Design and Construction of Automatic Emergency Light

Design and Construction of Automatic Emergency Light

Chapter One

Aim/Objective

The major aim of this project is to design and construct an Automatic Emergency Light System that is capable of providing light of adequate or full brightness when there is mains supply outage. This circuit or system is purposely used during emergency situations for some periods of time. It is aimed at providing enough light depending on its capacity, before the mains supply resumes.

CHAPTER TWO

LITERATURE REVIEW

This project has been constructed by the previous students who graduated before us in this discipline. They used components like light emitting diode, regulator IC, resistor, capacitor, transformer, PN junction diode an 4V battery to build the circuit. But their own is not working automatically. When we want to construct our own we added transistor in the circuit design which act as a switch that improve the charging system.

We designed it in such a way that the charger power supply section could charge 6V, 4.5Ah battery when there is main supply and with the capacity of switching itself off automatically when the battery charges fully. The LED’s were properly arranged in parallel in other to emits a brighter light just unlike the previous project. We equally increased the number of LED’s in other to give more brighter full light. Again in the previous work done by other student, we noticed that the duration of the battery was shorter, that is why we increased the battery from previous 4V to 6V in other to increase the duration of the light.

By this working principle of switching off and ON by the charger itself, I can say that the one constructed by our predecessor was Emergency Light, from the idea we got from their work we improve it by constructing an Automatic Emergency Light.

CHAPTER THREE

SYSTEM OPERATION

Block Diagram

Principle of Operation

The system comprises different sections as shown in the block diagram above.

When the AC mains supply comes to the transformer, it is stepped down to 9V, 500mA which is sent to the Bridge rectifier. The rectifier converts the AC to DC which through the charger charges the 6V battery. When AC mains goes off, this 6V battery powers the LED light section.

Below is the circuit diagram and the working principle.

The circuit comprises majorly two sections; charger power supply and LED driver. The charger power supply section built around a 3-terminal adjustable regulator (IC_I) LM317, while the LED driver section is built around transistor BD 140 (T₂). In the charger power supply section, input AC mains is stepped down by transformer to deliver 9V, 500mA to the bridge rectifier, which comprises diodes (IN4007 x 4). Filter capacitor (25V/1000uf) eliminates ripples. Unregulated DC voltage is fed to input pin 3 of IC_I and provides charging current through diode IN4007(DS) and limiting Resistor (160hm) R₁₆. By adjusting preset 2.2K (VR₁), The output voltage can be adjusted to deliver the required charging current.

CHAPTER FOUR

SYSTEM CONSTRUCTION AND PACKAGING

PROTOTYPING

The prototype of this project was carried out using a breadboard. All the required components were gathered and mounted on the board following the guidelines from the circuit diagram. After completion of the prototype, corrections were made, criticism were done and conclusion was made as to which of the components needs replacement before it was finally moved to the vero board for soldering.

Component Mounting

In mounting the components, repair and maintenance services were taken into consideration. The components were mounted in accordance with the circuit diagram to avoid open circuit and short circuiting. Components like Transistors, Ics (integrated circuits), diodes, capacitors etc were mounted with regard to their polarities.

CHAPTER FIVE

SYSTEM TESTING

In this project various tests were carried out on the device to confirm the level of its performance and efficiency. The test that was carried out was voltage testing and continuity testing.

CONTINUITY TESTING

The different sections of the circuit, the power supply unit, oscillator, driver section, output amplifier etc were tested with multimeter to check for continuity.

VOLTAGE TESTING

The power unit was tested with digital multimeter to determine the output voltage. The inverter output voltage was also tested and it gave 230V at a frequency of 50HZ.

CHAPTER SIX

CONCLUSION AND RECOMMENDATION

CONCLUSION

The aim of setting out this project which is the Design and Construction of Automatic emergency light has been achieved. The system is of high fidelity and will function properly when operated with in the limit of safety at normal room temperature and pressure. It is designed to the utmost performance and will completely favourably with any of the imported ones of the same rating. It is therefore safe to use both in our homes, in office to give light when there is power failure.

RECOMMENDATION

Despite the problems and obstacles encountered before completing this project, we considered it necessary to make some recommendations that will be of great benefit; if adopted.

The Automatic emergency light should be well positioned and kept in an environment where there is enough air so as to help protect the system from overheating.

The system should be handled by a person who understand its operation and need to be charged when the voltage level goes down. While using the problem in component identification should be harmonized. This is the marketer should be encouraged to confirm to the British Standard.

REFERENCES

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Chinwetalu, B.N. (2004). Electronics (Concepts, Materials and Devices). Enugu: Zik Chuks Publishers.
Chinwetalu, B.N. (2004). Electronics (Circuit and Systems), Enugu: Zik Chuks Publishers.
Chinwetalu, B.N. (2008). Principle of Electronics. Enugu: Zik Chuks Publishers.
Croissete, D.L. (1968). Transistors. New Delhi: Prentice Hall, Inc.
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Mandal, S.K. (2012). Basic Electrical & Electronic Engineering II. India: Flipkart Publisher.

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