Design And Construction Of Radio Frequency (RF) Remote Light Controller

ABSTRACT

This project work deals on the design and construction of an Rf based remote control for an electronic/electrical device say electric lamp with the aim of switching on/off of the lamp at discretion and from a distance. It also eliminates the inconveniences associated with manual switching of bed lamps.  This electronic system is designed in two functional units; the transmitter and the receiver using radio frequency (RF) communication wave band.  The transmitter is a hand-held remote control while the receiver consists of a tuned radio frequency receiver, clock generator, delay circuit, flip-flop and a driver circuitry and electromagnetic relay which actuate the load (lamp).  When the remote control button is pressed, the lamp comes ON and remains ON until the remote is pressed again – it goes OFF.  Many advantages are accredited to this design in terms of robust, durability, cost effectiveness and components availability.  The result being the simple design of a system easy to operate and maintain. A miniaturized design of it will be a reliable, robust and rugged consumer electronics that will sell like a German burger.

CHAPTER ONE

1.1                                           INTRODUCTION

Electronic communication has gained a holistic approach in the world technological growth.  Apparently, no modern electronic system is capable of fascinating the society without an aspect of telecommunication. This trend is so progressive that most remote control systems are designed with RF.

Remote controls devices are devices that sends digitally-coded pulses to control functions like power, volume, tuning, temperature set point, fan speed, just to name a few, to control different equipments. These devices are usually small wireless handheld objects with an array for various adjustable setting buttons for television channel, track number, and volume. For many devices, the remote control contains all the function controls while the controlled device itself has only a handful of essential primary controls. The earlier remote controls used ultrasonic tones [1]. Remote control has continually evolved and advanced over recent years to include Infrared (IR), Radio frequency, Bluetooth connectivity, motion sensor-enabled capabilities, voice control. IR remote control has been proved to be the most popular equipment for office application, for example, control of air conditioner, turn on or switch off light as well as the normal use of satellite receivers and Televisions [2]. In this paper, while implementing the use of various technologies incorporating security, a remote control system which uses the radio frequency technology is developed.

1.2                                         BACKGROUND OF THE PROJECT

Most homes make use of many electrical and electronics appliances such as the television set, standing fan, ceiling fan, air conditioner, lighting bulbs, video players, radio, etc. All these appliances require switching to turn on and turn off these appliances traditionally. This manual switching of any home appliance is an inconvenient method for physically disabled or elderly or even for the young and busy individuals when frequent switching operation is required. Thus, an easier method of switching is developed to replace this manual switching method, using an advanced switching method for electronic home appliances.

The early wired remotes made possible for users to control appliances at a distance, but the wired remote also limited the user’s mobility by either tethering or tripping the users. If the user ran the remote control’s cord under the rugs and furniture, effectively anchoring the device to one location in the room, the remote thereby limits the freedom of movement for which it was designed to provide. But if the cord is left out in the open, the users might stumble over it. The wireless remote control solved all these challenges of the wired remote control and effectively takes control of the household. The use of remote to restore order to the household [3], changes life style; brings multi-function and multi-platform lives easy.

Various technologies have evolved in the past: controlled by radio waves; used to execute commands transmitted by electromagnetic waves; and also the use of battery-operated low- frequency radio transmitter remote control for consumer electronics [4]. The idea for an electronic remote control, which worked wirelessly by shining a beam of light onto a photoelectric cell, came up in the United State in 1955 [3, 4]. Advancement in remote control kept going till recent days where many technologies such as infrared, radio frequency, Bluetooth, Global System for Mobile (GSM) communications control are used for remote control.

The major technology used in home remote controls is infrared (IR) light [2]. The signal between a remote control handset and the device that it controls consists of pulses of infrared light, which is invisible to the human eye, but can be seen through a digital camera, video camera or a phone camera. The transmitter in the remote control handset sends out a stream of pulses of infrared light when the user presses a button on the handset. A transmitter is often a light emitting diode (LED) which is built into the pointing end of the remote control handset. The infrared light pulses form a pattern unique to that button. The receiver in the device recognizes the pattern and causes the device to respond accordingly. Radio Frequency (RF) remote control is used to control distant objects using a variety of radio signals transmitted by the remote control device. As a complementary method to infrared remote controls, the radio remote control was used with electric garage door or gate openers, automatic barrier systems, burglar alarms (for security and also for restriction of the use of household appliances) and industrial automation systems [3]. The importance and benefit of remote control for household applications using radio frequency technology varies:

• It is not affected by line of
• It penetrates most solids materials and passes through walls.
• It transmits signals to longer range, more than that of infrared technology.
• It is not sensitive to light, to weather or any environmental

This paper is confined to the use of Radio Frequency (RF) technology in switching to control household appliances which involves:

• The design and construction of a transmitter circuit that switches to send signal to the receiver circuit using the RF
• The design and construction of a receiver circuit that receives signal from the transmitter circuit via RF technology then acts to switch on or off a household appliance.

1.3                            PROJECT MOTIVATION

The above-mentioned development motivated me to embark on a project research work on the design and construction of an Rf based remote control electric lamp.  This electronic system is designed with a handheld remote control realized using frequency generator and modulator coupled into a tuned class-C amplifier.  The amplified signal is radiated into the atmosphere through a tank circuit at a particular frequency. The receiver is realized with a tuned radio frequency (TRF) receiver coupled into a transistor static switch.  These solid state switches are used to clock a D-type flip-flop through a delay circuit. The output of the flip-flop biases a driver circuitry realized using a Darlington pair transistors which drives the relay to switch ON/OFF the lamp connected to its normally open contact, whenever the remote is pressed.

1.4                        AIM OF THE PROJECT

One of the objectives of this project is to design and implement an Rf based remote control for electric lamp capable of switching ON/OFF of electric lamp from a maximum distance of 200m at convenience.

1.5                            OBJECTIVES OF THE PROJECT

Objectives of this work are:

1. To expose the graduating student to electronic system design using radio frequency (rf).
2. It also familiarize the young engineers with digital system design involving telecommunication systems.

• Another objective of this project is to ground the young engineers in engineering design which is indispensable in engineering professional practice.
  •  SIGNIFICANCE OF THE PROJECT

This project work signifies a lot in telecom, computer and electronic engineering. It is very useful in a number of domestic places like in bedroom and security lamps in the compound. A project of this type if modified can be used as a gate/door opening system, car immobilizer and for industrial process control.  Another vital significance of this system is in the control of Air conditioner and refrigerators and other lamps in modern buildings. This system can be used to start and stop a power generating set from a distance.

IR Transmitter and Receiver pair form a simple circuit which can be easily built.

• APPLICATION OF THE PROJECT

1. Can be used for simple remote controlling applications, small data transfer, etc.
2. IR Transmitter and Receiver pair as a module can be used in security applications, proximity sensors, distance measurement applications, etc.
   • PROBLEM OF THE PROJECT
3. IR Transmitter and Receiver require line of sight communication i.e. they need to be facing each other.
4. The range of IR communication is less and is reliable for short range and small amounts of data.

1.9                                 SCOPE OF THE PROJECT

This project work covers the following: tuned radio frequency transmitter and receiver, flip-flops, Darlington pair transistors and delay circuits.  It also lays great emphasis on passive and active components used to implement the system.

1.10                                       METHODOLOGY

To achieve the aim and objectives of this work, the following are the steps involved:

1. Study of the previous work on the project so as to improve it efficiency.
2. Draw a block diagram.

• Test for continuity of components and devices,

1. Design of the device was carried out.
2. Studying of various component used in circuit.
3. Construction of the circuit was carried out. The construction of this project includes the placing of components on Vero boards, soldering and connection of components,

• Finally, the whole device was cased and final test was carried out.

1.11                      PROJECT ORGANIZATION

This project is presented in six chapters to appropriately illustrate the steps involved in its implementation. Chapter one introduce the design overview, objective and significance of the project. Chapter two is basically the literature review and some theories relevant to the design. Chapter three is the methodology and analysis. Chapter four is on the system design analysis while chapter five elaborates on the implementation, testing and results. Finally chapter six summarizes the entire thesis and recommendations.