This document summarizes a student seminar presentation on an automatic street light system using an LDR sensor. The system uses an LDR sensor to detect light levels and a transistor to control a relay that switches street lights on when it gets dark. The presentation describes the components of the system including the LDR sensor, resistor, battery and transistor. It provides the circuit diagram and explains how the system works to automatically turn lights on at night to save energy over manual operation. Potential applications are in outdoor and security lighting that can be powered more efficiently.

1. BHILAI INSTITUTE OF TECHNOLOGY DURG
SEMINAR TOPIC :- AUTOMATIC STREET LIGHT USING LDR
-: PRESENTED BY :-
- SUYASH SAHU
- KUNAL SAHU
- MD. SAAD
-: GUIDED BY :-
MR. MAUSAM SHARMA
(Asst. Professor)
DEPARTMENT OF ELECTRICAL AND ELECTRONIC ENGINEERING
BRANCH:- EEE 3RD SEMESTER

2. Content-
 ABSTRACT
 INTRODUCTION
 COMPONENTS
 DESCRIPTION OF EACH COMPONENTS
 CIRCUIT DIAGRAM
 WORKING
 RESULT
 APPLICATION
 ADVANTAGE
 DISADVANTAGE
 CONCLUSION

3. ABSTRACT-
The main purpose of this project is to switch ON
and OFF street light without manual operation.
By using this system energy consumption is
reduced.
IR sensors and micro controller are the main
components of the project.
IR sensor is like our eye which detect the presence
of an object.

4. INTRODUCTION-
Many of people have a phobia of
darkness ,to assist them in such situation , we have
explained a simple circuit. It will automatically turn
on street light in the way of LEDs or bulb coupled
with relay .
Working this circuit it very much easy
and also the power consumed by the circuit is very
low because of the very components used in the
circuit.

5. COMPONENTS:
1) LDR
2) Resistor (1k)
3) Battery
4) Transistor (2222A)

6. DESCRIPTION OF EACH
COMPONETS:
LDR-
 Sensitivity depends on intensity of light.
 Resistance of LDR decrease with increase in intensity
of light and vise-versa.

7. RESISTOR-
is a passive component having two terminals that are used
to mange the current It flow in the circuit.
A current that flows via a resistor is directly proportional to
the voltage that appeared into resistor.
Two types:
(1)Fixed value resistor
(2)Variable resistor
BATTERY-
A battery is device that converts chemical energy
contained within its active materials directly into electric
energy by means of an electrochemical oxidation reduction
reaction.

8. TRANSISTOR-
A transistor is a semiconductor device used to
amplify or
switch electrical signals and power. The transistor is one
of the basic building blocks of modern electronics. It is
composed of semiconductor material, usually with at least
three terminals for connection to an electronic circuit.

9. CIRCUIT DIAGRAM-

10. WORKING-
 Light falls on LDR , it shows its minimum resistance and
voltage drops across LDR less than voltage of transistor,
So no current will go from the collector to the emitter and
transistor remains turn off.
 It is automatically switches ON lights when the sunlight
goes below the region of our eyes. (in evening after
sunset)

11. RESULT-
Presence of External light Absence of External light

12. APPLICATIONS:
 Automatic lighting control.
 Balcony / Stair case / Parking lighting.
 Garden light.
 Smoke detection.
 They are also used in some clock, alarms, and other
electronic devices that are semi-dependent on sunlight.

13. DISADVANTAGES:
 It has a limitation of power.
 Light turns on when shadow falls on LDR
 LED is a low voltage device
ADVANTAGES:
 No man power required.
 Simple construction.
 Efficient method.
 Less maintenance.
 Cheap and economical.

14. CONCLUSION-
In coming days, this will prove a great boon
to the world, since it will save a lot of electricity of
power plants that gets wasted in illuminating the
street lights.
As the conventional sources are depleting
very fast, then it’s time to think of alternative.
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15. ENGINEERS