1.Using an LDR (Light Dependent Resistor) with Arduino to Measure Light Intensity

 Using an LDR (Light Dependent Resistor) with Arduino to Measure Light Intensity.

Components Needed:

1. Arduino board
2. LDR (photoresistor)
3. 10kΩ resistor
4. Breadboard and jumper wires

Circuit Connections:

1. LDR: Connect one leg of the LDR to 5V on the Arduino, and the other leg to an analog input pin (e.g., A0).
2. Resistor: Connect a 10kΩ resistor between the LDR leg (that goes to the analog pin) and GND. This forms a voltage divider.

Explanation:

• When light falls on the LDR, its resistance changes, affecting the voltage at the analog pin.
• The analog pin reads a value between 0 and 1023 depending on the light intensity.

Example Code:

C++ Code

int ldrPin = A0; // Analog pin to which LDR is connected
int ldrValue;

void setup() {
  Serial.begin(9600); // Start the serial communication to view the LDR value
}

void loop() {
  ldrValue = analogRead(ldrPin); // Read the LDR value
  Serial.println(ldrValue); // Print the value to the Serial Monitor
  delay(500); // Delay for half a second
}

Explanation of Code:

• analogRead(ldrPin) reads the value from the LDR, which will vary based on light intensity.
• You can use this value to trigger actions, such as turning on LEDs when it gets dark or adjusting the brightness of a display.