controlled car is basically divided into two parts i.e. transmitter and the receiver. Radio frequency remote consists of transmitter at the transmitter end and a receiver at the receiver end connected, which is connected to a remote circuit that is to be controlled. A control signal is transferred from transmitter end in the form of electromagnetic waves or radio waves such that to control the device remotely, which is connected to the receiver end. This control signal is transmitted using electromagnetic waves or radio waves of radio frequency. Thus, the control signal received at the receiver end can be used to control.[3] 3.1.2 Radio Frequency Remote Controlled Wireless Car Radio frequency controlled robotic vehicle is designed using a robotic vehicle that is interfaced with radio frequency remote control. RF transmitter is used by control panel or controlling person and RF receiver is connected to the robotic vehicle that is to be controlled remotely. Radio frequency remote control works over an adequate range by facilitating with proper antenna. [3]
  23. 23. 3.2 Block diagram Fig3.1 Block diagram of RF controlled car The above shown figure is the block diagram of the entire radio frequency controlled car. Here we are using an ASK transmitter receiver module. Remote which is having a transmitter is used to transmit the signal from one point to another. There are controlling switches used which are used pinpoint which way the car should take a turn and move. The supply when applied to the switches it gives to the encoder which encodes the signal .this encoded signal is then sent to the RF-Tx transmitter which is used to perform the task of transmitting the signal from one end to the receiver. The antenna is attached on both the modules which acts as a source to catch and transmit the signals. The signal which is transmitted by the transmitter is caught by the receiver in the receiving section with the help of the antenna. This signal is then sent to the decoder IC .The decoder sends the signal to the motor driver which then ultimately drives the motor connected to it.
  24. 24. 3.3 Circuit diagram The circuit if the robot car is divided into two parts (i). Transmitter and (ii) Receiver. The first circuit diagram is the transmitter and followed by the receiver. The receiver has been supplied with a voltage regulator IC 7805 which will give a 5 volt DC supply to the circuit from 12 volt DC main supply. In the transmitter section circuit has there are 5 switches used in the circuit for controlling the direction of the car. Four of them are used to give the direction instruction to the receiver and the fifth switch is used to switch on or off the switching control. It acts as the main switch for the transmitter section. The diode in the circuit with the help of the logic gates using binary language instructs the receiver for performing the tasks. Transmitter uses an encoder which IC i.e. HT-12E which encodes the voltage signal in the binary language which is the connected to the switches. There is a transmitter ASK-RF-TX used which is capable of sending data to the other end.[3] Fig 3.2 Fig3.2 Circuit diagram of RF transmitter section circuit
  25. 25. Fig 3.3 Circuit diagram of RF receiver section circuit The receiver section has three ICs and one receiver module. It consists of a decoder HT-12D, driver IC L293D, voltage regulator IC 7805 and the receiver module ASK-RF-Rx. The working of the car starts with the 7805IC voltage regulator wherein the input voltage given to it is 12 volt DC and it converts that 12 volt to 5 volt DC. There are two 16 pins ICs as encoder and the decoder which are connected to the switches and transmitter and to the driver IC along with the voltage regulator respectively. Each of the IC has its own basic properties and functions which have been discussed in detail in the below section. Wireless transmission can be done by using 433 MHz or 315MHz ASK RF Transmitter and Receiver modules. In these modules digital data is represented by different amplitudes of the carrier wave, hence this modulation is known as Amplitude Shift Keying (ASK). Radio Frequency (RF) transmission is more strong and reliable than Infrared (IR) transmission due to following reasons:
  26. 26. Radio Frequency signals can travel longer distances than Infrared. Only line of sight communication is possible through Infrared while radio frequency signals can be transmitted even when there is an obstacle. Infrared signals will get interfered by other IR sources but signals on one frequency band in RF will not interfered by other frequency RF signals. 3.4 electronic components and modules used:- There are many components being used in this project and they are as follows:- 8 Resistors of 560Ω HT12E encoder IC and HT12D decoder IC, ASK RF transmitter and receiver, Driver IC Button Switch BO Motor Robotic Wheels and a battery Voltage regulator 7805 3.4.1 ASK RF transmitter and receiver The ASK transmitter Module employs a crystal-stabilized oscillator, ensuring accurate frequency control for best range performance. There is no requirement of external RF components except Antenna. Amplitude-shift keying (ASK) is a form of amplitude modulation that represents digital data as variations in the amplitude of a carrier. In an ASK system, the binary symbol 1 is represented by transmitting a fixed-amplitude carrier wave and fixed frequency for a bit duration of T seconds. If the signal value is 1 then the carrier signal will be transmitted; otherwise, a signal value of 0 will be transmitted. Fig 3.4 ASK RF module
  27. 27. Fig 3.5 Pins for ASK RF module Transmitter This is an ideal for remote control applications where low cost and longer range is required. The transmitter operates from a 3-12V supply, making it ideal for battery-powered applications. The transmitter employs a SAW-stabilized oscillator, ensuring accurate frequency control for best range performance. Range of transmitter is approx 100 meters. RF Transmitter 433 MHz ASK Features: Frequency Range: 433.92 MHZ. Supply Voltage: 3~12V. Output Power : 4~16dBm Receiver This is an Hybrid 433Mhz RF receiver module and is ideal for short-range wireless control applications where quality is a primary concern. The receiver module requires no external RF components except for the antenna. The super-regenerative design exhibits exceptional sensitivity at a very low cost.
  28. 28. RF Receiver 433 MHz ASK Features: Integrated IF and data filters. Receiver Frequency: 433.92 MHZ Typical sensitivity: -110dBm Supply Current: 2.85mA IF Frequency: 280KHz Low power consumption. Operation voltage: 5 Volts. 3.4.2 HT12E encoder IC HT12E is a 212 series encoder IC widely used in remote control and very common among Radio Frequency RF applications. This HT12E IC capable of converting 12 bit Parallel data inputs into serial outputs. These bits are classified into 8 (A0-A7) address bits and 4(AD0-AD3) data bits. Using the address pins we can provide 8 bit security code for secured data transmission between the encoder and the decoder. The encoder and decoder should use the same address and data format. HT12E is capable of operating in a wide Voltage range from 2.4V to 12V and also consists of a built in oscillator. The figure below will clear this Fig 3.6 Pin diagram encoder IC
  29. 29. Fig 3.7 Pin diagram encoder IC (zoomed) The encoder has four input lines. These lines are used to give input which we want to encode. In encoding, we are wrapping up the data which means if we want to send a binary signal „1001‟ to other end, we have to make data pins as „1001‟. Now, to make data pin like this, what we need to do is to give high or 5 volts (which in digital means „1‟) to pins „D0‟ and „D3‟ while we have to provide pins „D1‟ and „D2‟ with 0 volt. (Ground). This altogether gives us „1001‟ which is transmitted out from the „Data out‟ pin of the HT12E. The input given to data pin is in parallel form which is being transmitted into serial form from the data output pin. PIN DESCRIPTION OF IC HT12E: The pin Description of the IC HT12E was pretty simple to understand with total of 18 pins. VDD and VSS: Positive and negative power supply pins. OSC1 and OSC2: Input and output pins of the internal oscillator present inside the IC. TE: This pin is used for enabling the transmission; a low signal in this pin will enable the transmission of data bits.
  30. 30. A0 - A7: These are the input address pins used for secured transmission of this data. These pins can be connected to VSS or left open. AD0 - AD3: This pins are feeding data into the IC. These pins may be connected to VSS or may be left open for sending LOW or HIGH bits to the encoder. DOUT: The output of the encoder can be obtained through this pin and can be connected to the RF transmitter. Working of IC HT12E: HT12E starts working with a low signal on the TE pin. After receiving a low signal the HT12E starts the transmission of 4 data bits. And the output cycle will repeat based on the status of the TE pin in the IC. If the TE pin retains the low signal the cycle repeats as long as the low signal in the TE pin exists. The encoder IC will be in standby mode if the TE pin is disabled and thus the status of this pin was necessary for encoding process. The address of these bits can be set through A0 - A7 and the same scheme should be used in decoders to retrieve the signal bits. 3.4.3 HT12D decoder IC HT12D is a 212 series decoder IC for remote control applications. It is commonly used for radio frequency (RF) wireless applications. By using the paired HT12E encoder and HT12D decoder we can transmit 12 bits of parallel data serially. HT12D simply converts serial data to its input to 12 bit parallel data. These 12 bit parallel data is divided in to 8 address bits and 4 data bits. Using 8 address bits we can provide 8 bit security code for 4 bit data and can be used to address multiple receivers by using the same transmitter. The serial input data is compared with the local addresses three times continuously. The input data code is decoded when no error or unmatched codes are found. A valid transmission in indicated by a high signal at VT pin.
  31. 31. Fig 3.8 Pin diagram of decoder Fig 3.9 Pin diagram of decoder (zoomed)
  32. 32. Pin Description A0~A11 (HT12F) -- Input pins for address A0~A11 setting. These pins can be externally set to VSS or left open. A0~A7 (HT12D) -- Input pins for address A0~A7 setting. These pins can be externally set to VSS or left open. D8~D11 (HT12D) -- Output data pins, power-on state is low. DIN Serial data input pin VT Valid transmission, active high OSC1 Oscillator input pin OSC2 Oscillator output pin VSS - Negative power supply, ground VDD - Positive power supply 3.4.4 Driver IC L293D:- Motor Driver ICs are primarily used in autonomous robotics only. Also most microprocessors operate at low voltages and require a small amount of current to operate while the motors require a relatively higher voltages and current. Thus current cannot be supplied to the motors from the microprocessor. This is the primary need for the motor driver IC. The L293D IC receives signals from the decoder and transmits the relative signal to the motors. It has two voltage pins, one of which is used to draw current for the working of the L293D and the other is used to apply voltage to the motors. The L293D switches it output signal according to the input received from the decoder. For Example: If the decoder sends a 1(digital high) to the Input Pin of L293D, then the L293D transmits a 1(digital high) to the motor from its Output Pin. An important thing to note is that the L293D simply transmits the signal it receives. It does not change the signal in any case. The L293D is a 16 pin IC, with eight pins, on each side, dedicated to the controlling of a motor. There are 2 INPUT pins, 2 OUTPUT pins and 1 ENABLE pin for each motor.
  33. 33. Fig 3.10 Pin diagram if driver IC L293D Pin No. Pin Characteristics 1 Enable 1-2, when this is HIGH the left part of the IC will work and when it is low the left part won‟t work. So, this is the Master Control pin for the left part of IC 2 INPUT 1, when this pin is HIGH the current will flow though output 1 3 OUTPUT 1, this pin should be connected to one of the terminal of motor 4,5 GND, ground pins 6 OUTPUT 2, this pin should be connected to one of the terminal of motor 7 INPUT 2, when this pin is HIGH the current will flow though output 2 8 VC, this is the voltage which will be supplied to the motor. So, if you are driving 12 V DC motors then make sure that this pin is supplied with 12 V 16 VSS, this is the power source to the IC. So, this pin should be supplied with 5 V
  34. 34. 15 INPUT 4, when this pin is HIGH the current will flow though output 4 14 OUTPUT 4, this pin should be connected to one of the terminal of motor 13,12 GND, ground pins 11 OUTPUT 3, this pin should be connected to one of the terminal of motor 10 INPUT 3, when this pin is HIGH the current will flow though output 3 9 Enable 3-4, when this is HIGH the right part of the IC will work and when it is low the right part won‟t work. So, this is the Master Control pin for the right part of IC Table 3.1 Pin functions of L293D Now depending upon the values of the Input and Enable the motors will rotate in either clockwise or anticlockwise direction with full speed (when Enable is HIGH) or with less speed (when Enable is provided with PWM). Let us assume for Left Motor when Enable is HIGH and Input 1 and Input 2 are HIGH and LOW respectively then the motor will move in clockwise direction. So the behaviour of the motor depending on the input conditions will be as follows: INPUT 1 INPUT 2 ENABLE 1,2 Result 0 0 1 Stop 0 1 1 Anti-clockwise rotation 1 0 1 Clockwise rotation 1 1 1 Stop 0 1 50% duty cycle Anti-clockwise rotation with half speed 1 0 50% duty cycle Clockwise rotation with half speed Table 3.2 Logic of driver IC
  35. 35. 3.4.5 Voltage Regulators Voltage regulator IC's are the IC‟s that are used to regulate voltage. IC 7805 is a 5V Voltage Regulator that restricts the voltage output to 5V and draws 5V regulated power supply. It comes with provision to add heat sink. The maximum value for input to the voltage regulator is 35V. It can provide a constant steady voltage flow of 5V for higher voltage input till the threshold limit of 35V. If the voltage is near to 7.5V then it does not produce any heat and hence no need for heat sink. If the voltage input is more, then excess electricity is liberated as heat from 7805. Fig 3.11:-circuit of 7805 voltage regulator It regulates a steady output of 5V if the input voltage is in rage of 7.2V to 35V. Hence to avoid power loss try to maintain the input to 7.2V. In some circuitry voltage fluctuation is fatal (for e.g. Microcontroller), for such situation to ensure constant voltage IC 7805 Voltage Regulator is used. IC 7805 is a series of 78XX voltage regulators. It‟s a standard, from the name the last two digits 05 denotes the amount of voltage that it regulates. Hence a 7805 would regulate 5v and 7806 would regulate 6V and so on.
  36. 36. The schematic given below shows how to use a 7805 IC, there are 3 pins in IC 7805, pin 1 takes the input voltage and pin 3 produces the output voltage. The GND of both input and out are given to pin 2. Fig 3.12 IC 7805 voltage regulator
  37. 37. Chapter- 4 Result and Analysis 4.1 Result INPUT 1 INPUT 2 ENABLE 1,2 Result 0 0 1 Stop 0 1 1 Anti-clockwise rotation 1 0 1 Clockwise rotation 1 1 1 Stop 0 1 50% duty cycle Anti-clockwise rotation with half speed 1 0 50% duty cycle Clockwise rotation with half speed Table 4.1:- logic of driver IC Here the above table which is been shown gives the logic calculation of the instruction that are given. As the instruction that are given to the driver IC it gives the directional rotation to the motor and thus when two motor are rotate in certain direction the car also moves in its specified direction. Left Motor Direction Right Motor Direction Direction of Car Forward Forward Forward Forward Backward Right Backward Forward Left Backward Backward Backward Table 4.2 Direction of the car
  38. 38. The car which has been designed in the project consisting of two modules namely: transmitter and the receiver send the signals from one end to another and due to this the motor on getting the signals the motor drives in either forward or reverse direction. If both the motor i.e. left and right moves in the forward direction then the direction of the car is in the forward direction. When the left motor moves in the forward direction and the right motor in the reversed direction then the resultant direction of the car will be in the right direction. The left motor moving in the reversed direction and the right motor in the forward direction then the final direction of the car will be in the left direction. And finally when both the motor i.e. left and the right move in the reversed direction then the ultimately direction of the car will be in the reversed direction. 4.2 Analysis From the project made it is understood that the use of the radio frequency can be used in the driving a simple robot car with the use of transmitter and receiver. The driver IC which is being connected to the decoder is also a great help to the project which can get programmed and can give out the called instruction for various occasions signaled by the transmitter with the help of antenna and the encoder. The voltage regulator on getting a power supply gives out a stable dc voltage of 5 volt. This prevents the other components especially the decoder and the receiver module from the getting damaged. The led in the receiver circuit gives an ease in understanding about the receiving of the signal from the transmitter end. This led when glows it indicates that the signal is transmitted.
  39. 39. Chapter 5 Conclusion and future scope 5.1 Conclusion A transmitter on the one side sends the radio signals to the receiver end. The antenna on both the side of the module are used as a help to catch the signals which are been transmitted through the transmitter. The receivers on receiving the signal with the help of the decoder decode the signal and are transmitted to the motor driver IC. The motors which are connected to the driver IC on getting the logic signals turns on and gives the direction to the car. 5.2 Future Scope Radio frequency which helps in the communication of the information has increased its value for the use of the same in future. With the advancement of technology in the radio frequency a gesture control robot is one of the finest projects which can be worked upon. Herein the gestures gives out by the person are sensed by the RF module which performs the task as shown by the gestures.
  40. 40. References [1]http://www.radio-electronics.com/info/t_and_m/generators/radio-frequency-rf-signal- generator.php [2]http://en.wikipedia.org/wiki/Radio_frequency [3]https://www.mepits.com/project/235/DIY-Projects/How-to-Make-a-Remote-Control-Car [4]https://books.google.co.in/books?id=U8Me3gvSV4MC&pg=PA132&dq=advantages+of+radi o+signals&hl=en&sa=X&ei=ScQkVf_zHsWouwTp2oHADg&ved=0CEIQ6AEwBw#v=onepag e&+q=advantages%20of%20radio%20signals&f=false

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