automatic dusk to dawn

8/13/2019 Automatic Dusk to Dawn

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PROJE T ONAUTOMATIC DUSK TO DAWN STREET LIGHTCONTROL


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WHATS THE

PROJECT??

This project aims at designing andexecuting the advanced development forenergy saving of street lights with lightdepending resistor.

Nowadays, human has become too busyand he is unable to find time even to switchthe lights wherever not necessary.

This can be seen more effectively in thecase of street

lights.

This project gives the best solution forelectrical power wastage.

Also the manual operation of the lightingsystem is completely eliminated.


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OBJECTIVE

The main objective of this project is to design a system where light willremain on only from dusk to dawn.

Varying light intensity falling on an LDR is used as input to a comparator. Itis compared with a fixed value to turn ON the appliances at the falling light

intensity in the evening to switch OFF in the morning light.

As perunit electricity cost is very high these days, so it is advisable tojudiciously use electricity. Places like colleges, housing complexes, highways,industries and parks spread across large area where more light is requiredduring night. This system provides a solution for these places, as dusk to dawnsystem the lights will be automatically on at dusk and switch off at dawn. Thus,

saving energy and money also human intervention is also eliminated.


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OPERATION OF LDR

Here, It shows that when the torch isturned on, the resistance of the LDRfalls, allowing current to pass through~~


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INSIDE LDRA photoresistor or light dependentresistor(LDR) isresistor whose resistance decreases withincreasing incident light intensity; in otherwords, it exhibitsphotoconductivity.

A photoresistor is made of a highresistancesemiconductor.

If lightfalling on the device is of highenough frequency, photonsabsorbed by thesemiconductor give bound electronsenoughenergy to jump into the conductionband. Theresulting free electron (and its holepartner)conduct electricity, thereby lowering resistance.
http://en.wikipedia.org/wiki/Photoconductivityhttp://en.wikipedia.org/wiki/Photoconductivityhttp://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Frequencyhttp://en.wikipedia.org/wiki/Photonhttp://en.wikipedia.org/wiki/Frequencyhttp://en.wikipedia.org/wiki/Photonhttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Conduction_bandhttp://en.wikipedia.org/wiki/Conduction_bandhttp://en.wikipedia.org/wiki/Conduction_bandhttp://en.wikipedia.org/wiki/Conduction_bandhttp://en.wikipedia.org/wiki/Electron_holehttp://en.wikipedia.org/wiki/Conduction_bandhttp://en.wikipedia.org/wiki/Electron_holehttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Electrical_resistancehttp://en.wikipedia.org/wiki/Electron_holehttp://en.wikipedia.org/wiki/Conduction_bandhttp://en.wikipedia.org/wiki/Electronhttp://en.wikipedia.org/wiki/Photonhttp://en.wikipedia.org/wiki/Frequencyhttp://en.wikipedia.org/wiki/Semiconductorhttp://en.wikipedia.org/wiki/Photoconductivity


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POTENTIOMETER A potentiometer is a three terminal

resistor with a sliding contact that formsan adjustable voltage divider.If only twoterminals are used, one end and thewiper, it acts as a variable resistor.

The variable resistance lets us adjust theresistance between two points in acircuit.

A variable resistance is useful when wedon't know in advance what resistorvalue will be required in a circuit


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WHEATSTONE

BRIDGEFor measuring accurately anyresistance Wheatstone Bridge is widelyused. There are two known resistors, onevariable resistor and one unknownresistor connected in bridge form as

shown. By adjusting the variable resistorthe current through the Galvanometer ismade zero. When the current throughthe galvanometer becomes zero, the ratioof two known resistors is exactly equal to

the ratio of adjusted value of variableresistance and the value of unknownresistance. In this way the value ofunknown resistance can easily bemeasured by using a Wheatstone Bridge.


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PLC TRAINER KIT


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PLC TRAINER KITA Programmable Logic Controller, PLC or ProgrammableController is a digital computer usedfor automation of electromechanical processes, such as controlof machinery on factory assembly lines, amusement rides,or light fixtures.

The input and output variables of PLC system are binary innature.

It is easy to make changes in program sequence of events.

PLC Trainer Specifications :

Digital I/p- 18 Digital O/p-12

Analog I/p-02 Analog O/p-01

Input & Output Ratings : Digital- 24V DC, 0.5A/1A

Analog- 0-3.5V


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HOW THE PROJECT

WORKS??

Construction of Wheatstone bridge.

Components used are LDR, Variable Resistor& two fixed resistors.

The nature of LDR is to decrease the

resistance as soon as intensity of light increasesand vice versa.

This property of LDR is used to operate thecircuit inversely.

Now, As intensity of light decreases,resistance decreases and an output voltage of15V obtained.

This output voltage is driven through the PLCand uses the AC Supply Externally to glow thebulbs which are assumed as street lights.


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CONCLUSION

The project AUTOMATIC STREET LIGHTCONTROL SYSTEM WITH LDR has beensuccessfully designed and tested.

Here we are saving lot of power withoutany wastage, by these advancedtechnologies we can design many moresystems which can be done by solar lightsand through these solar lights we have a

vast usage.


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automatic dusk to dawn

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