User talk:Edilib2022

AUTOMATIC DARK EMERGENCY LAMP invention by Liberty shilling
MARITIME ACADEMY OF NIGERIA, ORON CONSTRUCTION OF AUTOMATIC DARK EMERGENCY LAMP A RESEARCH PROJECT BY CADET. SHILLING LIBERTY INI

SUBMITTED TO SCHOOL OF MARINE ENGINEERING MARITIME ACADEMY OF NIGERIA ORON AKWA IBOM STATE AUGUST 2017

DECLARATION This is to declare that the project work on the construction of automatic dark emergency lam was carried out by: CADET. SHILLING LIBERTY INI

CERTIFICATION We hereby certify that this work, construction of automatic dark emergency lamp is a product of an original research carried out by us. The material used for the project are properly acknowledge in line with the regulations of project writing in maritime academy of Nigeria, Oron Engr. BIMBOLA A SUPERVISOR

Engr. UMOH G. DATE H.O.D ELECTRICAL AND ELECTRONICS DEPARTMENT

DEDICATION This project work is dedicated to the glory of the almighty God, My parent Mr./Mrs. I.j shilling,  and our lecturers Mr. Umontin, Engr. A Bimbola and Dr. Nsikan J, our senior officers cadet. Ebi Ogijor, cadet. H.B Samuel, cadet. Obutewa our friends cadet. E.S Haruna, L.I Sunday and among others, my sponsors, my family and all my well wishers who by one way or the other contributed for the success of this project, may god bless you all.

ACKNOWLEDGEMENT i give our profound gratitude to the giver of life, wisdom and success, God Almighty for protecting us through the period of our stay in the academy. our deep appreciation goes to our biological parents for giving birth to me, financial support, unreserved love and laying a solid foundation for me to obtain my destiny. i love you dearly for being supportive in every stage of my life. Worthy of note is our project supervisor Engr/Mrs. A. Bimbola and my project coordinator Dr. Nsikan James who despite their tight schedule created time to read through, making the necessary corrections and recommendations towards the success of my project. i also like to acknowledge our exceptional lecturer Mr. Umontin, Engr/Mrs. Moniola Fumi, captain. balogun and others for imparting knowledge on me during the pursuit of my national diploma, i thank you all. i extend our sincere gratitude to my friends, colleagues and contemporaries like cadet. E.M Haruna, L.I Sunday, M.C Ikokwu, M.C Elebo, James ikoojo, Effiong E.E and others in maritime academy of nigeria, oron. Finally, Ithank God Almighty for his Guidance, provision and care through our stay in the academy and during the preparatory aspect towards presenting this work.

ABSTRACT Development and technology have resulted in the creation of a wide range of electron gadgets which covers a vast spectrum of application. This report is presenting an idea of Sensor-Controlled Lighting system which will be designed to be the best solution to Save time, money, electricity and the fossil fuel which is producing it. Also, it presents the technical requirements, theoretical concept and the system designing. To add on, results of testing, troubleshooting and the project reflection is included as well.

Automatic dark emergency Lamp is a simple yet, powerful concept, which uses a Light Dependent Resistor (LDR), NE555 integrate circuit and transistor as a switch. By using this system, manual works are 100% removed. It automatically switches ON lights when the sunlight or external light goes below the visible region of our eyes. This is done by a sensor called Light Dependent Resistor (LDR) which senses the light actually like our eyes. It automatically switches OFF lights whenever the sunlight or external light comes visible too your eye. By u sing this system energy consumption is also reduced because nowadays she manually operated room lights are not switched off even the sunlight comes and also switched on earlier before sunset. In this project, no need of manual operation like ON time and OFF time setting. This project clearly demonstrates the working of an NE555 in an astable configuration.

CHAPTER ONE INTRODUCTION The growing demand for the saving of electricity is based on the principle of providing light when the power fails. This is achieved by utilization of rechargeable automatic lamp which gets charged when the main supply is on and stops charging when battery is full. It is automatically illuminated when it senses darkness and automatically off when there is brightness. The LED (light emitting diode) of the lamp automatically lightens up when the main supply fails and the LDR senses darkness. This automatic lamp is mostly used where there is frequent non uniform voltage distribution of power supply. (Haward, 1972) Since power failure is a common phenomenon in Nigeria, the need for an alternative source of illumination in our homes, workshops, offices etc. becomes a viable option. (Isah, 2015). According to (Linda, 2002), Light Emitting Diode (LED) Lanterns are brighter and long lasting than fluorescent lantern because of the small d.c current they consume. Automatic dark emergency lamp is alternative source of illumination which turns on automatically when the supply is off and charges when the main supply is ON. This is mostly used in the villages due to lack of electricity. It is also used in the industries as well as household application where there is frequent non uniform voltage distribution of electricity. There are so many type of emergency lamp of different cost in the market. Emergency lights are standard in new commercial and high occupancy residential buildings such as college dormitories. By the nature of this device, an automatic dark emergency lamp is designed to come ON when the power goes out. Every model therefore requires some sort of a battery or generator system that could provide electricity to the lamps during a blackout. 1.1 Background of Study Automatic dark emergency lamp is a lamp that senses darkness and light in order to power ON/OFF, this project deals with the construction of this type of lamp. the component in the construction of this lamp are variable resistor of 50W, capacitors which is used to filter ripples, the LED, two batteries of 3.7v each connected in parallel, 555ic, NPN transistor. This project is working on three major processes. - It turns on automatically when the main supply fails, so you'll not need to search for it in the dark. - Its battery starts charging as soon as the mains power and stops when the battery is fully charged. - It uses AC power to charge the battery and DC to power the lamp. 1.2 Statement of the Problem In Nigeria, where power supply is epileptic and where power outages have assumed a very high embarrassing dimension, thus causing increased rate of domestic and industrial accidents at night. There is need for automatic source of illumination in our homes, workshops, offices as against the manually operated lamps. 1.3 Aim of the Project The aim of this project is to construct an automatic dark emergency lamp. 1.4 Objectives of the Project - To construct automatic dark emergency lamp that is rechargeable. - To determine the capacity of the battery (LI-ion battery of 3.7v each) - To determine the procedure and steps taken to construct the lamp. 1.5 Significance of the Study The impact of power failure on man daily activities cannot be over emphasized since power plays a very substantial role in a nation. The construction of this automatic emergency lamp will help to reduce the rate of both domestic and industrial accidents at night and in dark places. 1.6 Scope of the Study This project deals with the study and construction of automatic dark emergency lamp that is capable of delivering 60 watts using LDR (Light Dependent Resistor) as light sensor and a rechargeable battery to power it. CHAPTER TWO LITERATURE REVIEW 2.1 Conceptual Framework This chapter is involved with the review of comment and views of prominent scholars and researchers who have dealt with similar construction. Generally, this chapter focuses on the construction parameters, description of comment parts and principle of operation. The earliest models were incandescent light bulbs which could dimly light an area during a blackout and perhaps provide enough light to solve the power problem or evacuate the building. It was quickly realized. However, that a more focused, brighter and longer lasting light was needed. The modern emergency flood light provides a high lumen, wide coverage light that can illuminate an area quite well. Some light are halogen and provide a light source and intensity similar to that of an automatic headlight. (Theraja, 2006) Early battery backup systems were huge, dwarfing the size of the lights for which they provide power. This system normally uses lead acid batteries to store a full 20 voltage charge. For compares, an automobile uses a single lead acid battery as part of the ignition system. Simple relay or transistor technology was used to switch on the light and battery supply in the event of a power failure. The size of those units, as well as the weight and cost, made them relatively rare installations. As technology developed further, the voltage requirements for lights dropped. (Lioyeo, 1970) The earliest lamps were invented by Greek and Roman civilization, where the light was serving the purpose of security. But the technology kept developing and the first electric room lighting employed are clamps, developed by the Russian Pavel Yablochkov in 1875. 2.2 Empirical Studies Taking into concern an automatic street light control system which operates on a 12v DC supply, the automatic street light controller has a photo conductive device whose resistance changes proportional to the extent of illumination, which switches ON and OFF the LED with the use of transistor as a switch. Light dependent resistor a photo conductive device has been used as a transducer to convert light energy into electrical energy. The control dogma of the circuit is that the change in voltage drip across the light dependent resistor on illumination or darkness switches the transistor between cut off region or saturation region and switches OFF or ON the LED. As we know property of LDR that during the time of day resistance is low therefore voltage at the inverting (pin 2) is higher than the voltage at the non-inverting input (pin3) hence the cut off state which means the LED or bulb will not glow. However, when light shines onto the LDR its resistance falls and current flows into the base of the first transistor and then the second transistor. The preset resistor can be turned up or down to increase or decrease resistance, in this way it can make the circuit more or less sensitive. The circuit diagram present here is that of a street light that automatically switches ON when the night falls and turns OFF when the sun rises. Infact, this circuit is implemented in any type of automatic night light. The circuit uses a Light Dependent Resistor (LDR) to sense the light. When there is light the resistance of LDR will be low. So the voltage drop across POT R2 will be high. This keeps the transistor Q1 ON. The collector of Q1 (BC107) is coupled to base of Q2 (SL100). So Q2 will be OFF and so do the relay. The bulb will remain OFF. When night falls, the resistances of LDR will increases to make the voltage across the POT R2 to decrease below 0.6V. This makes transistor Q1 OFF which in turn makes Q2 ON. The relay will be energized and the bulb will glow. CHAPTER THREE MATERIALS AND METHOD OF CONTRUCTION 3.1 Construction of the Automatic Dark Emergency Lamp Construction of the automatic emergency lights consists of different stages, though it has been discussed in the previous chapters. This is about combining and assembling of the different ideas and stages. BLOCK DIAGRAM A.C-D.C CHARGE CONTROL COMPARATOR TRANSISTOR BATTERY SENSOR LED The block diagram above, consist of the following element: 1. A step-down transformer for reducing the high alternating current (A.C) mains voltage to a low A.C voltage, 2. A bridge rectifier for converting alternating current into direct current, a filter capacitor and a voltage regulator. 3. A charge controller, to control the battery when it is fully charge and to cut-off 4. A battery; li-ion battery is the best battery and with that, it is very expensive and sensitive, it has a steady charge and discharge rate. 5. The comparator; this compares the reference resistance and the resistance of the sensor (LDR). 6. The sensor is a light dependent resistor (LDR) which increases in the absence of light up to 5 Mega Ohms. 7. The transistor (NPN) amplify the current to carry the load 8. The LED is the load. 3.2 Power Supply The common source of power supply is the alternating current which is stepped down to direct current to be used by electronics. The alternating current from the national grid is not reliable as they fail when we need them. The common sources of direct current are batteries. They are ripple free and their voltages are low. They are expensive and need to be recharge when they are down and the process of recharging include transformation, rectification, filtration, regulation and control circuits. 3.3 Transformer Transformer is an alternating current machine that is electromagnetic in nature that transfers electrical energy from one circuit to another (electromagnetic induction) without change in frequency. Its input and output current differs in accordance with turn ratio of input and output windings. The physical basic of a transformer is mutual induction between two Circuit which are electrically insulated from each other but magnetically linked with the secondary coil voltage to produce mutually induced EMF (in accordance with faraday’s law of electromagnetic induction Viz, e=md1/dt) Fig 3.1: step down transformer Fig 3.2; A Step down transformer used in this project In this project, a transformer of voltage ratio 220/6vwith500MA is used. Since it operate well as voltage below 240 volt. It also provides isolation from the supply line, hence, an important safety consideration. 3.4 Rectification A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction. The process is known as rectification. The rectifier is a device, which offers a low resistance to current in one direction (i.e. forward direction) and a high resistance in the opposite direction (i.e. reverse direction). A rectifier circuit uses diode (semi- conductor) to convert A.C supply in to D.C supply. Diode are made up of cathode and anode electrodes, and it conducts when the anode is made more positive than the cathode (i.e. forward biased) and does not conduct when cathode is made more positive than the anode. There are forms of rectification circuit using semi-conductor diodes; Half wave rectification only one diode is used. This brings about half cycle the input voltage developed at the output. Full wave rectification, two diodes or four diodes are used (bridge) depending on the nature of transformer used. A full wave rectification is used in this project. Fig 3.3; Half-wave rectifier Fig 3.4; Graetz bridge rectifier: a full-wave rectifier using four diodes. Fig 3.5; Full wave rectifier: using a center tap transformer and two diodes. Considering a full wave bridge rectifier shown on fig5, the analysis shows that during the positive cycle of the input voltages diodes D1 and D3 conduct while on the negative half cycle diode, D2 and D4 conduct. For this project fig 2 is used. 3.5 Filtering The objective of filtering after the rectification process is to minimize and filter the fluctuation (ripples) present in the output voltage Supplied by the rectifier and give a better approximation to a D.C. This is achieved simply by the capacitor to prevent the output voltage from falling to zero as the diodes cutoff. During the positive half cycle of the input voltage, the diode D1 and D3 conduct and their forward current will flow through the load 3.6 Diode A diode is a semi-conductor Device which permits the flow of current in one direction when its anode terminal is made more positive than its cathode terminals. Under this condition, the diode is said to be forward biased when the cathode is more positive than the anode, the diode does not conduct and is said to be reverse biased. It is however used in the rectification process. Fig 3.6: A diode 3.6.1 Applications 1. Diodes are used as power or rectifier diodes, to convert A.C current into D.C current for D.C power supplies. 2. They are used as signal diodes in communication circuit for modulation and demodulation of small signals. 3. They are used in computer in logic circuit. Some diodes for use in voltage tuning circuit as found in radio and television received. 3.7 Zener Diode Zener diode is a particular type of diode that, unlike a normal one, allows current to flow not only from its anode to its cathode, but also in the reverse direction when the so called Zener voltage is reached. Zener diodes have a highly doped p n junction. Fig 3.7: Zener diode 3.7.1 Application 1. Zener diodes are used as voltage regulators. 2. They are used for meter protection. 3. They are 4. Also used as peak clipper. 3.8 Light Emitting Diodes (LED) A light-emitting diode (LED) is a two-lead semiconductor light source that resembles a basic PN junction diode, except that an LED also emits light. Electrons are able to recombine with holes within the device, releasing energy in the form of photons. This effect is called electro luminescence, and the colour of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductor. This is a forward biased P.N junction, which emits visible light when forward biased. Fig 3.8: A light-emitting diode (led) 3.8.1 Application of LEDs They are used in burglary-alarm system. For solid state video display which are rapidly replacing cathode ray tubes. Use for image sensing circuits for picture phones. 3.9 Resistors Resistor is an electrical component that reduces high electric current. The resistor's ability to reduce the current is called resistance and is measured in units of ohms (symbol: Ω). If we make an analogy to water flow through pipes, the resistor is a thin pipe that reduces the water flow. 3.10 Light Sensor The theoretical concept of the light sensor lies behind the LDR (Light Dependent Resistor) which is used in this circuit as a darkness detector. The LDR is a resistor and its resistance varies according to the amount of light falling on its surface. When the LDR detect light its resistance will get decreased, thus if it detects darkness its resistance will increase. Light Dependent Resistors are very useful especially in light/dark sensor circuits. Normally the resistance of an LDR is very high, sometimes as high as 5000000ohms, but when they are illuminated with light resistance drops dramatically. When the light level is low the resistance of the LDR is high. This prevents current from flowing to the base of the transistors. Consequently, the LED does not light. Fig3.9. Image of Light Dependent Resistor 3.11 Printed Circuit Board PCB PCB is a mechanically support and electrically connects electronic components using conductive tracks, pads and other features each from copper sheets laminated onto a non-conductive subtract. The components in the automatic dark emergency lamp are being soldered on the printed circuit board. 3.12 Variable Resistor Variable resistor is an electronic component that is used to vary the amount of current that flows through a circuit. 3.13 555ic (Integrated Circuit) The 555 integrated circuit is a chip used in a variety of timer, pulse, generation and oscillator applications. The 555ic can be used to provide time delays as an oscillator and as a flip flop element. The 555ic has 8 pins. Introduced in 1972 by Signetics, the 555ic is still in wide spread use due to its low price, ease of use, and stability. It is now made by many companies in the original bipolar and in low-power CMOS. As of 2003, it was estimated that one billion units were manufactured every year. The 555 is the most popular integrated circuit ever manufactured. Fig 3.10 555 integrated circuit Fig 3.11 Block Diagram of a 555ic The internal block diagram and schematic of the 555time rare Highlighted with the same color across all three drawings to clarify how the chip is implemented: 3.13.1 Green Between the positive supply voltage VCC and the ground GND is a voltage divider consisting of three identical resistors which create two reference voltages at 1⁄3 VCC and 2⁄3 VCC. The latter is connected to the Control Voltage pin. All three resistors have the same resistance, 5kΩ for bipolar timers, 40kΩ (or other higher resistance values) for CMOS timers. It is a false myth that the 555 IC got its name from these three 5kΩ resistors. 3.13.2 Yellow The comparator negative input is connected to the higher- reference voltage divider of 2⁄3 VCC (and Control pin), and comparator positive input is connected to the "Threshold" pin. 3.13.3 Orange The comparator positive input is connected to the lower- reference voltage divider of 1⁄3VCC, and comparator negative input is connected to the "Trigger" pin. 3.13.4 Purple A SR flip-flop stores the state of the timer and is controlled by the two comparators. The "Reset" in over rides the other two inputs, thus the flip flop (and therefore the entire timer) can be reset at anytime. 3.13.5 Pink The output of the flip-flop is followed by an output stage With push-pull (P.P.) output drivers that can load the "Output" pin With up to 200mA (varies by device). 3.13.6 Cyan Also, the output of the flip-flop turns on a transistor which connects the "Discharge" pin to ground. 3.13.7 Pin 1- (Ground) GND This pin 1 is normally connected to the circuit common when operated from positive supply voltage. 3.13.8 Pin 2- (Trigger) This pin is an input which causes the output to go high and begin the timing cycle. 3.13.9 Pin 3 - (Output) The output pin of the 555ic moves to a high level of 1.7 volts less than the supply voltage when the timing cycle begins. 3.13.10 Pin 4- (Reset) A low logic level on this pin reset the timer and returns the output to a low state. It is normally connected to the positive supply line. if not used . 3.13.11 Pin 5- (Control) This pin allows charging and triggering and threshold voltages by applying an external voltage. 3.13.12 Pin 6- (Threshold) This is used to reset the latch and cause the output to go low. 3.13.13 Pin 7- (Discharge) This pin is an open collector output which is in phase with the main output on pin 3 and has similar current sinking capability. 3.13.14 Pin 8- (VCC) This is the positive supply voltage terminal of the 555 timer integrated circuit. Supply voltage operating range is +4.5 volts (minimum) to +6 volts (maximum). 3.14 Transistors BC547 is an NPN bi-polar junction transistor. A transistor stands for transfer or resistance commonly used to amplify current. A small current at its base controls a larger current at collector & emitter terminals. BC547 is mainly used for amplification and switching purposes. It has a maximum cu rrent gain of 800. It’s an equivalent transistor. The transistor terminals r equire a fixed DC voltage to operate in the desired region of its characteri stic curves. This is known as the biasing. For amplification applications, the transistor is biased such that it is partly on for all input conditions. The input signal at base is amplified and taken at the emitter. BC547 is used in common emitter configuration for amplifiers. The voltage divider is the c ommonly used biasing mode. For switching applications, transistor is biased so that it remains fully on if there is a signal at its base. In the absence of base signal, it gets completely off. 3.15 Capacitor Capacitor in an automatic dark emergency lamp is use to filter ripples. Capacitor is a device used to store an electric charge, consisting of one or more pairs of conductors separated by an insulator. It is a two terminal electrical component. We use 157uf capacitor in the construction of automatic dark emergency lamp. 3.16 3.7v battery This standby battery provides DC input power to the circuit. A battery is essentially a can full of chemicals (either in paste or liquid form) that produces electrons. The battery used in this project is a 3.7v lithium ion battery. Manufactures produce verities of batteries for specific applications of the customer. Some of the applications considered are: 1. Size 2. High energy density 3. Low price 4. Longevity 5. We shall scrutinize the battery base on: 6. Longevity load characteristics, maintenance requirements and operation cost self-discharge. Types of Batteries; Batteries can be categories in terms of materials used to build them. They differ in terms of capacity, cost and area of usage. In this categorization, there four major types; 1. Nickel-Cadmium (Ni-Cd) Battery 2. Nickel – Metal hydride (Ni-Mh) Battery 3. Lead –Acid Battery 4. Lithium-Ion (Li_-Ion) Battery 5. Lithium polymer 3.16.1 Lithium Ion Battery According to analysis lithium ion has the highest gravimetric energy density. Due to this reason they are used in portable device such as phones, laptops, portable lamps, and portable fans. Lithium ion is safe to use and based on these reasons it was chosen for this project work. Li-ion has high energy capacity also the load characteristics is reasonably good and behave similar to NiCd battery in terms of charge and discharge characteristics Advantages of Lithium ion battery 1. High energy density 2. Relatively low self-discharge 3. Low maintenance Disadvantages of Lithium ion Battery 1. Requires protection circuit 2. Subject to aging, even if not in use 3. Moderate discharge current 4. Expensive 3.17 Battery Charger A battery charger is device use to put energy in to a cell or (Rechargeable Battery) by forcing an electric current through it. Battery chargers typically have two tasks accomplish. 1. To restore battery capacity as quickly as possible. 2. To maintain capacity by compensation for self-discharge. A key factor in prolonging the battery life and obtaining optimum performance for its proper charging environment. This is only possible if the charging current and voltage are properly controlled and matched to the battery temperature. The circuit to charge the batteries in a portable product is an important part of any dependent on the type of battery and the charge time. These consist of three stages 1. Slow charge per-charging stage 2. Fast charge-constant current charge 3. Constant voltage charging stage. Slow Charge- when the battery voltage is below 60% its rated voltage is charged with low charging current .This is really used because Li ion battery does not suffer from memory effect. Fast Charge –the battery is charged with a constant current, the control loop will continuously check the battery current buy sensing the voltage at the resistor. This sensed voltage and reference of the error amplifier will produce error signal at the output of the error amplifier. From the circuit will be seen that, in the heart is IC1 op-amp no JRC4558. Which is connected be the compared circuit. Usually the voltage at pin 3 will be equal to 4V with the Zener diode ZD1-4V. While the battery has a voltage charged in full. The output voltage at pin 6 to negative voltage across the Zener diode, go to make the transistor BC337-Q1 and The Relay-RY1 does not work as well. So The AC voltage input to the transformer-T1 will be cut off. The reduction of the battery voltage will be make voltage at pin 2 of IC1 is lower than at pin 3, this makes style voltage at pin 6 of IC1 to positive and if it is higher than3.3V, it will result in the base current of Q1 to biased the Q1 and to trigger the relay, the contact of relay is connected to the ACV to the transformer T1 so has the secondary coil ACV to a bridge circuit BD1 to DCV and across drop at C1-1,000uF for filter signal full wave rectifier form, to the charging battery system again. Until the voltage battery full will makes pin 2 of IC1 is positive when compare with voltage at pin 3, This circuit will cut off the current that charge battery at once, and begin renew charge again when voltage lower than the setup. CHAPTER FOUR ANALYSIS, RESULTS AND DISCUSSION 4.1 Analysis By using this automatic system for room light controlling, we can reduce energy consumption because the manually operated room lights are not switch off properly even the sunlight comes and also not switched on earlier before sunset. Others are low cost, automated operation, low power consumption, very flexible, easy to be manufactured. In sunny and rainy days, emergency time differ notice which is one of the major disadvantages of using timer circuit or manual operation for switching the room light system. The Automatic dark emergency lamp system operates on 4V DC supply. The automatic dark emergency lamp has a photo conductive device whose resistance changes proportional to the extent of illumination, which switches ON or OFF the LED with the use of transistor as a switch. Light dependent resistor, a photo conductive device has been used as the transducer to convert light energy into electrical energy. The central dogma of the circuit is that the change in voltage drop across the light dependent resistor on illumination or darkness switches the transistor between cut-off region or saturation region and switches OFF or ON the LEDs, we know the property of LDR that during the time of day resistance is low therefore voltage at the inverting input (pin2) is higher than the voltage at the non-inverting input (pin6) hence the output at the pin3 is low so the transistor goes into the cutoff state which means LED will not glow. 555ic Timer IC is the main part of the circuit that works as comparator. All the working of this circuit depends on the working of the 555ic timers. In this circuit, pin3 produce output which has just two states high and low. Output goes to high when trigger pin is at a lower level than the 1/3 RD level of the power supply voltage and output goes low when trigger pin2 is at above then 1/3 RD of the power supply voltage. In this circuit pin4, 6 and 8 are connected to the power supply. Here we use LDR to detect the presence of light which is formed a potential divider circuit with the help of 1kΩ resistor. LDR is a special type of resistor whose value depends on the light. Read this article to know How LDR Works. The output of this divider circuit is given to trigger pin of the 555 timer IC. Circuit of a compact and true solid- state Automatic dark emergency Lamp is described here. The circuit can be used to switch on incandescent garden light bulbs at desk and switch off the mat dawn. A 10m men capsulated light dependent resistor (LDR) here works as the twilight detector. The whole circuit can be plastic or aluminum cabinet. For powering the circuit, AC household supply is needed in order to charge t he battery. 4.2 Modes of operation The IC555 has three operating modes: 4.2.1 Astable Mode The 555ic can operate as an electronic oscillator. Uses include LED and lamp flashers, pulse, generation, logic clocks, tone generation, security alarms, pulse position modulation and soon. The 555ic can be used as a simple ADC, converting an analogue value to a pulse length (e.g. selecting a thermistor as timing resistor allows the use of the 555ic in a temperature sensor and the period of the output pulse is determined by the temperature). The use of a microprocessor- based circuit can then convert the pulse period to temperature. 4.2.3 Mono Stable Mode In this mode, the 555 functions as a "one- shot "pulse generator. Applications include timers, missing pulse detection, bounce-free switches, touch switches, frequency divider, capacitance measurement, pulse- width modulation (PWM) and soon. 4.2.4 Bi Stable (Schmitt) Mode The 555 can operate as a flip-flop, if the DIS pin is not connected and no capacitor is used. Uses include bounce-free latched switches. This project makes use of astable configuration of the NE555ic In astable mode, the 555 timer puts out a continuous stream of rectangular pulses having a specified frequency. Resistor R1 is connected between VCC and the discharge pin (pin7) and another resistor (R2) is connected between the discharge pin (pin7), and the trigger (pin2) and threshold (pin6) pins that share a common node. Hence the capacitor is charged through R1 and R2, and discharged only through R2, since pin7 has low impedance to ground during output low intervals of the cycle, therefore discharging the capacitor. In the astable mode, the frequency of the pulse stream depends on the values of R1, R2 and C. Fig 4.0 astable mode, the frequency of the pulse stream 4.3 List of Components S\N PARTS RANG QUANTITY 1 Transformer 220/6v,300mA 1 2 Diode IN4007 4 3 Zener diode 4v 1 4 Capacitor 103pf 1 5 Capacitor 500uf 1 6 IcNE555 1 7 IcJRC4558 1 8 LDR 1 9 Resistor 1k 2 10 Variable resistor 50k 1 11 Transistor NPNBC547 2 12 Transistor D313 1 13 LED 5watt,3v 10 15 Battery 4vli-ion,2.2amp/H 1 16 Printed circuit board 1 CHAPTER FIVE SUMMARY, CONCLUSION AND RECOMMENDATION 5.1 Summary This project present detailed information about the historical advancement of construction and working principle of automatic dark emergency lamp, it also gives a breakdown of sections that makes up the automatic dark emergency lamp with its components and circuit diagram arrangement. This research work gives an insight of the characteristics of electronics component and brief detail on how the system can be improved by making use of some of those components. 5.2 Conclusion The dark lamp controller using LDR based Light intensity, in today’s up growing countries will be more effective in case of cost, man power and security as compare with today's running complicated and complex light controlling systems. Automatic dark emergency Lamp system puts up a very user friendly approach and could increase the power. This paper elaborates the design and construction of automatic dark emergency lamp system circuit. Circuit works properly to turn its light ON/OFF. After designing the circuit which controls the light of the room as illustrated in the previous sections, LDR sensor and the photoelectric sensors are the two main conditions in working the circuit. If the two conditions have been satisfied the circuit will do the desired work according to specific program. Each sensor controls the turning ON or OFF the lighting column. The street lights have been successfully controlled by microcontroller. With commands from the controller the lights will be ON in the places of the movement when it's dark. Furthermore, the drawback of the street light system using timer controller has been overcome, where the system depends on photo electric sensor. Finally, this control circuit can be used in activating other emergency device. 5.3 Recommendation The system is highly recommended to be used by the following sectors; churches, offices, hospitals, shipping companies. Anyone who desire to improve on the production of this project can increase duration this auto dark emergency lamp can limit, this can be achieved by using high rated voltage battery. Nowadays, automatic dark emergency lamp system has spread globally, leaving the ancient lighting system without automation, therefore it is expected that every organization even our homes will embrace the automatic dark emergency lamp.