ON/OFF CONTROL OF ARTIFICIAL LIGHTS BASED ONSUNLIGHT AVAILIBILITY

Prepared under the guidance of Mr. Mousam Ghosh

(Assistant professor EEE dept.)

BY:-Manish Kumar SinghAmit Kumar MeenaAvinash Kumar

CONTENTS Introduction

Circuit Diagram

Isolated regulated power supply (5V-12V)

What is Power Supply Isolation?

Main Purposes of Power Supply Isolation

1)Safety

2)Voltage Level Shifting

3)Obtaining Multiple Output Converters

4)Ground Loop Prevention

555 timer used in its comparator mode

Switching control using transistor

The main controlling components used in circuit

1)Special Light detecting resistors

2)Relay

INTRODUCTION

The circuit that we have designed controls the amountof artificial light in a room, based on its brightness,occupancy, and sometimes other factors.

The project can be divided into three basic parts:-

1.Isolated Power Supply

2.Comparator using 555 timer

3.Switching circuit using transistor

CIRCUIT DIAGRAM

ISOLATED REGULATED POWER SUPPLY

Isolated regulated power supply is an electronic circuitthat is designed to provide a constant dc voltage ofpredetermined value across load terminals irrespectiveof ac mains fluctuations or load variations.

ISOLATED REGULATED POWER SUPPLY

What is Power Supply Isolation?In the context of power supply design, isolation is theelectrical and sometimes magnetic separation betweentwo circuits in close proximity to each other.

Main Purposes of Power Supply Isolation Safety

Voltage Level Shifting

Obtaining Multiple Output Converters

Ground Loop Prevention

555 timer used in its comparator mode

The 555 timer IC is an integrated circuit (chip) used in avariety of timer, pulse generation,and oscillator applications. The 555 can be used to providetime delays, as an oscillator, and as a flip-flop element.Derivatives provide up to four timing circuits in onepackage.

555 timer used in its comparator mode

The cicuit diagram that we have used in our project is shown below :-

Switching control using transistorThe difference this time is that to operate the transistor as a switchthe transistor needs to be turned either fully “OFF” (cut-off) orfully “ON” (saturated). An ideal transistor switch would haveinfinite circuit resistance between the Collector and Emitter whenturned “fully-OFF” resulting in zero current flowing through itand zero resistance between the Collector and Emitter whenturned “fully-ON”, resulting in maximum current flow.

Main controlling components used in circuit

(1)LDR (Light detecting resistors):-

LDRs (Light detecting resistors) will, as the name suggests, switch according to the ambient light levels irrespective of the time of day or when the sun officially rises or sets.

Main controlling components used in circuit

(2)Relay :-

A relay is an electrically operated switch Many relays usean electromagnet to mechanically operate a switch, butother operating principles are also used, such as solid-state relays

Hysteresis LoopThe hysteresis loop can be defined as the differencebetween the intensity of light required forswitching(ON/OFF) of the artificial light. Suppose thenatural light is getting closer to the LDR at an instant theartificial light gets turned on, now suppose the natural lightis getting farther from the LDR now the artificial light willturn off at another instant. So, the difference between thistwo intensities of light is called hysteresis loop. The twodifferent intensity level of light is required for switching onand off the artificial light. The intensity of light required forswitching on and off the artificial light can be controlled bythe potential divider.

Thank you