A PROJECT REPORT

On“AUTOMATIC STREET LIGHT”

Submitted toCharotar University of Science & Technology (CHARUSAT)

For Partial Fulfillment Towards the Award of Degree of

Bachelor of TechnologyElectronics and Communication Engineering

Submitted by

DHWANIT JUNEJA & MEET KANJARIYA

1

INDEX

INTRODUCTION 7

1. AUTOMATIC STREET LIGHT1.1 BLOCK DIAGRAM 81.2 CIRCUIT DIAGRAM 9

2. HARDWARE IMPLEMENTATION2.1 RESISTORS

(a) 330KΩ RESISTOR 10(b) 100KΩ RESISTOR 11

3.2 LIGHT EMMITING DIODE (LED) 12

3.3 LIGHT DEPENDENT RESISTOR(LDR) 13

3.4 TRANSISTOR 14

3.5 POWER SUPPLY 15

4. CIRCUIT ANALYSIS

4.1 CIRCUIT ON GPB 16

5. APPLICATION, ADVANTAGES AND DISADVANTAGES

5.1 APPLICATION 17

5.2 ADVANTAGES 17

5.3 DISADVANTAGES 17

6. CONCLUSION AND SCOPE

6.1 CONCLUSION 18

6.2 SCOPE 18

7. REFRENCES 19

2

LIST OF FIGURES

2.1 BLOCK DIAGRAM 8

2.2 CIRCUIT DIAGRAM 9

3.1(a) 330R RESISTOR 10

3.1(b) 100K RESISTOR 11

3.2 LED 12

3.3 LDR 13

3.4 TRANSISTOR 14

3.5 BATTERY 15

4.1 ON CONDITION 16

4.2 OFF CONDITION 16

3

C H A P T E R 1

INTRODUCTION

1.1 INTRODUCTION

There has been lot of problems in street lights. Major problem in some places is every evening a person has to come and switch ON the street light and it should be again switched OFF in morning. Yes, this may not be the situation in everywhere but exists in many places.

Here is our new simple Electrical/Electronics project about Automatic Street Light Control System. It is a simple and powerful concept, which uses transistor (BC 547 NPN) as a switch to switch ON and OFF the street light system automatically. It automatically switches ON lights when the sunlight goes below the visible region of our eyes. (e.g. in evening after Sunset). It automatically switches OFF lights when Sunlight fall on it ( i.e. on LDR ) e.g. in morning, by using a sensor called LDR (Light Dependent Resistor) which senses the light just like our eyes.

By using this system energy consumption is also reduced because now a days the manually operated street lights are not switched OFF properly even the sunlight comes and also not switched on earlier before sunset. In sunny and rainy days, ON time and OFF time differ significantly which is one of the major disadvantages of using timer circuits or manual operations.

The project exploits the working of a transistor in saturation and cut-off region to switch ON and OFF the lights at appropriate time with the help of an electromagnetically operated switch.

Automatic Street Light needs no manual operation of switching ON and OFF. The system itself detects whether there is need for light or not. When darkness rises to a certain value then automatically street light is switched ON and when there is other source of light, the street light gets OFF. [4]

4

C H A P T E R 2

AUTOMATIC STREET LIGHT

2.1 BLOCK DIAGRAM

Fig.2.1 BLOCK DIAGRAM

- POWER SUPPLY: Here the DC 9V power supply is provided to the circuit components for the automatic switching action of streetlight.

-LDR(Light Dependent Resistor(LDR): It senses the illumination level and gives input to the transistor as a voltage drop.

-SWITCH: Here in this circuit the transistor works as a switch to switch ON and OFF the LED. It works on the principle of resistance and voltage drop across it.

-STREET LIGHT: When the LDR senses the darkness under its visible range the transistor automatically switch ON the LED and the street light glows automatically without any manual operation.

5

2.2 CIRCUIT DIAGRAM

Fig. 2.2 CIRCUIT DIAGRAM

Here in the circuit we have introduced a LDR which will work to sense the light which is the major component of this project. Two resistors of 100k and 330r and one transistor NPN BC 547 is also included in this circuit. A LED is connected between the resistor and collector pin. The Base is connected at one of transistor and LDR. The other resistor is connected with the +ve terminal of power supply and collector. One end of LDR and Emitter is connected with the -ve terminal of power supply.[1][2]

6

C H A P T E R 3

HARDWARE IMPLEMENTATION

3.1 RESISTORS

Resistor is a passive component used to control current in a circuit. Its resistance is given by the ratio of voltage applied across its terminals to the current passing through it. Thus a particular value of resistor, for fixed voltage, limits the current through it. They are present in electronic circuits.

(a) 330kΩ resistor

A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. Resistors act to reduce current flow, and, at the same time, act to lower voltage levels within circuits. In electronic circuits, resistors are used to limit current flow, to adjust signal levels, bias active elements, and terminate transmission lines among other uses. High-power resistors that can dissipate many watts of electrical power as heat may be used as part of motor controls, in power distribution systems, or as test loads for generators. Fixed resistors have resistances that only change slightly with temperature, time or operating voltage. Variable resistors can be used to adjust circuit elements (such as a volume control or a lamp dimmer), or as sensing devices for heat, light, humidity, force, or chemical activity.[3]

Fig. 3.1(a) 330R RESISTOR

7

(b) 100kΩ Resistor

Resistors are common elements of electrical networks and electronic circuits and are ubiquitous in electronic equipment. Practical resistors as discrete components can be composed of various compounds and forms. Resistors are also implemented within integrated.

The electrical function of a resistor is specified by its resistance: common commercial resistors are manufactured over a range of more than nine orders of magnitude. The nominal value of the resistance will fall within a manufacturing tolerance.[3]

Fig. 3.1(b) 100k RESISTOR

8

3.2 LED(Light Emmiting Diode)

A light-emitting diode (LED) is a two-lead semiconductor light source. It is a p–n junction diode, which emits light when activated. When a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductor.[3]

Fig.3.2 LED-Types of LED

* Miniature

* Mid-range

* High-power*AC Driven LED

9

3.3 LDR (Light Dependent Resistor)A photo resistor or light-dependent resistor (LDR) or photocell is a light-controlled variable resistor. The resistance of a photo resistor decreases with increasing incident light intensity; in other words, it exhibits photoconductivity. A photo resistor can be applied in light-sensitive detector circuits, and light- and dark-activated switching circuits.

Fig.3.2 LDR

A photoresistor is made of a high resistance semiconductor. In the dark, a photoresistor can have a resistance as high as several mega ohms (MΩ), while in the light, a photoresistor can have a resistance as low as a few hundred ohms. If incident light on a photoresistor exceeds a certain frequency, photons absorbed by the semiconductor give bound electrons enough energy to jump into the conduction band. The resulting free electrons (and their hole partners) conduct electricity, thereby lowering resistance. The resistance range and sensitivity of a photoresistor can substantially differ among dissimilar devices. Moreover, unique photoresistors may react substantially differently to photons within certain wavelength bands.[3]

10

3.4 Transistor (BC 547)

BC547 is an NPN bi-polar junction transistor. A transistor, stands for transfer of resistance, is 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 current gain of 800. Its equivalent transistors are BC548 and BC549.

The transistor terminals require a fixed DC voltage to operate in the desired region of its characteristic 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 commonly 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]

Fig. 3.4 TRANSISTOR (BC 547)

11

3.5 Power Supply (9V Battery)

The nine-volt battery, or 9-volt battery, in its most common form was introduced for the early transistor radios. It has a rectangular prism shape with rounded edges and a polarized snap connector at the top. This type is commonly used in pocket radios, paintball guns, and small electronic devices. They are also used as backup power to keep the time in certain electronic clocks. This format is commonly available in primary carbon-zinc and alkaline chemistry, in primary lithium iron disulfide, and in rechargeable form in nickel-cadmium, nickel-metal hydride and lithium-ion. Mercury oxide batteries in this form have not been manufactured in many years due to their mercury content. This type is designated NEDA 1604, IEC 6F22 and "Ever Ready" type PP3 (zinc-carbon) or MN1604 6LR61 (alkaline).

Most nine-volt alkaline batteries are constructed of six individual 1.5V LR61 cells enclosed in a wrapper. These cells are slightly smaller than LR8D425 AAAA cells and can be used in their place for some devices, even though they are 3.5 mm shorter. Carbon-zinc types are made with six flat cells in a stack, enclosed in a moisture-resistant wrapper to prevent drying.[3]

Fig.3.5 BATTERY

12

C H A P T E R 4

CIRCUIT ANALYSIS

4.1 Circuit on GPB

Fig. 4.1 ON CONDITION Fig. 4.2 OFF CONDITION

Here in this project the working model of Automatic Street Light on GPB is shown in above figures.

It is a simple and powerful concept, which uses transistor (BC 547 NPN) as a switch to switch ON and OFF the street light system automatically. It automatically switches ON lights when the sunlight goes below the visible region of our eyes. (e.g. in evening after Sunset).The ON condition of this project is shown in fig. 4.1.It automatically switches OFF lights when Sunlight fall on it ( i.e. on LDR ) e.g. in morning, by using a sensor called LDR (Light Dependent Resistor) which senses the light just like our eyes. The OFF condition is shown in fig 4.2 by using the flashlight of a mobile so that the LDR can sense the light and LED switches OFF.

13

C H A P T E R 5

APPLICATION, ADVANTAGES AND DISADVANTAGES

5.1 Application

-We can use it outside of house, corridors or industry area, which helps to save power.

-It can be used as a street light.

-In sea off-shore side we can use it as a dangerous sign.[7]

5.2 Advantages

-Highly sensitive-Works according to the light intensity-Fit and Forget system-Low cost and reliable circuit-By using this Automatic system for street light controlling, we can reduce energy consumption because the manually operated street lights are not switched off properly even the sunlight comes and also not switched on earlier before sunset.[5]

5.3 Disadvantages

-It is sensitive to ambient light and requires careful shielding.

-Can be more complicated to align detector pairs.[3]

14

C H A P T E R 6

CONCLUSION AND SCOPE

6.1 Conclusion

In this project we have studied and implemented the complete working model of an automatic street light using LDR and transistor. This project includes the study of energy saving system in many applications and thus it can be made more efficient and powerful by using a very sensitive LDR. Automatic work can be very useful in the future rather than implementing a manual work for switching action.

6.2 Scope

By using the mechanism of automatic street light we can easily save the AC power supply because a small LED can save a more amount of energy and will give equal brightness same as the brightness given the LED and tube lights working on a high AC supply. It will also decrease the human interference for the daily switching manual action which will save time and money. More efficient and sensitive LDR in future will be helpful for sensing the darkness and light for the working of automatic street light. It will be easily affordable and will be available in the market in upcoming years for the betterment and as a energy saving device.

15

C H A P T E R 7

REFRENCES

1. http://projectabstracts.com/1644/automatic-street-light-control-system.html2. http://circuiteasy.com/automatic-street-light/3. http://wikipedia.com 4. http://quora.com5. http://www.answers.com/Q/What_are_the_advantages_of_automatic_street_light6. http://www.slideshare.net/anish123_jmt/review-14131300

16