Introduction

This project aims for an advanced electricity saving system. By taking the help of modern engineering and technology we are designing a sensor based system which will avoid the wastage of electrical energy. This process is cost reducing and saves a lot of energy and money in a long term basis. We have designed an auto switching of light bulbs, which avoids the unnecessary consumption of electricity during day time.

Rationale

Generally we forget to switch the light bulbs off in our garden, top of the roof, backside of house at dawn. So, during day time we can’t visualize it. To avoid unnecessary consumption of electricity and save electricity we have adopted this project.

Block Diagram

Scientific principle

Resistance of the LDR decreases when light falls on it, Resistance of the LDR increases when there is no light. This principle activates and deactivates the circuit here.

Materials required

1. Transformer
2. Resistors
3. IC555
4. Hard Board
5. LED
6. Connecting Wires
7. Diodes
8. Capacitors
9. Screws
10. Sun board
11. Transistors
12. Switch
13. Relay
14. Light Bulb

Construction

The components are connected appropriately as in the circuit diagram .The circuits are mounted on the board.

Rectifier circuit diagram

LDR circuit diagram

Working

At the starting of the day when the horizon is illuminated by sun rays, the lighting system at roof and backside of home are turned off automatically. LDR Stands for Light Dependant Resistor. LDR is a kind of variable resistor and its resistance value varies depending on the intensity of light falling on it. In dark, LDR offers extremely high resistance as high as 10 Mega Ohm but it reduces to 100 Ohms or less in bright light. So, LDR is an ideal light sensor when our circuit has a dependency parameter as sun light. We have used a 5mm diameter LDR here. At the starting of evening when darkness arrives the light bulbs are illuminated automatically. This process avoids the wastage of electricity if we forget to switch off those at day time. 

Advantage

This project avoids unnecessary wastage of electricity.

As a result it saves electric bill also.