A project report onRF Based Door Opener

Submitted for partial fulfillment for the award ofBachelor Of Engineering

Degree inElectrical and Electronics

ByAshish Singla(287009)Ashok Kumar(287010)

Sonia Pal(207019)Tahir Saifi(207020)

Faculty of Engineering and Technology(Formerly Career Institute Of Technology and Management)

Faridabad, HaryanaMay 2012

CERTIFICATE

Certificate that Ashish Singla, Ashok Kumar, Sonia Pal, Tahir Saifi has carried out the

project work presented in this report titled RF BASED DOOR OPENER for the award of

Bachelors of Technology in Electrical and Electronics from the Faculty of Engineering and

Technology (Formerly Career Institute of Technology and Mangement) Faridabad under

my supervision. The report embodies result of original work and studies carried out by

student themselves and content of reports does not form the basis of award of any other

degree to the candidate or to anybody else.

Mr. Anurag Gautam Dr. Leena GProject Guide Head of Department

Electrical & Electronics

ACKNOWLEDGEMENT

It is great opportunity to express my sincere thanks to all who have contributed to do

this seminar through their support, encouragement and guidance.

I express my gratitude and thanks to ANURAG GAUTAM, my project guide

for his constant guidance and help, all through my work.

I thank Deepali Bansal, my course coordinator for his boundless cooperation and

help extended for this seminar.

I also express our gratitude to Leena G, H.O.D - (Electrical and Electronics Department), for providing the necessary facilities for the completion of this seminar work in my college.

And last, but not least huge thanks goes to all the teaching staff of my college and my

friends and my family members for their help in the successful completion of

this seminar.

Table of Contents

i. Acknowledgement

ii. Abstract

1. Chapter 1: Introduction

2. Chapter 2: Material and Methodology

3. Chapter 3: Result and discussion

4. Chapter 4: Future Scope and Application

References

INTRODUCTION

RF module based door System. RF Stands for Radio Frequency. Here we are using this Radio Frequency to open and close the door. An RF Module is a (usually) small electronic circuit used to transmit, receive, or transceive radio waves on one of a number of carrier frequencies. RF Modules are widely used in consumer application such as garage door openers, wireless alarm systems, industrial remote controls, smart sensor applications, and wireless home automation systems. They are often used instead of infrared remote controls as they have the advantage of not requiring line-of-sight operation.

Features of Our Project:

This RF module works on 434 MHz frequency.

Electric Signal is provided by a switch using remote.

Remote contains a Encoder IC

Encoder 12e generates the 434MHz RF frequency.

Receiver section has a circuit includes Decoder.

Decoder receives the 434 MHz frequency signal and give signal to microcontroller.

Programming is done in microcontroller according to requirement which drives the motor driver circuit.

Motor driver circuit open or close the door.

Basic Block Diagram of Project

Detailed Block Diagram :

RF MODULE:

RF Modules are used wireless transfer data. This makes them most suitable for remote control applications, as in where you need to control some machines or robots without getting in touch with them (may be due to various reasons like safety, etc). Now depending upon the type of application, the RF module is chosen. For short range wireless control applications, an ASK RF Transmitter-Receiver Module of frequency 315 MHz or 433 MHz is most suitable. They are quite compact and cheap!

The Transmitter and Receiver are in Pairs Here these worked on 433 MHz frequency(as we selected) .

RF Receiver (Left) and RF Transmitter (Right).

Transmitter:

The transmitter has 4 pins and a diagram is included to show pin function.

The transmitter can be powered by any voltage (Vcc) between 1.5V and 12V. The higher the voltage, the stronger the RF signal becomes. Just make sure not to exceed 12V because if we do the transmitter will break, which is bad. The data that the Microcontroller/Encoder will be sending will go into the pin labeled "Data In". An RF Module is a (usually) small electronic circuit used to transmit, receive, or transceive radio waves on one of a number of carrier frequencies. RF Modules are widely used in consumer application such as garage door openers, wireless alarm systems, industrial remote controls, smart sensor applications, and wireless home automation systems. They are often used instead of infrared remote controls as they have the advantage of not requiring line-of-sight operation.

There are three types of signal modulation methods commonly used in RF transmitter & receiver modules:

ASK FSK OOK

The detailed description, advantages and disadvantages are listed in the linked articles above.

When attaching an external antenna to an RF Module, superior performance can be achieved by selecting an antenna length related to the wavelength of the carrier frequency. For a 315MHz Module, use a 24 cm antenna length, while for a 433.92 MHz, use a 18 cm antenna.

Main factors affecting RF module performance:

As with any other radio-frequency device, the performance of an RF Module will depend on a number of factors. For example, by increasing the transmitter power, a larger communication distance will be achieved. However, this will also result in a higher electrical power drain on the transmitter device, which will cause shorter operating life for battery powered devices. Also, using a higher transmit power will make the system more prone to interference with other RF devices, and may in fact possibly cause the device to become illegal depending on the jurisdiction.

Correspondingly, increasing the receiver sensitivity will also increase the effective communication range, but will also potentially cause malfunction due to interference with other RF devices.

The performance of the overall system may be improved by using matched antennas at each end of the communication link, such as those described earlier.

Finally, the labeled remote distance of any particular system is normally measured in an open-air line of sight configuration without any interference, but often there will be obstacles such as walls, floors to absorb the radio wave signals, so the effective operational distance will in most practical instances be less than specified.

Typical applications

Vehicle monitoring Remote control Telemetry Small-range wireless network Wireless meter reading Access control systems Wireless home security systems Area paging Industrial data acquisition system Radio tags reading RF contact less smart cards Wireless data terminals Wireless fire protection systems Biological signal acquisition Hydrological and meteorological monitoring Robot remote control Wireless data transmissions Digital video/audio transmission Digital home automation, such as remote light/switch Industrial remote control, telemetry and remote sensing. Alarm systems and wireless transmission for various types of low-rate digital signal. Remote control for various types of household appliances and electronics projects. Many other applications field related to RF wireless controlling Mobile web server for elderly people monitoring

Receiver:

The receiver has 8 pins and the datasheet also provides us with a diagram.

The receiver needs between 4.5V and 5.5V to power it. This means we will be feeding the Vcc pin of the receiver ( the pin that you use to power up the receiver) a regulated 5V supply. The receiver will output any data it receives through Pin 2 , which is labeled "Digital Data Output". Pin 3, labeled "Linear Output/Test" is for testing out the receiver, and we will not be using it at all. It takes the receiver around 30 milliseconds to start up.

Features of Receiver RF Module:-

Low power consumption. Easy for application. On-Chip VCO with integrated PLL using crystal oscillator reference. Integrated IF and data filters. Operation temperature range : -20Ċ- +85Ċ Operation voltage : 5 Volts. Available frequency at : 315/434 MHz

Transmitter Circuit:

Here, we can use four switches S1, S2, S3 and S4 to give 4-bit parallel data (D0-D3). Since the switches are in active low state (i.e. low signal is sent when the switch is pressed), we need to add external pull-up resistors as shown, so as to provide a high signal by default. A resistance as high as 1Mohm is required in between OSC1 and OSC2 pins. The Transmitter Enable (TE, pin 14) pin is an active low pin. Thus, it is permanently grounded, so as to enable the transistor always. The output serial data DOUT is fed to the RF Transmitter Module directly.

The most important thing lies in the address pins (A0-A7, pin1-8). Suppose you have two wireless devices (A and B) in your house, both have different remote controls (AA and BB) and both implement the same type of RF module (say 433 MHz). AA is the remote control of A and BB is of B. Now, you obviously wouldn’t want AA to control B (which is the most probable case since both the devices use same kind of RF module, having same frequency!). This is where address pins come into play. There are 8 address pins, thus giving you an opportunity to have 8! (8 factorial) different and independent ways to connect to a device, so that there is no interference. The address pins MUST have the same address in both transmitter and receiver, or else the data won’t be transferred. Refer to the receiver circuit for more details.

We used only 10th pin of the IC which is grounded through a switch S1 which is our main switch.There are four possible switch connections(as shown) to provide Four type of signals to perform the four different operations.Ex:- Left, Right, Forward and Backward.

17th pin(output) of encoder IC is connected to 2nd pin of RF transmitter module. 4th pin of RF transmitter module is connected to antenna to increase the signal

strength.

Receiver Circuit:

MICROCONTROLLER:

A microcontroller (sometimes abbreviated µC, uC or MCU) is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM. Microcontrollers are designed for embedded applications, in contrast to the microprocessors used in personal computers or other general purpose applications.

Microcontrollers are used in automatically controlled products and devices, such as automobile engine control systems, implantable medical devices, remote controls, office machines, appliances, power tools, toys and other embedded systems. By reducing the size and cost compared to a design that uses a separate microprocessor, memory, and input/output devices, microcontrollers make it economical to digitally control even more devices and processes. Mixed signal microcontrollers are common, integrating analog components needed to control non-digital electronic systems.

Some microcontrollers may use four-bit words and operate at clock rate frequencies as low as 4 kHz, for low power consumption (milliwatts or microwatts). They will generally have the ability to retain functionality while waiting for an event such as a button press or other interrupt; power consumption while sleeping (CPU clock and most peripherals off) may be just nanowatts, making many of them well suited for long lasting battery applications. Other microcontrollers may serve performance-critical roles, where they may need to act more like a digital signal processorr (DSP), with higher clock speeds and power consumption.

AT89S52:

Microcontroller is a microprocessor designed specifically for control applications, and is equipped with ROM, RAM and facilities I / O on a single chip.AT89S52 is one of the family MCS-51/52 equipped with an internal 8 Kbyte Flash EPROM (Erasable and Programmable Read Only Memory), which allows memory to be reprogrammed.

Designed by Atmel AT89S52 in accordance with standard instructions and pin layout 80C5.

AT89S52 Microcontroller Features :

• A CPU (Central Processing Unit) 8 Bit.• 256 bytes of RAM (Random Access Memory) internally.• Four-port I / O, which each consist of eight bits• the internal oscillator and timing circuits.• Two timer / counters 16 bits• Five interrupt lines (two fruits and three external interrupt internal interruptions).• A serial port with full duplex UART (Universal Asynchronous Receiver Transmitter).• Able to conduct the process of multiplication, division, and Boolean.• the size of 8 KByte EPROM for program memory.

• Maximum speed execution of instructions per cycle is 0.5 s at 24 MHz clock frequency.If the microcontroller clock frequency used is 12 MHz, the speed is 1 s instruction execution

CPU (Central Processing Unit)This section serves to control the entire operation on the microcontroller.This unit is divided into two parts, the control unit, or CU (Control Unit) and the arithmetic and logic unit or ALU (Aritmetic Logic Unit) The main function control unit is to take instructions from memory (fetch) and then translate the composition of these instructions into a simple collection of work processes (decode), and implement instruction sequence in accordance with the steps that have been determined the program (execute). Arithmetic and logic unit is the part that deals with arithmetic operations like addition, subtraction, and logical data manipulation operations such as AND, OR, and comparison.

Part Input / Output (I / O)This section serves as a communication tool with a single chip device outside the system. Consistent with the name, I / O devices can receive and provide data to / from a single chip.

There are two kinds of devices I / O is used, ie devices for serial connection UART (Universal Asynchronous Receiver Transmitter) and device for so-called parallel relationship with the PIO (Parallel Input Output).Both types of I / O has been available in a single chip AT89S52.

SoftwareSingle flakes MCS-51 family has a special programming language that is not understood by other types of single flakes. This programming language known by the name of the assembler language instruction has 256 devices.However, when this can be done with microcontroller programming using C language.With the C language, microcontroller programming easier, because the C language format will be automatically converted into assembler language with a hex file format.Software on a microcontroller can be divided into five groups as follows:

Data Transfer InstructionsThis instruction serves to move the data, between registers, from memory to memory, from registers to memory, and others.

Arithmetic InstructionThese instructions perform arithmetic operations including addition, subtraction, addition of one (increments), a reduction of one (decrement), multiplication and division.

Logic and Bit Manipulation InstructionsFunctions perform logic operations AND, OR, XOR, comparison, shift and complement data.

Branching instructionsServes to alter the normal sequence of execution of a program. With this instruction, the programs that are implemented will jump to a particular address.

Instruction Stack, I / O and ControlThese instructions set the stack usage, read / write I / O ports, and controlling.

Pin ConfigurationAT89S52 microcontroller has 40 pins with a single 5 Volt power supply. The pin 40 is illustrated as follows:

The function of each pin AT89S52 is:Pin 1 to 8 (Port 1) is an 8-bit parallel port of a two-way (bidirectional) that can be used for different purposes (general purpose).Pin 9 is a pin reset, reset is active if a high ration.

• P3.0 (10): RXD (serial port data receiver)• P3.1 (11): TXD (serial port data sender)• P3.2 (12): INT0 (external interrupt 0 input, active low)• P3.3 (13): INT1 (ekstrernal an interrupt input, active low)• P3.4 (14): T0 (external input timer / counter 0)• P3.5 (15): T1 (external input timer / counter 1)• P3.6 (16): WR (Write, active low) control signal from port 0 write data to memory and input-output data externally.• P3.7 (17): RD (Read, active low) control signal of the reading of input-output data memory external to the port 0. XTAL pin 18 as the second, the output is connected to the crystal oscillator. XTAL pin 19 as the first, high berpenguatan input to the oscillator, connected to the crystal.

Pin 20 as Vss, is connected to 0 or ground on the circuit.

Pin 21 to 28 (Port 2) is 8 bits parallel ports in both directions. This port sends the address byte when accessing external memory is carried on.Pin 29 as the PSEN (Program Store Enable) is the signal used for reading, move the program

the external memory (ROM / EPROM) to microcontroller (active low).Pin 30 as the ALE (Address Latch Enable) to hold down the address for accessing external memory. This pin also functions as a prog (active low) that is activated when the internal program flash memory on the microcontroller (on chip).

Pin 31 as the EA (External Accesss) to select the memory to be used, the internal program memory (EA = Fcc) or external program memory (EA = Vss), also serves as Vpp (programming supply voltage) when programming the internal flash memory on the microcontroller Pin 32 to 39 (Port 0) is an 8-bit parallel port in both directions. Under which functions as a multiplexed address data to access an external program and data memory.Pin 40 as Fcc, connected to +5 V as a ration to the microcontroller.All single chip in the family division of MCS-51 has the address space to programs and data. The separation of program memory and data memory allows data to be accessed by a memory address 8 bits.Even so, the address memory 16 bits of data can be generated through the DPTR register (Point Data Register). Program memory can only be read can not be written because it is stored in the EPROM.In this case the EPROM is available in a single chip AT89S52 for 8 Kbyte

AT89S52 MICROCONTROLLER memory

Memory Program

If EA’s low value, the program will occupy the address 1000 H to FFFF H to external programs.

Data memory

Internal data memory are mapped as shown below memory space is divided into three blocks of the 128 down, 128 up, and space SFR (Special Function Register) Under Section 128 bytes of RAM mapped into the 32 bytes are grouped into four banks and eight registers (R0 to R7). In the next 16 bytes, on the banks of register, form a block of memory space that can teralamati per bit (bit addressable).All bytes that are within 128 below can be accessed either directly or indirectly.Section 128 above can only be accessed by indirect addressing. Section 128 of the RAM is solely in the devices have 256 bytes of RAM.

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The circuit of the receiver is also quite simple. Capacitor C1 is used between Vcc and GND for noise filtering. Apart from that, all the address pins (A0-A7, pin 1-8) are grounded, just as in transmitter. This is to ensure that the transmitted data is being received. Both the transmitter and the receiver MUST have the same address pins configuration. Pin 17 (VT) is enabled whenever the receiver receives any data. The serial data received by the RF Receiver module is directly fed to pin 14 (DIN), which is then converted into 4-bit parallel data (D0-D3). A 33 kohm resistor is connected in between OSC1 and OSC2.

Relay KT-603:

A relay is an electrically operated switch. Many relays use an electromagnet to operate a switching mechanism mechanically, but other operating principles are also used. Relays are used where it is necessary to control a circuit by a low-power signal (with complete electrical isolation between control and controlled circuits), or where several circuits must be controlled by one signal. The first relays were used in long distance telegraph circuits, repeating the signal coming in from one circuit and re-transmitting it to another. Relays were used extensively in telephone exchanges and early computers to perform logical operations.

A type of relay that can handle the high power required to directly control an electric motor or other loads is called a contactor. Solid-state relays control power circuits with no moving parts, instead using a semiconductor device to perform switching. Relays with calibrated operating characteristics and sometimes multiple operating coils are used to protect electrical circuits from overload or faults; in modern electric power systems these functions are performed by digital instruments still called "protective relays".

A simple electromagnetic relay consists of a coil of wire wrapped around a soft iron core an iron yoke which provides a low reluctance path for magnetic flux, a movable iron armature, and one or more sets of contacts (there are two in the relay pictured). The armature is hinged to the yoke and mechanically linked to one or more sets of moving contacts. It is held in place by a spring so that when the relay is de-energized there is an air gap in the magnetic circuit. In this condition, one of the two sets of contacts in the relay pictured is closed, and the other set is open. Other relays may have more or fewer sets of contacts depending on their function. The relay in the picture also has a wire connecting the armature to the yoke. This ensures continuity of the circuit between the moving contacts on the armature, and the circuit track on the printed circuit board (PCB) via the yoke, which is soldered to the PCB.

When an electric current is passed through the coil it generates a magnetic field that activates the armature, and the consequent movement of the movable contact(s) either makes or breaks (depending upon construction) a connection with a fixed contact. If the set of contacts was closed when the relay was de-energized, then the movement opens the contacts and breaks the connection, and vice versa if the contacts were open. When the current to the coil is switched off, the armature is returned by a force, approximately half as strong as the magnetic force, to its relaxed position. Usually this force is provided by a spring, but gravity is also used commonly in industrial motor starters

LED(LIGHT EMITTING DIODE):

A light-emitting diode (LED) is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting. Introduced as a practical electronic component in 1962, early LEDs emitted low-intensity red light, but modern versions are available across the visible, ultraviolet, and infrared wavelengths, with very high brightness.

When a light-emitting diode is forward-biased (switched on), electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence and the color of the light (corresponding to the energy of the photon) is determined by the energy gap of the semiconductor. LEDs are often small in area (less than 1 mm2), and integrated optical components may be used to shape its radiation pattern. LEDs present many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved robustness, smaller size, and faster switching. LEDs powerful enough for room lighting are relatively expensive and require more precise current and heat management than compact fluorescent lamp sources of comparable output.

Light-emitting diodes are used in applications as diverse as aviation lighting automotive lighting, advertising, general lighting, and traffic signals. LEDs have allowed new text, video displays, and sensors to be developed, while their high switching rates are also useful in advanced communications technology. Infrared LEDs are also used in the remote control units of many commercial products including televisions, DVD players, and other domestic appliances

P-N Junction:

A p–n junction is formed at the boundary between a p-type and n-type semiconductor created in a single crystal of semiconductor by doping, for example by ion implantation, diffusion of dopants, or by epitaxy (growing a layer of crystal doped with one type of dopant on top of a layer of crystal doped with another type of dopant). If two separate pieces of material were used, this would introduce a grain boundary between the semiconductors that severely inhibits its utility by scattering the electrons and holes..

P–n junctions are elementary "building blocks" of most semiconductor electronic devices such as diodes, transistors, solar cells, LEDs, and integrated circuits; they are the active sites where the electronic action of the device takes place. For example, a common type of

transistor, the bipolar junction transistor, consists of two p–n junctions in series, in the form n–p–n or p–n–p.

D-C MOTOR :

A DC motor is an electric motor that runs on direct current (DC) electricity. DC motors were used to run machinery, often eliminating the need for a local steam engine or internal combustion engine. DC motors can operate directly from rechargeable batteries, providing the motive power for the first electric vehicles. Today DC motors are still found in applications as small as toys and disk drives, or in large sizes to operate steel rolling mills and paper machines. Modern DC motors are nearly always operated in conjunction with power electronic devices.

Two important performance parameters of DC motors are the motor constants, Kv and Km.

When a current passes through the coil wound around a soft iron core, the side of the positive pole is acted upon by an upwards force, while the other side is acted upon by a downward force. According to Fleming's left hand rule, the forces cause a turning effect on the coil, making it rotate. To make the motor rotate in a constant direction, "direct current" commutators make the current reverse in direction every half a cycle (in a two-pole motor) thus causing the motor to continue to rotate in the same direction.

A problem with the motor shown above is that when the plane of the coil is parallel to the magnetic field—i.e. when the rotor poles are 90 degrees from the stator poles—the torque is zero. In the pictures above, this occurs when the core of the coil is horizontal—the position it is just about to reach in the last picture on the right. The motor would not be able to start in this position. However, once it was started, it would continue to rotate through this position by momentum.

There is a second problem with this simple pole design. At the zero-torque position, both commutator brushes are touching (bridging) both commutator plates, resulting in a short-circuit. The power leads are shorted together through the commutator plates, and the coil is also short-circuited through both brushes (the coil is shorted twice, once through each brush independently). Note that this problem is independent of the non-starting problem above; even if there were a high current in the coil at this position, there would still be zero torque. The problem here is that this short uselessly consumes power without producing any motion (nor even any coil current.) In a low-current battery-powered demonstration this short-circuiting is generally not considered harmful. However, if a two-pole motor were designed to do actual work with several hundred watts of power output, this shorting could result in severe commutator overheating, brush damage, and potential welding of the brushes—if they were metallic—to the commutator. Carbon brushes, which are often used, would not weld. In any case, a short like this is very wasteful, drains batteries rapidly and, at a minimum, requires power supply components to be designed to much higher standards than would be needed just to run the motor without the shorting.

One simple solution is to put a gap between the commutator plates which is wider than the ends of the brushes. This increases the zero-torque range of angular positions but eliminates the shorting problem; if the motor is started spinning by an outside force it will continue spinning. With this modification, it can also be effectively turned off simply by stalling (stopping) it in a position in the zero-torque (i.e. commutator non-contacting) angle range. This design is sometimes seen in homebuilt hobby motors, e.g. for science fairs and such designs can be found in some published science project books. A clear downside of this simple solution is that the motor now coasts through a substantial arc of rotation twice per revolution and the torque is pulsed. This may work for electric fans or to keep a flywheel spinning but there are many applications, even where starting and stopping are not necessary, for which it is completely inadequate, such as driving the capstan of a tape transport, or any instance where to speed up and slow down often and quickly is a requirement. Another disadvantage is that, since the coils have a measure of self inductance, current flowing in them cannot suddenly stop. The current attempts to jump the opening gap between the commutator segment and the brush, causing arcing.

Even for fans and flywheels, the clear weaknesses remaining in this design—especially that it is not self-starting from all positions—make it impractical for working use, especially considering the better alternatives that exist. Unlike the demonstration motor above, DC motors are commonly designed with more than two poles, are able to start from any position, and do not have any position where current can flow without producing electromotive power by passing through some coil. Many common small brushed DC motors used in toys and small consumer appliances, the simplest mass-produced DC motors to be found, have three-pole armatures. The brushes can now bridge two adjacent commutator segments without causing a short circuit. These three-pole armatures also have the advantage that current from the brushes either flows through two coils in series or through just one coil. Starting with the current in an individual coil at half its nominal value (as a result of flowing through two coils in series), it rises to its nominal value and then falls to half this value. The sequence then continues with current in the reverse direction. This results in a closer step-wise approximation to the ideal sinusoidal coil current, producing a more even torque than the

two-pole motor where the current in each coil is closer to a square wave. Since current changes are half those of a comparable two-pole motor, arcing at the brushes is consequently less.

If the shaft of a DC motor is turned by an external force, the motor will act like a generator and produce an Electromotive force (EMF). During normal operation, the spinning of the motor produces a voltage, known as the counter-EMF (CEMF) or back EMF, because it opposes the applied voltage on the motor. The back EMF is the reason that the motor when free-running does not appear to have the same low electrical resistance as the wire contained in its winding. This is the same EMF that is produced when the motor is used as a generator (for example when an electrical load, such as a light bulb, is placed across the terminals of the motor and the motor shaft is driven with an external torque). Therefore, the total voltage drop across a motor consists of the CEMF voltage drop, and the parasitic voltage drop resulting from the internal resistance of the armature's windings.

FUTURE SCOPE AND APPLICATIONS:-

1. Theft Control Security System

2. Easiness for Handicapped in Hospitals, Public places etc.

3. Can be used in Vehicles

4. Wireless Home Security Systems

With the use of Relay we can:-

1. Digital Home Automation, such as remote light/switch

2. Industrial remote control, telemetry and remote sensing.

3. Alarm systems and wireless transmission for various types of low-rate digital signal.

4. Remote control for various types of household appliances and electronics projects.

5. Many other applications field related to RF wireless controlling

REFRENCES

^ http://www.thetechherald.com/articles/Microsoft-brings-TV-voice-control-to-Kinect

^ http://us.playstation.com/ps3/accessories/playstation-move-navigation-controller-ps3.html

^ ICT Roger Crawford - Heinemann IGCSE - Chapter 1 page 16

^ Jonnes, Jill. Empires of Light ISBN 0-375-75884-4. Page 355, referencing O'Neill, John J., Prodigal Genius: The Life of Nikola Tesla (New York: David McKay, 1944), p. 167.

^ "Radio Aims At Remote Control", November 1930, Popular Science

^ "Philco Mystery Control".

^ "Five Decades of Channel Surfing: History of the TV Remote Control". Archived from the original on January 16, 2008. Retrieved December 3, 2008.

^ Farhi, Paul. "The Inventor Who Deserves a Sitting Ovation." Washington Post. February 17, 2007.

^ "SB-Projects: IR remote control: ITT protocol".

^ "Philips tops in converters". The Toronto Star: p. F03. November 29, 1980.

^ Tynan, Dan (October 2, 2006). "The Future of Fun. Coming soon: All the movies, music, and TV you want, when and where you want them". PC World

^ Kaplan, Jeremy (January 11, 2006). "Anywhere, Anytime TV". PC Magazine.

^ Kanellos, Michael (November 8, 2006). "Space-age remote control coming in 2007". Cnet.com.

^ Derene, Glen (2007). "Wii 2.0: Loop remote lets you click by gesture". Popular Mechanics. Retrieved November 11, 2011.

^ Webster, Camilla (November 16, 2007). "Dream Tech Toys". Forbes.com.