Published March 2, 2020 © GPL3+

Light Sensor Using Arduino

The Project is about switching on the light if necessary (i. e in darkness) and switching off the light when there is enough brightness.

BeginnerFull instructions provided2 hours64,691

Things used in this project

Hardware components

Arduino UNO

LDR, 5 Mohm

LED (generic)

Jumper wires (generic)

Resistor 10k ohm

Resistor 220 ohm

Software apps and online services

Arduino IDE

Story

Hi Guys! Wouldn’t it be really cool if whenever a room gets dark, a light bulb automatically turns ON and eliminates the darkness? In this very simple project, I am focusing on eliminating darkness. You can even use this as an emergency lighting system.

Steps:

Connect the 3.3V of arduino to the positive rail and ground to the negative rail of breadboard.

Connections for LDR sensor:

Place the LDR on the breadboard and attach the 10k ohm resistor to one of the legs of LDR. Connect the A0 pin of arduino to the same column of resistor and LDR.
This is to fetch the intensity of light from LDR to the arduino through A0 pin.
Connect the other end of resistor to the negative rail of breadboard.
Connect the other end of LDR to the positive rail of breadboard.

LDR connections

Connections for LED:

Place LED on breadboard and connect positive end of LED to the 220ohm resistor.
Connect the other end of resistor to the pin 13 of arduino.
Connect the negative end of LED to the negative rail of breadboard.

LED connections

The setup is now ready. Now load the code in Arduino IDE and then upload it to Arduino. Check the light intensity near LDR. Try changing the Brightness of light near LDR sensor.

The Final Project:

Code

Light Sensor using Arduino

const int ledPin = 13;
const int ldrPin = A0;
void setup() {
  Serial.begin(9600);
  pinMode(ledPin, OUTPUT);
  pinMode(ldrPin, INPUT);
}

void loop() {
  int ldrStatus = analogRead(ldrPin);

  if (ldrStatus <= 400)
  {
    digitalWrite(ledPin, HIGH);
    Serial.print("Its Dark, Turn on the LED:");
    Serial.println(ldrStatus);

  }
  else
  {
    digitalWrite(ledPin, LOW);
    Serial.print("Its Bright, Turn off the LED:");
    Serial.println(ldrStatus);
  }

}

Credits

Nikhileswari

2 projects • 5 followers