This document describes an automated light illumination controller that uses light dependent resistors (LDRs) and a comparator circuit to automatically switch lights on and off based on light intensity. The circuit works by using an LDR to detect changes in light levels, which changes the LDR's resistance and manipulates voltages in the circuit. When light levels drop, the secondary circuit is activated and the light bulb turns on. The document also discusses how the LDR can be replaced with other sensors like smoke, infrared, or temperature sensors to create devices like fire alarms, burglar alarms, or temperature-controlled lighting or heating systems. It concludes by discussing how this technology enables the development of smart homes.

1. AUTOMATED LIGHT ILLUMINATION CONTROLLER
Project Guide:
Prof. Shweta Alpna
Presented By:
Bhavya Sonal (1104064)
Bibhu Prasad Sahu (1104065)
SCHOOL OF ELECTRONICS ENGINEERING

2. INTRODUCTION
 Traditional switching based on mechanical ON/OFF (manual
power).
 Dependency upon human judgment.
 ‘Smart Homes’ to become the norm in the future.
 Automated devices to replace the traditional ones.
 Automation to be done using sensors and transducers.

3. PRINCIPLE
 Sensors and transducers to detect changes in the surroundings.
 Sensors can be of various types depending upon the nature of the
appliance.
 Automated Light Illumination Controller works on the principle of LDR.
 Change in the intensity of incident light results in change in resistance.
 Voltages are manipulated resulting in automated switching action.
 Secondary circuit gets activated and light bulb starts glowing.

4. CIRCUIT DIAGRAM

5. CIRCUIT OPERATION
Voltage Regulation

6. CIRCUIT OPERATION
Comparator inputs

7. CIRCUIT OPERATION
Transistor switching

8. CIRCUIT OPERATION
Triggering the Relay

9. CIRCUIT OPERATION
Completion of Secondary Circuit

10. PRACTICAL IMPLEMENTATION
 When LDR is replaced by a smoke sensor, then a fire alarm can be
designed which goes off on detecting smoke.
 When LDR is replaced by an infrared sensor, then it can detect intruders
and hence the burglar alarm goes off.
 By using a temperature sensor in place of LDR, switching can be done to
turn ON either an AC or a Radiator, depending upon the temperature
(weather) outside.
…contd.

11. BURGLAR ALARM
 A feature can be added which uses a sensor to detect intruder activity and when the
device is triggered, it should send the GPS coordinates to the nearby police station and
to the owner's handheld device.
 Infrared camera can be used along with it to capture the image of burglar before the
police gets there.
 Sensors used in burglar alarms:
 PIR: This sensor is passive in the sense that it captures the heat emitted from the objects.
Therefore, it needs a clear sight of vision. As human body emits more heat, the sensor can
detect the presence of intruders.
 Ultrasonic detectors: These sensors send ultrasonic sound waves and receive them as they
bounce back from the fixed objects in the room. So, if any object moves, the wavelength
changes and the sensor detects moving object.
 Microwave detectors: This type of sensor emits microwaves and detects discrepancies in the
signals through the receiver.
…contd.

12. SMART HOMES
 A switch can be added which when switched ON by the user when he is at home,
would bypass the relay trigger system and function as a normal light and a dimmer
incorporated.
 When the owner goes out, then switch would be OFF and relay trigger would be in
active state, thereby making all automated devices interconnected to one another
as well as with the user.
 This technology is named as the ‘Internet of things’ which refers to the objects and
products that are interconnected and identifiable through digital networks.
 Uses of smart homes:
 Switch thermostat on after getting up from bed
 Unlock door automatically as you approach
 Notify the resident about important events and tasks
 Makes life easy for elderly and physically disabled people.

13. THANK YOU