CHAPTER ONE
INTRODUCTION
Light is a luminous and radiant energy. The light from the sun comes to us by radiation. Light as a wave does not require material medium for its propagation and light makes it possible for us to see by producing sensation of vision through our eyes and brain (Akande et al, 2008). Historically the important source of light for humans has been fire, from the ancient lamp fires to the modern kerosene lamps. With the discovery of fire, the earliest form of artificial lighting was used as illuminate in caves, oily animals were also used as lamps after being threaded as wick, fire flies has been used as a lighting source, candles and pottery lamps were also invented (Williams, 2004). Light is an essential item for the life of human beings. The fire is considered as the first source of artificial light created by man. Until then, the working period was limited to sunlight. Since then, man seeks to develop new sources of lighting in order to improve efficiency and quality. At the beginning of the eighteenth century, researches showed the use of electricity for light generation, and in 1879, the first commercial electric lamp was produced. Overtime the electric lighting became ubiquitous in developed countries (James, 2011).With the development of electric light and power systems, electric lighting has effectively replaced fireflies (Robertson, 2002). Electric power has now become the back bone of modern industrial society. Early backup battery systems were huge, dwarfing the size of lights for which the provided power. The system normally used lead acid batteries as storage for full 120volts charge. For comparison, an automobile uses a single lead acid battery as part of ignition system, simple transistors or relay technology was used to switch on lights and battery supply in the event of power failure. Light Emitting Diode (LED) Lanterns are brighter and long lasting than fluorescent lantern because of the small DC (Direct Current) current they consume (Linda, 2002). There are other circuits which feature an impedance matching circuit and rely on stray capacitances between the primary and secondary windings of the transformer (Adegbemile, 2008). Using D.C–A.C converter helps to drive the fluorescent tube but the inherent shortcomings of this method outweighs the advantages (Johannes 1985). A considerable portion of the energy consumed in the electrical system in the world today is converted to artificial lighting.
Light is essential to harmony between the activities of people in the contemporary world. With the increase in the energy consumption by different segments in relation to the difficulty of generation, it is possible to see the importance of efficient ways of lighting. In the late nineteenth century lamps supplied by electricity, based on heating of a carbon or tungsten filament which became incandescent inside a bulb, were developed (Harris, 1993). This kind of lamp still has been used in some applications.
However, due to the low efficiency presented by incandescent lamps and the growing concern about energy saving, new products have been emerging and have become popular (SaJr, 2007). Among them are compact fluorescent lamps, which provide superior performance compared to incandescent lamps. Around the 60’s, the emission of light by recombination of electrons and holes in semiconductors materials was reported and called electroluminescence, emerging the Light Emitting Diode (LED) (Ballough, 2003). This device presents higher luminous efficiency and long useful life compared to the fluorescent lamps (Cervic et al,2005). Currently, the light emitting diode (LED) can be considered the major Challenge in the lighting industry in which technological innovations emerge at every stage. Emergency lighting system is use to maintain the lighting in a possible failure of the normal energy source. It is mandatory in places such as buildings and public areas, ensuring safety, preventing accidents and indicating routes of escape. The traditional models of emergency lighting systems use fluorescent lamps that require batteries with high energy capacity which had considerable weight and size. When light sources with high luminous efficacy and low voltage level are applied in this equipment, the battery used can be reduced and the system becomes compact. Thus, this work develops an emergency lighting system using high-brightness light emitting diodes (LEDs), allowing the use of the emergency lighting system also in the daily activities supplied by mains. Besides, it has the advantage of easy installation of the equipment, with the simple replacement of incandescent and compact fluorescent lamp by LED without any change in the electrical installation.
An Emergency light is then introduced to solve the problem of darkness during power outage and also in the case of urgent exit and emergency. This proposal focuses on the design of a lighting system with the function of automatically switching on when the main power is out and switch off when the main power is on.
Background of the project
The electric light, one of the everyday conveniences that most affects our lives, was not “invented” in the traditional sense in 1879 by Thomas Alva Edison, although he could be said to have created the first commercially practical incandescent light. He was neither the first nor the only person trying to invent an incandescent light bulb. In fact, some historians claim there were over 20 inventors of incandescent lamps prior to Edison’s version. However, Edison is often credited with the invention because his version was able to outstrip the earlier versions because of a combination of three factors an effective incandescent material, a higher vacuum than others were able to achieve and a high resistance that made power distribution from a centralized source economically viable.
In 1802, Humphrey Davy invented the first electric light. He experimented with electricity and invented an electric battery. When he connected wires to his battery and a piece of carbon, the carbon glowed, producing light. His invention was known as the Electric Arc lamp. And while it produced light, it didn’t produce it for long and was much too bright for practical use.
Early battery backup systems were huge, dwarfing the size of the lights for which they provided power. The systems normally used lead acid batteries to store a full 120-volt charge. For comparison, an automobile uses a single lead acid battery as part of the ignition system. Simple transistor or relay technology was used to switch on the lights and battery supply in the event of a power failure. The size of these units, as well as the weight and cost, made them relatively rare installations. As technology developed further, the voltage requirements for lights dropped, and subsequently the size of the batteries was reduced as well. Modern lights are only as large as the bulbs themselves – the battery fits quite well in the base of the fixture.
Statement of problem
It has been noted that due to the challenging state of electricity many people have resorted to applying other means in other to generate electrical power for use and the growing demand for saving electricity is based on the principle of providing light when the power is cutoff. In the actual sense people can be exposed to accident, panicking and it can cause discomfort when people are seriously in great use of electric light and suddenly the light goes off due to power failure, so therefore the emergency lighting system then lights up.
1.3 Aim of the project
The aim of this research work is to construct a lighting system for emergency use. Specifically the system will be in such a way that,
The light turns on automatically when the main power goes out and then switches off on its own when the main power resumes and the system gets charged as soon as the main power resumes.
1.4 Objective of the project
To construct a system that can automatically turn itself ‘on’ and ‘off ‘with the use of BD140 transistor, having a luminous efficiency and uses low voltage with the use of 50mA Light emitting diode.
1.5 Significance of the project
The system is designed and furnished in the way that it add value and beautifies the place where it is situated. This emergency lighting system can equally help in cases of disaster such as the collapsing of building as a result of the occurrence of an earthquake then the light can help for an emergency exit. This research work will help to eliminate the experience and the presence of complete darkness especially at night during power outage which could lead to problem.
This device is:
Battery efficient.
Pollution free
Easy to use
Uses at office, conference room, exhibition hall lighting.
Advantages of the project
This is a simple circuit, durable and long lasting battery.
Power is saved because the circuit switches off the LED based on light conditions.
The project gives room for further modification of the circuit was necessary.
Limitations of the project
A bit delicate circuit.
The luminosity cannot last for 3days
The lux (symbol: lx) is the SI derived unit of luminance and luminous emittance, measuring luminous flux per unit area. It is equal to one lumen per square metre. One lux is equal to one lumen per square metre. Illuminance is a measure of how much Illuminance is a measure of how much luminous flux is spread over a given area (wiki, 2014)
1 lx = 1 lm/m2 = 1 cd•sr/m2.
1.8 Research work organization
The various stages involved in the development of this research work have been properly put into five chapters to enhance concise and comprehensiveness and the concise of reading. This project work is organized sequentially as follows;
Chapter one of this project works is on the introduction of a compact emergency light backup system for power outages. In this chapter, the background of study, statement of problem, aim and objectives, significance, scope of study and the advantages of the project work are discussed.
Chapter two is on the literature review. In this chapter important related topics are reviewed.
Chapter three is on the materials, method used and the testing of the system.
Chapter four is on the results from system.
Chapter five is on the conclusion and recommendation
