Automatic control of street light using LDR

Automatic Street Light Automatic Street Light control using LDRcontrol using LDR

Compiled by : Changela Savan IU124106008 Kavathiya Mit IU124106020 Loharikar Devang IU124106023 Zala Ajay IU124106062

Guided by:- Prof. Lalji Katariya

Contents

Planning of Project Introduction Circuit Diagram Hardware Requirement Description of Hardware Working Simulation Bread-board Mounting PCB Mounting Conclusion

Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Week 10 Week 11

Selection of topicProject ResearchAbstactPresentationHardware PurchasingBreadboard MountingSimulationPCB MountingProject ReportSubmission

Planning of Project

Introduction

Many of the people have a phobia of darkness, so 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 is very much easy and also the power consumed by the circuit is very low because of the very few components used in the circuit.

Circuit diagram

Components:

IC CA3140 – 1 Resistor R1 (10 K) – 1 Resistor R2 (3300 E) – 1 Resistor R3 (1 K) – 1 Variable Resistor VR1 (10 K) – 1 Capacitor C1 (10uF) – 1 LDR – 1 Transistor T1 (BC548) – 1 Relay-1 LED-1

Description of Hardware :

(1) LDR:

Sensitivity depends on intensity of light.Resistance of LDR decrease with increase in intensity of light and vice-versa.

(2) Resistor:It is a passive component having two terminals that are used to manage the current 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

(3)IC CA3140 :

IC

The CA 3140 is an operational amplifier can

works on supply voltage 4V to 36V & very low input current from 10pA to 1mA. Here, The CA3140 works as a comparatorand gives fast response &high speed.

(4) Relays

Relays is an electrically operated switch. Current flowing through the coil of the relay

creates a magnetic field which attracts a lever & changes the switch contacts.

It has 3-pin,4-pin,5-pin etc…but we have used 5-pin in our circuit diagram.

Relay offers easy way for LED to indicate a voltage is present at Relay coil.

As no input state, the COM is connectedTo NC & when operatingV is applied to relay coil Gets energized &COM Is now with NO.

(5) BC548 Transistor :

It is a general purpose silicon, NPN, bipolar junction transistor. It is used for amplification & switching purpose. Here, for switching purpose it is biased so that it remains on if there is signal at its base , other-wise it is completely off.

Working of Automatic Street Light Controller Switch Circuit:

The working of circuit is very much easy to understand. In this circuit, we used  IC CA3140 which is basically an operational amplifier. Pins 2 and 3 of these IC are used to compare the voltage and give us the output in return i.e. it works as a potential divider in its inverting and non-inverting inputs (pins 2 and 3).

Cont.

In this LDR and VR1 form one potential divider which is used to provide a variable voltage at the inverting input (that is 2) and the second potential divider is built around non-inverting input (pin 3) with the help of R1 and R2 which will grant half of the supply voltage to non inverting pin.

Cont.

As we know property of LDR that during the time of day resistance is low therefore voltage at the inverting input ( IE pin 2) is higher than the voltage at the non-inverting input (pin3) hence the output at the pin6 is low so the transistor goes into the cutoff state which means LED  or bulb will not glow.

Cont.

But in dimness or in night we know that resistance of LDR is high hence voltage at  inverting input pin 2 of the IC CA3140 decreases than the non inverting input pin 3 as a result output pin 6 moves to  high  state which make transistor to conduct and the LED or bulb associated to it start simmering.

Simulation (using Proteus):

3

2

74

6

1 58

U1

CA3140

R110k

R2330

RV1

10K

R3

1k

Q1BC548

C110u

GND

RL1RTE24005F

VCC Relay Supply

D1LED-GREEN

GND

12

LDR1TORCH_LDR

Bread-board mounting :

PCB mounting

Advantages:

No man power required. Simple Construction. Efficient method. Less Consumption of electrical energy. Less maintenance. Cheap and economical.

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 alternatives.