Description

LDR-based Automatic Light Control System

AIM:

To design an automatic light control system that turns ON or OFF based on the ambient light levels detected by an LDR sensor.

PURPOSE:

This system can automatically control lights by detecting the amount of ambient light. It turns the light ON when the light level is low (like during the night or in dark rooms) and turns it OFF when the light level is high (like during the daytime).

DESCRIPTION:

The LDR (Light Dependent Resistor) is a light-sensitive sensor whose resistance decreases as the ambient light intensity increases. In this system, the Arduino reads the resistance of the LDR using an analog pin. Based on the resistance, the Arduino controls the state of an attached relay that switches the light ON or OFF.

Key Components:

1.    Arduino Uno/Nano: The microcontroller that reads data from the LDR sensor and controls the relay to turn the light ON or OFF.

2.    LDR (Light Dependent Resistor): A sensor that changes its resistance based on the light intensity.

3.    Relay Module: Used to switch the light ON or OFF, as the Arduino cannot handle the high voltage directly.

4.    LED (optional): Used for indicating the status of the system (ON/OFF).

5.    Power Supply: 5V supply for the Arduino and sensor, 220V (AC) for the light.

WORKING:

1.    The LDR sensor is connected to the Arduino and is used to measure the intensity of the surrounding light.

2.    If the surrounding light is below a certain threshold (i.e., the room is dark), the Arduino will activate the relay, turning the light ON.

3.    If the surrounding light is above the threshold (i.e., the room is sufficiently lit), the Arduino will deactivate the relay, turning the light OFF.

4.    An LED may be used to indicate whether the light is ON or OFF.

TECHNICAL SPECIFICATIONS:

Hardware:

• Microcontroller: Arduino Uno/Nano
• LDR Sensor Module: To detect ambient light
• Relay Module: For switching high-voltage lights
• LED: Indicator for the light status
• Resistor: 10kΩ for LDR voltage divider
• Power Supply: 5V for Arduino, 220V for the light

Software:

• Arduino IDE: For writing and uploading the code to the Arduino
   

BLOCK DIAGRAM:

1.    LDR → Arduino → Relay → Light (AC/DC)

2.    Arduino → LED (Status Indicator)

CONNECTIONS:

1.    LDR Module:

·      VCC → 5V on Arduino

·      GND → GND on Arduino

·      Signal → Analog Pin A0 on Arduino

2.    Relay Module:

·      VCC → 5V on Arduino

·      GND → GND on Arduino

·      IN (Signal Pin) → Digital Pin 7 on Arduino

·      COM → Common (light) terminal

·      NO → Normally Open terminal (for light control)

3.    LED:

·      Anode → Digital Pin 13 on Arduino

·      Cathode → GND through 220Ω resistor

4.    Light (AC or DC):

·      Controlled by the relay’s COM and NO terminals.

APPLICATIONS:

1.    Residential Use: Automatically controls lights in homes, saving energy.

2.    Offices: Automatically turns lights ON/OFF based on natural light availability.

3.    Street Lighting: Turns streetlights ON at dusk and OFF at dawn.

 

ADVANTAGES:

1.    Energy Saving: Ensures that lights are only ON when necessary, saving electricity.

2.    Convenience: Automates the process of controlling lights, making it more convenient for users.

3.    Low-Cost: Uses simple components like an LDR and relay for cost-effective automation.

FUTURE ENHANCEMENTS:

1.    Integrate a Dawn/Dusk sensor for more precise control over light switching based on actual sunlight levels.

2.    Implement Wi-Fi/Bluetooth for remote control or monitoring of the system.

3.    Add an adjustable threshold for more flexible light control based on environmental changes.

4.    Use a sensor module with a wider detection range to control multiple lights in large rooms or spaces.

This LDR-based Automatic Light Control System is an effective and simple solution for automating light control based on the surrounding light conditions.