LDR sensor

LDR sensor

An LDR sensor, or Light Dependent Resistor, is a type of resistor whose resistance decreases with increasing light intensity. This means that the LDR sensor becomes less resistant when it is exposed to light.

Working of LDR

LDR sensors work on the principle of photoconductivity. Photoconductivity is the property of a material that increases its electrical conductivity when exposed to light. In the case of an LDR sensor, the light causes electrons to be excited from the valence band to the conduction band, which increases the number of free electrons in the material. This increase in free electrons leads to a decrease in resistance.

Applications of LDR sensors

LDR sensors have a wide variety of applications, including:

  • Light intensity measurement
  • Automatic light switches
  • Security systems
  • Motion detectors
  • Plant growth monitoring
  • Street lighting control
  • Cameras
  • Robotics

How to use an LDR sensor

To use an LDR sensor, you will need to connect it to a device that can read the sensor’s output. This device could be a smartphone, a computer, or an Arduino board.

Once the sensor is connected, you can write code to read the sensor’s output and print it to the Serial Monitor. You can also use the sensor’s output to control other devices, such as LEDs or motors.

Interfacing Arduino with LDR sensor

To interface an Arduino board with an LDR sensor, you will need to connect the sensor’s output pin to an analog input pin on the Arduino board. You will also need to connect the sensor’s power and ground pins to the Arduino board’s power and ground pins.

Once the connections are made, you can write code to read the sensor’s output and print it to the Serial Monitor. You can also use the sensor’s output to control other devices, such as LEDs or motors.

Here is an example of LDR sensor code:

Code 

// This code reads the output of an LDR sensor and prints it to the Serial Monitor.

// Import the necessary libraries
import processing.serial.*;

// Define the serial port
Serial myPort;

// Define the LDR sensor pin
int sensorPin = A0;

void setup() {
  // Initialize the serial port
  myPort = new Serial(this, "COM3", 9600);

  // Set the LDR sensor pin as an input
  pinMode(sensorPin, INPUT);
}

void loop() {
  // Read the value from the LDR sensor
  int sensorValue = analogRead(sensorPin);

  // Print the sensor value to the Serial Monitor
  myPort.println(sensorValue);

  // Wait for 10 milliseconds
  delay(10);
}

Use code with caution.

This code will first import the necessary libraries. It will then define the serial port and the LDR sensor pin.

In the setup function, the code will initialize the serial port and set the LDR sensor pin as an input.

In the loop function, the code will read the value from the LDR sensor and print it to the Serial Monitor. It will then wait for 10 milliseconds before repeating the process.

To run this code, you will need to connect the LDR sensor to the Arduino board and the Arduino board to your computer. You will also need to install the Processing software.

Once you have installed the Processing software, you can open the code in Processing and click the “Run” button. The Serial Monitor will start displaying the value from the LDR sensor.

«

»

x