1.Department of Electrical Engineering Page 1 CHAPTER 1 INTRODUCTION 1.0 INTRODUCTION:- Remote control facilitates the operation of Induction Motor regulators around the home or other places. It provides a system that is simple to understand and also to operate, a system that would be reliable and easy to maintain and durable irrespective of its usage. It adds more comfort to everyday living by removing the inconvenience of having to move around to operate a Induction Motor . The first remote control, called lazy bones was developed in 1950 by Zenith Electronics Corporation (then known as Zenith Radio Corporation). The device was developed quickly, and it was called Zenith space command, the remote went into production in the fall of 1956, becoming the first practical wireless remote control device . Today, remote control is a standard on electronic products, including VCRs, cable and satellite boxes, digital video disc players and home audio players. In the year 2000, more than 99 per cent of all TV set and 100 per cent of all VCR and DVD players sold are equipped with remote controls. The average individual these days probably picks up a remote control at least once or twice a day. Basically, a remote control works in the following manner, a button is pressed. This completes a specific connection which produces a morse code line signal specific to that button. The transistor amplifies the signal and sends it to the LED which translates the signal into infrared light. The sensor on the appliance detects the infrared light and reacts appropriately. The remote controls function is to wait for the user to press a key and then translate that into infrared light signals that are received by the receiving appliance. The carrier frequency of such infrared signals is typically around 36 MHz . The aim of this work is to design and construct a remote control for a Induction Motor regulator. The remote control device sends an infra-red beam, which is received by the infra- red sensor on the regulator and the speed of the Induction Motor is increased.

2. Department of Electrical Engineering Page 2 1.2 PROBLEM STATEMENT:- The remote control technology which is basically controlling an object from a distance provides flexible, effective and accident free way of controlling appliances or systems. It is inconvenient having to move around to change the setting of a Induction Motor regulator in accordance to the temperature of the room, hence, the need for a remote control technology. 1.3 OBJECTIVE:- The purpose of this project is to: Design a remote control that is portable in size and a regulator (receiver) that responds only to the infra-red signal transmitted by the remote control. Control the speed of a ceiling Induction Motor in five levels 1.4 SIGNIFICANCE OF STUDY:- This work will enable people to operate their Induction Motors from a distance. For example, when feeling tired or lazy to get up from their couches and also whilst in bed one can easily reach out his/her remote to control or operate the Induction Motor within a specific distance. In other words, it will add more comfort to everyday living, as the inconvenience of having to move around to operate a Induction Motor regulator is removed. It will also help the aged and the disabled to control their Induction Motor without stress. 3. Department of Electrical Engineering Page 3 CHAPTER 2 LITERATURE VIEW 2.1 REMOTE CONTROL SYSTEMS:- A remote control is an electronic device that is used to control an activity, process, or machine from a distance, by radioed instructions or coded signals. The remote control can be contracted to remote or controller. Commonly, remote controls are consumer IR devices used to issue commands from a distance to televisions or other consumer electronics such as stereo systems, DVD players and dimmers. Remote controls for these devices are usually small wireless handheld objects with an array of buttons for adjusting various settings such as television channel, track number, and volume. In fact, for the majority of modern devices with this kind of control, the remote contains all the function controls while the controlled device itself only has a handful of essential primary controls. Most of these remotes communicate to their respective devices via infrared (IR) signals and a few via radio signals. Earlier remote controls in the 1970s used ultrasonic tones. Television IR signals can be mimicked by a universal remote, which is able to emulate the functionality of most major brand television remote controls. One of the earliest examples of remote control was developed in 1898 by Nikola Tesla, and described in his patent, U.S. Patent 613,809, named Method of an Apparatus for Controlling Mechanism of Moving Vehicle or Vehicles. In 1898, he demonstrated a radio-controlled boat to the public during an electrical exhibition at Madison Square Garden. Tesla called his boat a "teleautomaton". 2.2 EXISTING PROJECTS:- 2.2.1 TELEVISION REMOTE CONTROL:- The first remote intended to control a television was developed by Zenith Radio Corporation in 1950. The remote, called "Lazy Bones", was connected to the television by a wire. A wireless remote control, the "Flashmatic", was developed in 1955. It worked by shining a beam of light onto a photoelectric cell, but the cell did not distinguish between light from the remote and light from other sources. The Flashmatic also had to be pointed very precisely at the receiver in order to work . In 1956, Robert Adler developed "Zenith Space Command", a wireless remote. It was 4. Department of Electrical Engineering Page 4 mechanical and used ultrasound to change the channel and volume. When the user pushed a button on the remote control, it clicked and struck a bar, hence the term "clicker". Each bar emitted a different frequency and circuits in the television detected this sound. The invention of the transistor made possible cheaper electronic remotes that contained a piezoelectric crystal that was fed by an oscillating electric current at a frequency near or above the upper threshold of human hearing, though still audible to dogs. The receiver contained a microphone attached to a circuit that was tuned to the same frequency. Some problems with this method were that the receiver could be triggered accidentally by naturally occurring noises, and some people could hear the piercing ultrasonic signals. There was an incident in which a toy xylophone changed the channels on such sets because some of the overtones from the xylophone matched the remote's ultrasonic frequency. The impetus for a more complex type of television remote control came in the late 1970s, with the development of the Ceefax teletext service by the BBC. Most commercial remote controls at that time had a limited number of functions, sometimes as few as three: next channel, previous channel, and volume/off. This type of control did not meet the needs of teletext sets, where pages were identified with three-digit numbers. A remote control to select teletext pages would need buttons for each numeral from zero to nine, as well as other control functions, such as switching from text to picture, and the normal television controls of volume, channel, brightness, color intensity, etc. Early teletext sets used wired remote controls to select pages, but the continuous use of the remote control required for teletext quickly indicated the need for a wireless device. So BBC engineers began talks with one or two television manufacturers, which led to early prototypes in around 19771978 that could control many more functions. ITT was one of the companies and later gave its name to the ITT protocol of infrared communication . In 1980, a Canadian company, View star, Incorporated, was formed by engineer Paul Hrivnak and started producing a cable TV converter with an infrared remote control. The product was sold through Philips for approximately $190 CAD. At the time the most popular remote control was the Sarcoma of Jerrold (a division of General Instruments) which used 40-kHz sound to change channels . 5. Department of Electrical Engineering Page 5 2.2.2 RADIO REMOTE CONTROL:- Radio remote control (RF Remote Control) is a way to control distance objects using a variety of radio signals transmitted by the remote control device. By using radio remote control system, you can control a variety of mechanical or electronic devices to complete various operations, such as closing circuit, move handle, start motor, etc. As a complementary method to infrared remote control type, the radio remote control is widely used in garage door remote control, electric gate remote control, automatic barrier remote control, burglar alarm, industrial remote control and wireless home alarm systems. A radio remote control system commonly has two parts: transmit and receive. Transmitter part is generally divided into two types, namely, RF remote control and transmitter module, by the way of using, the RF remote control can be used independently as a whole while the transmitter module is used as a component in the circuit, the advantage of using transmitter model is it can be seamlessly connected with application circuit, and it's size is small, but users must have a knowledge of circuit to use the transmitter module, the RF remote control is much more easy to use at this point . Receiver part also is generally divided into two types, namely, the super-regenerative receiver and the super heterodyne receiver, super-regenerative receiver is actually working like the regeneration of under intermittent oscillation detection circuit. While super heterodyne type is working like the one in radio receiver. Super heterodyne receiver features stability, high sensitivity and the anti-interference ability is relatively good, while super-regenerative receiver features a small package and the price is also cheaper. 2.2.3 PC REMOTE CONTROL:- Existing infrared remote controls can be used to control PC applications. Any application that supports shortcut keys can be controlled via IR remote controls from other home devices (TV, VCR, AC, ...). This is widely used with multimedia applications for PC based Home Theatre systems. For this to work, you need a device that decodes IR remote control data signals and a PC application that communicates to this device connected to PC. Connection can be made via serial port, USB port or motherboard IrDA connector. Such devices are commercially available or it can be home made using low cost microcontrollers. LIRC (Linux IR Remote control) and Win-LIRC (for Windows) software are developed for the purpose of controlling PC using TV remote and can be also used for homebrew remote with lesser modification. They support almost all TV remotes . 6. Department of Electrical Engineering Page 6 2.3 DESCRIPTION OF PROJECT:- Basically, this project is designed in this manner. When a button on the remote control is pressed, it completes a specific connection which produces a morse code line signal specific to that button. The transistor amplifies the signal and sends it to the LED which translates the signal into infrared light. The sensor on the appliance detects the infrared light and reacts appropriately. The remote controls function is to wait for the user to press a key and then translate that into infrared light signals that are received by the receiving appliance. The carrier frequency of such infrared signals is typically around 38 kHz. Usually, the transmitter part is constructed so that the transmitter oscillator which drives the infrared transmitter LED can be turned on or off by applying a TTL (transistor-transistor logic) voltage on the modulation controlled input. On the receiver side, a photo transistor or photodiode takes up the signals. Here the variation in the firing angle of triac is used for regulating the speed. Any button on the remote can be used for controlling speed of the Induction Motor. Fig 2.1 Transmitter and Receiver circuit 7. Department of Electrical Engineering Page 7 2.4 APPLICATIONS OF THIS PROJECT:- Remote control Induction Motor regulator is used to control the speed of Induction Motor. The same circuit finds its use to control the intensity of light at various levels. This circuit also finds it use for switching on and off any electronic circuit. 2.5 ADVANTAGES OF THIS PROJECT:- This circuit is simple to use and efficient. It is small in size. It is cheap and hence very economical. It can be assembled with ease. 8. Department of Electrical Engineering Page 8 CHAPTER 3 METHODOLOGY 3.1 INTRODUCTION:- This chapter presents the list of the various components used in the individual blocks put together to form this project. It also explains the techniques used for the construction of both the regulator and the remote control. The tools and other materials that were used to make the project a reality are listed so as to make it easy for people who might in the future wants to do this project. 3.2 COMPONENTS USED:- The remote control unit was made up of the following components Transmitter Receiver Transistors Capacitors Encoder IC Decoder IC Diode Light Emitting Diode (LED) Regulator IC / Switch Integrated circuit : This was used to for the selection of the speed levels. The resistors, capacitors and the inductor were used for voltage regulation, filtering and smoothing. The LED was used to emit signals to the infrared receiver of the regulator. The crystal was used to set the oscillator frequency of the transmitter section.. The switch was sued to switch on or off the Induction Motor. The transistors were amplification of the signals. 9. Department of Electrical Engineering Page 9 3.3 TOOLS FOR THE PROJECT:- The various tools were employed in the building of this project: (a) Hand Tools Set of screw drivers: These were used to tighten screws of the case and the matrix boards A pair of long nose pliers: This was used to hold and tighten bolt and nut. A side cutter: this was used to cut terminals of passive devices and cables. A wire stripper: this was used to strip the tip of the cables or wires. (b) Instruments Digital Multimeter The digital multimeter was used to measure the voltage, current, and resistance of components An oscilloscope was used to observe the voltage and current waveforms and measured the frequency of the electrical signals of the various circuits. (c) Soldering iron and Lead Soldering was done by usage of the soldering iron and the lead. The soldering iron was used to the pieces of copper wires to each other and to the terminals. A coil of lead with flux was required for the soldering. The flux prevented dry joints in the soldering process. The joining surfaces were cleansed to remove grease and dirt in order for the joint to bond properly. 3.4 CONSTRUCTION:- 3.4.1 CONSTRUCTION OF THE REMOTE CONTROL:- The PCB (Printed Circuit Board) was used. The key pad is regularly used so it was taken into account during the designing of the circuit. The PCB was cut in a way that can be handled by everyone. The links or wires were cut in a way that the copper linked the required component. Each of the components was soldered to the copper conductors on the PCB. The remote control is powered by batteries. The total VCC of the remote control was only 3V. All the components have very little current running through them and they all share the 3V supply. 10. Department of Electrical Engineering Page 10 3.4.2TESTING:- After the construction some test was carried out and these there are discussed below. 3.4.3 TESTING FOR POWER SUPPLY:- Every component was checked for short circuit through multimeter. Power supply is given & the output of the various components is tested Output of the transformer -12.02 volt A.C 3.4.4 TESTING FOR RECEIVER CIRCUIT:- Receiving circuit was tested by using a multimeter. We tested all the pins when load was connected. When the RF transmitter transmitted 434MHz frequency Output voltage at the receiver: 5.5V. Output current at the receiver: 5mA 11. Department of Electrical Engineering Page 11 CHAPTER 4 DESIGNING & WORKING 4.1 SYSTEM DESIGN The figure below represents the block diagram of the remote controlled Induction Motor regulator. REMOTE CONTROL RF RECEIVER DECODER IC DECADE COUNTER PNP TRANSISTOR AC SOURCE TRANSFOR MER REGULAT OR SIGNAL INDUCTION MOTOR (LOAD) RHEOSTATE DC RELAY 12. Department of Electrical Engineering Page 12 The individual units in the block diagram was explained by the aid of the circuit diagrams. These diagrams below are the complete circuit diagrams of the design of the Induction Motor regulator and the remote control systems. 4.2 COMPONENTS USED :- 4.2.1 Resistor (Resistance):- Resistor is an electrical component that reduces the electric current.The resistor's ability to reduce the current is called resistance and is measured in units of ohms (symbol: ). Ohm's law The resistor's current I in amps (A) is equal to the resistor's voltage V in volts (V) divided by the resistance R in ohms (): I = VR The resistor's power consumption P in watts (W) is equal to the resistor's current I in amps (A) times the resistor's voltage V in volts (V): P = I V Resistor Symbol :- 13. Department of Electrical Engineering Page 13 Fig:-4.2 Types of resistor Resistor types Variable resistor Variable resistor has an adjustable resistance (2 terminals) Potentiometer Potentiometer has an adjustable resistance (3 terminals) Photo-resistor Reduces resistance when exposed to light Power resistor Power resistor is used for high power circuits and has large dimensions. Surface mount (SMT/SMD) resistor SMT/SMD resistors have small dimensions. The resistors are surface mounted on the printed circuit board (PCB), this method is fast and requires small board area. Resistor network Resistor network is a chip that contains several resistors with similar or different values. Carbon resistor Chip resistor Metal-oxide 14. Department of Electrical Engineering Page 14 resistor Ceramic resistor Table 4.1 :-Type of Resistor Table:-4.2 About Resistance In this we use 1k, 10k and 100k resistance. These shown below:- 15. Department of Electrical Engineering Page 15 Fig:- 4.2 Layout of Resistances Variable resistance Fig:-4.3 Layout of Variable Resistance Variable resistors are also common components. They have a dial or a knob that allows you to change the resistance. This is very useful for many situations. Volume controls are variable resistors. When you change the volume you are changing the resistance which changes the current. Making the resistance higher will let less current flow so the volume goes down. Making the resistance lower will let more current flow so the volume goes up. The value of a variable resistor is given as its highest resistance value. For example, a 500 ohm variable 16. Department of Electrical Engineering Page 16 resistor can have a resistance of anywhere between 0 ohms and 500 ohms. A variable resistor may also be called a potentiometer. 4.2.2 Capacitor Fig:-4.4 Types of capacitor Now suppose you want to control how the current in your circuit changes (or not changes) over time. Now why would you? Well radio signals require very fast current changes. Robot motors cause current fluctuations in your circuit which you need to control. What do you do when batteries cannot supply current as fast as you circuit drains them? How do you prevent sudden current spikes that could fry your robot circuitry? The solution to this is capacitors. Fig:-4.5 Capacitance Capacitors are like electron storage banks. If your circuit is running low, it will deliver electrons to your circuit. In our water analogy, think of this as a water tank with water always flowing in, but with drainage valves opening and closing. Since capacitors take time to charge, and time to discharge, they can also be used for timing circuits. Timing circuits can be used to generate signals such as PWM or be used to turn on/off motors in solar powered BEAM robots. 17. Department of Electrical Engineering Page 17 Quick note, some capacitors are polarized, meaning current can only flow one direction through them. If a capacitor has a lead that is longer than the other, assume the longer lead must always connect to positive. 4.2.3 Connecting Leads A lead is an electrical connection consisting of a length of wire or metal pad that comes from a device. Leads are used for physical support to transfer power. Fig:-4.5 Connecting Leads 4.2.4 Transformer A transformer is a static electrical device that transfers energy by inductive coupling between its winding circuits. A varying current in the primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic flux through the secondary winding. This varying magnetic flux induces a varying electromotive force (emf) or voltage in the secondary winding. Transformers can be used to vary the relative voltage of circuits or isolate them, or both. 18. Department of Electrical Engineering Page 18 Fig:-4.6 Transformer Transformers range in size from thumbnail-sized used in microphones to units weighing hundreds of tons interconnecting the power grid. A wide range of transformer designs are used in electronic and electric power applications. Transformers are essential for the transmission, distribution, and utilization of electrical energy. Type of Transformer:- Step-Up Transformer Step-Down Transformer Hear we use step-down transformer which step down voltage(230V to 12V) at same frequency(50HZ). 19. Department of Electrical Engineering Page 19 4.2.5 Diodes Fig:-4.7 Diode Diodes are components that allow current to flow in only one direction. They have a positive side (leg) and a negative side. When the voltage on the positive leg is higher than on the negative leg then current flows through the diode (the resistance is very low). When the voltage is lower on the positive leg than on the negative leg then the current does not flow (the resistance is very high). The negative leg of a diode is the one with the line closest to it. It is called the cathode. The positive end is called the anode. Usually when current is flowing through a diode, the voltage on the positive leg is 0.65 volts higher than on the negative leg. 4.2.6 Switches Switches are devices that create a short circuit or an open circuit depending on the position of the switch. For a light switch, ON means short circuit (current flows through the switch, and lights light up.) When the switch is OFF, that means there is an open circuit (no current flows, lights go out. When the switch is ON it looks and acts like a wire. When the switch is OFF there is no connection. 20. Department of Electrical Engineering Page 20 4.2.7 The LED Fig:-4.8 LED An LED is the device shown above. Besides red, they can also be yellow, green and blue. The letters LED stand for Light Emitting Diode. The important thing to remember about diodes (including LEDs) is that current can only flow in one direction. 4.2.8 Transistor Transistors are basic components in all of today's electronics. They are just simple switches that we can use to turn things on and off. Even though they are simple, they are the most important electrical component. For example, transistors are almost the only components used to build a Pentium processor. A single Pentium chip has about 3.5 million transistors. The ones in the Pentium are smaller than the ones we will use but they work the same way. Transistors that we will use in projects look like this: Fig:-4.9 Transistor The transistor has three legs, the Collector (C), Base (B), and Emitter (E). Sometimes they are labeled on the flat side of the transistor. Transistors always have one round side and one flat side. If the round side is facing you, the Collector leg is on the left, the Base leg is in the middle, and the Emitter leg is on the right. 21. Department of Electrical Engineering Page 21 Transistor Symbol The following symbol is used in circuit drawings (schematics) to represent a transistor. Basic Circuit The Base (B) is the On/Off switch for the transistor. If a current is flowing to the Base, there will be a path from the Collector (C) to the Emitter (E) where current can flow (The Switch is On.) If there is no current flowing to the Base, then no current can flow from the Collector to the Emitter. (The Switch is off.) Below is the basic circuit we will use for all of our transistors. Fig:-4.10 Basic Circuit of Transistor 4.2.9 Relays A relay is usually an electromechanical device that is actuated by an electrical current. The current flowing in one circuit causes the opening or closing of another circuit. Relays are like remote control switches and are used in many applications because of their relative simplicity, long life, and proven high reliability. They are used in a wide variety of applications throughout industry, such as in telephone exchanges, digital computers and automation systems. Department of Electrical Engineering Page 21 Transistor Symbol The following symbol is used in circuit drawings (schematics) to represent a transistor. Basic Circuit The Base (B) is the On/Off switch for the transistor. If a current is flowing to the Base, there will be a path from the Collector (C) to the Emitter (E) where current can flow (The Switch is On.) If there is no current flowing to the Base, then no current can flow from the Collector to the Emitter. (The Switch is off.) Below is the basic circuit we will use for all of our transistors. Fig:-4.10 Basic Circuit of Transistor 4.2.9 Relays A relay is usually an electromechanical device that is actuated by an electrical current. The current flowing in one circuit causes the opening or closing of another circuit. Relays are like remote control switches and are used in many applications because of their relative simplicity, long life, and proven high reliability. They are used in a wide variety of applications throughout industry, such as in telephone exchanges, digital computers and automation systems. Department of Electrical Engineering Page 21 Transistor Symbol The following symbol is used in circuit drawings (schematics) to represent a transistor. Basic Circuit The Base (B) is the On/Off switch for the transistor. If a current is flowing to the Base, there will be a path from the Collector (C) to the Emitter (E) where current can flow (The Switch is On.) If there is no current flowing to the Base, then no current can flow from the Collector to the Emitter. (The Switch is off.) Below is the basic circuit we will use for all of our transistors. Fig:-4.10 Basic Circuit of Transistor 4.2.9 Relays A relay is usually an electromechanical device that is actuated by an electrical current. The current flowing in one circuit causes the opening or closing of another circuit. Relays are like remote control switches and are used in many applications because of their relative simplicity, long life, and proven high reliability. They are used in a wide variety of applications throughout industry, such as in telephone exchanges, digital computers and automation systems. 22. Department of Electrical Engineering Page 22 All relays contain a sensing unit, the electric coil, which is powered by AC or DC current. When the applied current or voltage exceeds a threshold value, the coil activates the armature, which operates either to close the open contacts or to open the closed contacts. When a power is supplied to the coil, it generates a magnetic force that actuates the switch mechanism. The magnetic force is, in effect, relaying the action from one circuit to another. The first circuit is called the control circuit; the second is called the load circuit. A relay is usually an electromechanical device that is actuated by an electrical current. The current flowing in one circuit causes the opening or closing of another circuit. Fig. 4.10 Relay 4.2.10 IC- 7805 Voltage regulator IC's are the ICs 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 heatsink. 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 heatsink. If the voltage input is more, then excess electricity is liberated as heat from 7805. 23. Department of Electrical Engineering Page 23 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. For more information on specifications of 7805 Voltage Regulator please refer the data sheet here (IC 7805 Voltage Regulator Data Sheet). Fig 4.11ic 7805 IC 7805 is a series of 78XX voltage regulators. Its 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. 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. 4.2.11 HT12D DECODER Fig4.12:- HT12D DECODER 24. Department of Electrical Engineering Page 24 HT12D IC comes from HolTek Company. HT12D is a decoder integrated circuit that belongs to 212 series of decoders. This series of decoders are mainly used for remote control system applications, like burglar alarm, car door controller, security system etc. It is mainly provided to interface RF and infrared circuits. They are paired with 212 series of encoders. The chosen pair of encoder/decoder should have same number of addresses and data format. In simple terms, HT12D converts the serial input into parallel outputs. It decodes the serial addresses and data received by, say, an RF receiver, into parallel data and sends them to output data pins. 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. HT12D is capable of decoding 12 bits, of which 8 are address bits and 4 are data bits. The data on 4 bit latch type output pins remain unchanged until new is received. Pin Diagram 4.2.12 HT12E ENCODER Fig4.13:- HT12E ENCODER 25. Department of Electrical Engineering Page 25 HT12E is an encoder integrated circuit of 212 series of encoders. They are paired with 212 series of decoders for use in remote control system applications. It is mainly used in interfacing RF and infrared circuits. The chosen pair of encoder/decoder should have same number of addresses and data format. Simply put, HT12E converts the parallel inputs into serial output. It encodes the 12 bit parallel data into serial for transmission through an RF transmitter. These 12 bits are divided into 8 address bits and 4 data bits. HT12E has a transmission enable pin which is active low. When a trigger signal is received on TE pin, the programmed addresses/data are transmitted together with the header bits via an RF or an infrared transmission medium. HT12E begins a 4- word transmission cycle upon receipt of a transmission enable. This cycle is repeated as long as TE is kept low. As soon as TE returns to high, the encoder output completes its final cycle and then stops. 4.2.13 RF MODULES (434MHz) fig 4.13 RF MODULE The RF module, as the name suggests, operates at Radio Frequency. The corresponding frequency range varies between 30 kHz & 300 GHz. In this RF system, the digital data is represented as variations in the amplitude of carrier wave. This kind of modulation is known as Amplitude Shift Keying (ASK). Transmission through RF is better than IR (infrared) because of many reasons. Firstly, signals through RF can travel through larger distances making it suitable for long range applications. 26. Department of Electrical Engineering Page 26 Also, while IR mostly operates in line-of- sight mode, RF signals can travel even when there is an obstruction between transmitter & receiver. Next, RF transmission is more strong and reliable than IR transmission. RF communication uses a specific frequency unlike IR signals which are affected by other IR emitting sources. This RF module comprises of an RF Transmitter and an RF Receiver. The transmitter/receiver (Tx/Rx) pair operates at a frequency of 434 MHz. An RF transmitter receives serial data and transmits it wirelessly through RF through its antenna connected at pin4. The transmission occurs at the rate of 1Kbps - 10Kbps.The transmitted data is received by an RF receiver operating at the same frequency as that of the transmitter. The RF module is often used along with a pair of encoder/decoder. The encoder is used for encoding parallel data for transmission feed while reception is decoded by a decoder. HT12E- HT12D, HT640-HT648, etc. are some commonly used encoder/decoder pair ICs. Pin Diagram Receiver Module Transmitter Module fig . 4.14 pin of rf module 27. Department of Electrical Engineering Page 27 4.2.14 Printed circuit boards The use of miniaturization and sub miniaturization in electronic equipment design has been responsible for the introduction of a new technique in inters component wiring and assembly that is popularly known as printed circuit. The printed circuit boards (PCBs) consist of an insulating substrate material with metallic circuitry photo chemically formed upon that substrate. Thus PCB provides sufficient mechanical support and necessary electrical connections for an electronic circuit. Advantages of printed circuit boards: - Circuit characteristics can be maintained without introducing variations inter circuit capacitance. Wave soldering or vapour phase reflow soldering can mechanize component wiring and assembly. Mass production can be achieved at lower cost. The size of component assembly can be reduced with corresponding decrease in weight. Inspection time is reduced as probability of error is eliminated. Types of PCBs: - There are four major types of PCBs: - Single sided PCB: - In this, copper tracks are on one side of the board, and are the simplest form of PCB. These are simplest to manufacture thus have low production cost. Double sided PCB:- In this, copper tracks are provided on both sides of the substrate. To achieve the connections between the boards, hole plating is done, which increase the manufacturing complexity. Multilayered PCB: - In this, two or more pieces of dielectric substrate material with circuitry formed upon them are stacked up and bonded together. Electrically connections are established 28. Department of Electrical Engineering Page 28 from one side to the other and to the layer circuitry by drilled holes, which are subsequently plated through copper. Flexible PCB: - Flexible circuit is basically a highly flexible variant of the conventional rigid printed circuit board theme. PCB Manufacturing Process: - There are a number of different processes, which are used to manufacture a PCB, which is ready for component assembly, from a copper clad base material. These processes are as follows:- Preprocessing: - This consists of initial preparation of a copper clad laminate ready for subsequent processing. Next is to drill tooling holes. Passing a board through rollers performs cleaning operation. Photolithography: - This process for PCBs involves the exposure of a photo resist material to light through a mask. This is used for defining copper track and land patterns. Etching: - The etching process is performed by exposing the surface of the board to an etchant solution which dissolves away the exposed copper areas .The different solutions used are: FeCl, CuCl, etc. Drilling: - Drilling is used to create the component lead holes and through holes in a PCB .The drilling can be done before or after the track areas have been defined. Solder Masking: - It is the process of applying organic coatings selectively to those areas where no solder wettings is needed .The solder mask is applied by screen-printing. Metal Plating: - The plating is done to ensure protection of the copper tracks and establish connection between different layers of multiplayer boards. PCBs are stacked before being taken for final assembly of components .The PCB should retain its solder ability. Bare-Board Testing: - Each board needs to ensure that the required connections exist, that there are no short circuits and holes are properly placed .The testing usually consists of visual inspection and continuity testing 29. Department of Electrical Engineering Page 29 4.3 Working of project This radio frequency (RF) transmission system employs Amplitude Shift Keying (ASK) with transmitter/receiver (Tx/Rx) pair operating at 434 MHz. The transmitter module takes serial input and transmits these signals through RF. The transmitted signals are received by the receiver module placed away from the source of transmission. The system allows one way communication between two nodes, namely, transmission and reception. The RF module has been used in conjunction with a set of four channel encoder/decoder ICs. Here HT12E & HT12D have been used as encoder and decoder respectively. The encoder converts the parallel inputs (from the remote switches) into serial set of signals. These signals are serially transferred through RF to the reception point. The decoder is used after the RF receiver to decode the serial format and retrieve the original signals as outputs. These outputs can be observed on corresponding LEDs. Encoder IC (HT12E) receives parallel data in the form of address bits and control bits. The control signals from remote switches along with 8 address bits constitute a set of 12 parallel signals. The encoder HT12E encodes these parallel signals into serial bits. Transmission is enabled by providing ground to pin14 which is active low. The control signals are given at pins 10-13 of HT12E. The serial data is fed to the RF transmitter through pin17 of HT12E. Transmitter, upon receiving serial data from encoder IC (HT12E), transmits it wirelessly to the RF receiver. The receiver, upon receiving these signals, sends them to the decoder IC (HT12D) through pin2. The serial data is received at the data pin (DIN, pin14) of HT12D. The decoder then retrieves the original parallel format from the received serial data. 30. Department of Electrical Engineering Page 30 When no signal is received at data pin of HT12D, it remains in standby mode and consumes very less current (less than 1A) for a voltage of 5V. When signal is received by receiver, it is given to DIN pin (pin14) of HT12D. On reception of signal, oscillator of HT12D gets activated. IC HT12D then decodes the serial data and checks the address bits three times. If these bits match with the local address pins (pins 1-8) of HT12D, then it puts the data bits on its data pins (pins 10-13) and makes the VT pin high. An LED is connected to VT pin (pin17) of the decoder. This LED works as an indicator to indicate a valid transmission. The corresponding output is thus generated at the data pins of decoder IC. A signal is sent by lowering any or all the pins 10-13 of HT12E and corresponding signal is received at receivers end (at HT12D). Address bits are configured by using the by using the first 8 pins of both encoder and decoder ICs. To send a particular signal, address bits must be same at encoder and decoder ICs. By configuring the address bits properly, a single RF transmitter can also be used to control different RF receivers of same frequency. To summarize, on each transmission, 12 bits of data is transmitted consisting of 8 address bits and 4 data bits. The signal is received at receivers end which is then fed into decoder IC. If address bits get matched, decoder converts it into parallel data and the corresponding data bits get lowered which could be then used to drive the LEDs. The outputs from this system can either be used in negative logic or NOT gates (like 74LS04) can be incorporated at data pins. 31. Department of Electrical Engineering Page 31 CHAPTER 5 CONCLUSION With the knowledge of new techniques in Electronics we are able to make our life more comfortable. One such application of electronics is used in this project. Remote controlled Induction Motor Regulator is one of the applications of electronics to increase the facilities of life. It gives one the ability to control the speed of his/her Induction Motor from a distance within the specification. This project was designed in such a way that, if one loss the original remote control, a TV remote can be used to operate the Induction Motor. The same circuit finds its use in many more applications. By this the intensity of light can be controlled using a remote. The intensity of light can be controlled in five levels from off position to maximum intensity possible. So it finds it use as a night lamp by keeping the intensity of lamp in low level. The circuit also finds its use for switching ON and OFF any electronic circuitry. So it is very useful or a real help to old age and physically challenged people, since they can control the speed from the place where they are sitting. I hope this project serves something good in our homes. 32. Department of Electrical Engineering Page 32 REFERENCES 1. Celadon Company File: remote control systems, celadon Inc. 1990. 2. Roland, Ferguson, Five Decades Of Channel Surfing: History Of The TV Remote Control, Archived from the original. 2008. Available [online] http://web.archive.org/web/20080116212531/http://www.zenith.com/subabout/remote a. .html. 3. SB-Projects: RF Remote Control; ITT Protocol, Available [online] a. http://www.sbprojects.com/knowledge/rf/itt.httml 4. Thomasen, Jeff, RF Remote Control Systems, 2nd Edition, Random House, NewYork, pp.13-17, 2001 5. Glenn, IR remote controls, 2008, Available [online] http://www.faculty.iu-bremen.de/birk/lectures/PC101- 2003/17bluetooth/bluetooth/rf.html . 6. https://www.facebook.com/himaanshuderwal 7. http://about.me/himanshuderwal 8. http://himaanshuderwal.blogspot.in 9. http://www.slideshare.net/himaanshuderwal 10. https://plus.google.com/u/0/+HimanshuDerwal 11. http://in.linkedin.com/pub/himanshu-derwal/55/6b6/5b4 Contact me at :- himanshuderwal@gmail.com himanshuderwal@mail.com +919462815770