AUTOMATIC STREETLIGHT CONTROL USING LDR&IC555 TIMER PROJECT ASSOCIATES V.HARSHA SNIGDHA (13393-EE-249) CH.MUKESH KUMAR (13393-EE-206) S.YUGANDHAR REDDY (13393-EE-239) P.SRI BHANU (13393-EE-234) Under the Esteemed Guidance of MR.B.PRABHAKAR B.TECH,( M.TECH) DEPARTMENT OF DIPLOMA ELECTRICAL & ELECTRONICS ENGINEERING SAI SPURTHI INSTITUTE OF TECHNOLOGY B. GANGARAM, SATHUPALLY-507303, KHAMMAM DIST, T.S. JUNE-2015

CONTENTS Introduction Abstract Working principle Circuit diagram Circuit operation Components used Advantages Disadvantages Applications

INTRODUCTION In these modern days power consumption has been the need of the hour. Because day by day we are utilising most of the natural resources and the time taken to reproduce is much longer. so if we reduce the consumption and the wastage, Even in one field then it will be of a great use. So we can now go for “Automatic street light control”. Street light are helpful in nights all over the world and their usage cannot be ignored. But we observe that these are switched on during daytimes also. Even though when the light is pured these are switched on. so to avoid power wastage we are using automatic street light control. it also used in homely purpose also.

ABSTRACT Automatic street light control can control the street lamp automatically to turn ON or OFF.It adopts photo resistance theory and it has two types; mechanism and electric. It enjoy the advantage of high sensitive, small bulk, big load, adjustable illumination, wide purpose, easy to use and so on. The automatic street light controller comprises a bistable 555timer.There is a LED placed outside for avoiding the street lights. The LDR senses the light and dark variations of day and night. During daylight, the bistable is held in reset condition through LDR.

WORKING PRINCIPLE This circuit uses a popular timer IC555.IC555 is connected as comparator with pin-6 connected with positive rail,the output was high(1).when the trigger pin-2 is at lower then the 1/3rd level of the supply voltage conversely the output goes low(0).when power consumption pin-4,6 & 8 is connected to the positive supply and pin-1 is grounded.To detect the present of an object we have used LDR & a source light. LDR is a special type of resistance whose valve depends upon the brightness of the light which is falling on it. It has resistance of the about one mega ohm.when in total darkness, but a resistance of only about 5kilo ohm.when brightness is illuminated.

Block diagram LDR IC555 LED POWER SUPPLY

CIRCUIT DIAGRAM

CIRCUIT OPERATION When the light falls on the LDR then it resistance decreases which results in increase of the voltage at pin-2 of the IC555.IC555 has got comparator inbuilt, which compares between the input voltage from pin-2 and 1/3rd of the power supply voltage. when input falls below 1/3rd then output is set high otherwise it is set low .Since in brightness ,input voltage at output of pin-3 to drive relay or LED, Besides in poor light condition we get output to energize.

Components used LDR[light dependent resistor] 470ohm resistor LEDS[light emitting diode] Battery 9v Switch 47ohm variable resistor[preset] NE IC555 timer Connecting wires

LDR[light dependent resistor] LDR or Light dependent resistor are very useful especially in light/dark sensor circuits.Normally the resistance of an LDR is very high, sometimes as high as 1000000ohms, but when they are illuminated with light resistance drops dramatically. When the light level is low the resistance of the LDR is high.when the dark light shines onto LDR its resistance falls and current flows through ic555 timer senses and then LED glows.

RESISTOR Resistors are used for regulating current and they resist the

PRESET Preset resistor are used in circuits when it is necessary to alter the resistance. Dark/light and temperature sensors usually have these components as the preset resistor allows the circuit to made more or less sensitivity. A small screw driver can be used to turn the centre part of the

BATTERY For9v battery power supply we can use 6pcs dry cell or 6F22 single piece battery.

SWITCH Any general purpose switch can be used. Switch is used as circuit breaker.

NE IC555 TIMER

LED[light emitting diode] Light-emitting diodes are elements for light signalization in electronics they are manufactured in different shapes,colors and sizes.For their low price,low consumption and simple use they have almost completely pushed aside other light sources-bulbs at first place.They perform similar to common diodes with the difference that they emit light when current flows through them.

Advantages Power consumption is less Circuit cost is less compared the digital circuit Its operation is easy Usage of memory devices like PROM,microprocessor, microcontrollers are not present hence time is less.

Disadvantages Life time is less compared to the digital circuits Power dissipation is high Flexibility is high High sensitivity

Applications It is not only for street lights but also used for homely applications. These are mostly used in 4-way (or) 3-way to avoid accidents.

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