Using LDR sensor with Arduino | Arduino Day/Night Sensor Circuit using LDR (With daigram)

Hello everyone I'm Manitesla .In this post, you will learn how to use an LDR or Light Dependent resistor to turn on and off another circuit or a LED.

This project would help you in understanding how automatic day/ night activated LEDs work. Do you guys want to know how whenever a room gets dark, a light bulb automatically turns ON and the darkness disappears. In this very simple project, ill teach you everything you need to know to make your own day/light sensor.

A LDR (Light Dependent Resistor) or a photo resistor is a photo conductive sensor. It is a variable resistor and changes its resistance varies with light intensity. It’s resistance decreases with the intensity of light.

Circuit Diagram:

Arduino Code:

int led= 9;
void setup() {

Serial.begin(9600);

pinMode(led, OUTPUT);

pinMode(A0, INPUT);

}

void loop() {

int val = analogRead(A0);
Serial.println(val);
if (val <= 150) {

digitalWrite(led, HIGH);

} else {
digitalWrite(led, LOW);

} }