Automatic Street Light (Using IC555 and L.D.R.)
Year : 2017 – 2018 2018
I would like to thank my School and my Physics Teacher for introducing me to scientific research, giving me a chance to accelerate my research skills and encouraging me to work in the field of Physics. Their expertise along with their vision has been the source of inspiration to me. The present project work would, therefore, would have never been completed without their proper guidance, regular supervision, and constant encouragement.
I would also like to thanks my internal all faculties, Lab Assistant: Lalit Mohan for helping me in doing this project.
Last but not the least I would like to thank my friends and family & Friends for making this research work successful with their constant support.
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This is to certify that
PULKIT GUPTA Of Class
XII – D
Completed investigatory project on
Automatic Street Light For class XII Physics Practical Examination of Central Board of Secondary Education in the academic year 2016 -2017. It is further certified that the project is the individual work of student.
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Teacher’s Signature
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Examiner’s Signature
Sr. No.
TITLE
Page No.
1.
Introduction
1
2.
Theory
2
3.
Parts Used & Circuit Diagram
4
4.
Working
5
6.
Bibliography
6
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This project Automatic Street Light Control System aims at designing and executing the advanced development in embedded systems for energy saving of street lights by using light dependent resistor (LDR).
Nowadays, human has become too busy and he is unable to find time even to switch the lights on or off. This can be seen more effectively in the case of street lights. The present system is like, the street lights will be switched on in the evening before the sun sets and they are switched off the next day morning after there is sufficient light on the roads. But the actual timing for these street lights to be switched on are when there is absolute darkness on the roads. This project gives the best solution for electrical power wastage. Also the manual operation of lighting system is completely eliminated. In our project we are using LDR, which varies according to the amount of light falling on its surface; this gives an indication for us whether it is a day/night time. This project can be configured by using transistors, CMOS ICs and IC 555. Here, we implement this project by using IC 555. The 555 timer IC is an integrated circuit used in a variety of timer, pulse generation, and oscillator applications. Derivative provide up to four timing circuits in one package. Also we are using relay. We are using Light-emitting diodes (LEDs) in this project instead of a bulb. Light-emitting diodes are elements for light signalization in electronics. By using this project as the basic principle we can design centralized intelligent system for the perfect usage of streetlights in any place.
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Theory
LDR or a Photoresistor: A photoresistor or light – dependent resistor (LDR) or photocell is a lightcontrolled variable resistor . The resistance of a photoresistor decreases with increasing incident light intensity; in other words, it exhibits photoconductivity. A photoresistor can be applied in light-sensitive detector circuits, and light- and dark-activated switching circuits. [i n this project – function of the
LD R is to s ens e the sunlig ht or torch lig ht s o that the LE D may g o on or off according ly] .
L.D.E. (Light Emitting Diode): A lightemitting 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. [in
this project – the role of LE D is to function as a s treet lig ht – but we can change this LED with Electronic Relay for fully functional real circuit] . IC 555 (Timer IC): The 555 timer IC is an integrated circuit (chip) used in a variety of timer, pulse generation, and oscillator applications. The 555 can be used to provide time delays, as an oscillator, and as a flip-flop element.
Introduced in 1971 by American company Signetics. It is now made by many companies in the original bipolar and also in low-power CMOS types. [i n this project I us ed this IC to act as a
flip flop s witch & becaus e it is easily available in the mark et / the circuit is easily available on internet and in most project hobby books] . …………….Page:2
Battery (or Dry Cell): A Dry cell is a type of chemical cell, commonly used today, in the form of batteries, for many electrical appliances. It was developed in 1886 by the German scientist Karl Gassner. A common dry cell is the zinc –carbon battery, sometimes called the dry Leclanché cell, with a nominal voltage of 1.5 - 12 volts, the same as the alkaline battery (since both use the same zinc – manganese dioxide combination). (in the project I have used 9volt Dry Cell). [the role of the 9V battery in thi s ci rcuit is to g ive power to the whole circ uit as well as L E D acting as s treet lig ht] . Diode: is a two-terminal electronic component that conducts primarily in one direction; it has low (ideally zero) resistance to the flow of current in one direction, and high (ideally infinite) resistance in the other. A semiconductor diode, the most common type today, is a crystalline piece of semiconductor material with a p –n junction connected to two electrical terminals. Semiconductor diodes were the first semiconductor electronic devices. The first semiconductor diodes, called cat's whisker diodes, developed around 1906, were made of mineral crystals such as galena. Today, most diodes are made of silicon, but other semiconductors such as selenium or germanium are sometimes used. [in this projec t I us ed the Diode – jus t to g ive direction to output pulse from the output terminals ] .
Variable Resistance (Potentiometer): A resistor may have one or more fixed tapping points so that the resistance can be changed by moving the connecting wires to different terminals. A potentiometer is a three-terminal resistor with a continuously adjustable tapping point controlled by rotation of a shaft or knob or by a linear slider. It is called a potentiometer because it can be connected as an adjustable voltage divider to provide a variable potential at the terminal connected to the tapping point. [In this project – the role of ‘Potentiometer’ is to adjust the amount of light on LDR]. Page:3
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Part Name
Quantity
================================================== 1. IC 555 x 1 2. L.D.R. (Light Dependent Resistance) x 1 [Normal Rating – general purpose] 3. Variable Resistance (Potentiometer) x 1 [5-10 Kilo Ohms approx.] 4. PCB (Printed Circuit Board) x 1 (2.5” x 1.5” size approx) 5. Switch (normal on off switch) x 1 6. LED (Light Emitting Diode) x 1 7. Battery (9 Volts) x 1 8. Base Board (5 mm thick Sunboard) x 1 (A4 Size = 8.3 x 11.7”) 9. Wires (Multi Colour ½ Meter or 1 Meter) x 1 Mtr. 10. Nut Bolts or Screw ½ cm or 1 cm height x 2-4 Nos. [or as per availability] Optional. 11. Soldring Wire (1-2 Mtr.) x 1 Mtr. 12. Cable Tie or Fevibond Rubber Adhesive x 1 No. 13. A4 Sticker Sheet (for Base Making) x 1 14. Some Decorative materials (like road x -car, light pillar etc.) ==================================================
Circuit Diagram for Automatic Street Light:
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Working This
circuit uses a popular timer I.C which is 555. Now when I.C 555 is
connected as comparator with pin 6 connected with positive supply, the output goes high-1 when the trigger pin 2 is at lower than 1/3 level of the supply voltage. Conversely the output goes low-0 , when it is above 1/3 level. So small change in the voltage of pin 2 is enough to change the output of pin 3 from 1 to 0 and 0 to 1.
The output has only two states high and low and can not remain in any intermediate stage. It is power by 9V battery for portable use. The circuit is economic in power consumption. Pin 4,6&8 is connected to the positive supply and pin 1 is grounded. To detect the present of light we have used LDR and a source of light. LDR is a special type of resistance whose value depends on the brightness of the light which is falling on it. It has a resistance of about 1 mega ohms when in total darkness, but a resistance of only about 2-5 k ohms when brightly illuminated. It responds to a large part of the light spectrum. The source of light and LDR is so adjusted in the night lamp that light will directly fall on the LDR but when there is no light in the atmosphere and LDR will be under darkness. We have made a potential divider circuit with LDR and 100 K variable resistance connected in series. Voltage is directly proportional to conductance so more voltage we will get by this divider when LDR is getting light and low voltage in darkness. Divided voltage is given to pin 2nd of 555.
Now as soon as LDR gets dark the voltage of the pin 2 drops 1/3 of the supply voltage and pin 3 gets high and LED glows. We can also use two LED at output pin 3, for present LED 1 and for absent LED 2. For this method one LED is connected as forward bias and other is connected as reverse bias to indicate both high and low conditions. To limit the current of LED resistance is used in series.
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Bibliography 1. Wikipedia (www.wikipedia.com) 2. Google (www.google.co.in) 3. Hobby Electronic Circiuts (BPB Publication Delhi). 4. Physics Text Book Class 12 th, (N.C.E.R.T.)
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