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How Does an Arduino Light Sensor Work?

Published in Electronics 2 mins read

An Arduino light sensor, also known as a photoresistor, measures the intensity of light by changing its resistance.

How it Works:

  • Light Sensitivity: The photoresistor's resistance decreases as the amount of light falling on it increases.
  • Voltage Divider: The sensor is typically connected in a voltage divider circuit with a fixed resistor.
  • Analog Input: The Arduino reads the voltage across the photoresistor, which is proportional to the light intensity.
  • Interpretation: The Arduino translates this voltage into a digital value, allowing you to measure and control light levels.

Practical Applications:

  • Automatic Lighting: Control lights based on ambient light levels, turning them on at dusk and off at dawn.
  • Light-Activated Alarm: Trigger an alarm when a light source is detected.
  • Robotics: Use light sensors for obstacle avoidance or line-following robots.
  • Plant Monitoring: Monitor light levels for optimal plant growth.

Example Code:

const int lightSensorPin = A0; // Analog input pin for the light sensor

void setup() {
  Serial.begin(9600); // Start serial communication
}

void loop() {
  int lightValue = analogRead(lightSensorPin); // Read the light sensor value
  Serial.print("Light Value: ");
  Serial.println(lightValue); // Print the light value to the serial monitor
  delay(100); // Pause for 100 milliseconds
}

This code reads the analog value from the light sensor and prints it to the serial monitor. You can use this value to control other components or implement different applications.

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