Interface LDR with Arduino

ARDUINO

LDR

Description

An LDR (Light Dependent Resistor) is a type of sensor that changes its resistance based on the amount of light falling on it. It is also commonly referred to as a photoresistor.LDRs can be used in light-sensitive circuits to activate or deactivate devices based on ambient light conditions. For example, they can be employed in automatic streetlights that turn on at dusk and turn off at dawn.

Sensor Details

Maximum power dissipation is 200mW
The maximum voltage at 0 lux is 200V
The peak wavelength is 600nm
Minimum resistance at 10lux is 1.8kΩ
Maximum .resistance at 10lux is 4.5kΩ
Typical resistance at100lux is 0.7kΩ
Dark resistance after 1 sec is 0.03MΩ
Dark resistance after 5 sec is 0.25MΩ

Wiring Details

LDR sensor positive point to Arduino 5V

LDR sensor negetive point to Arduino A3

1000k Resistors positive point to arduino A3

1000k Resistor negative point to Arduino Gnd

Bulb positive point to Arduino 12

Bulb negetive point to Arduino Gnd

Circuit Image

Circuit Code

                                        
                                            //start coding

const int Bulb = 12;

int ADC_value;

void setup() {

pinMode(Bulb, OUTPUT);

Serial.begin(9600);

}

void loop() {

ADC_value = analogRead(A3);

Serial.println(ADC_value);

delay(1000);

if (analogRead(A3) > 100) {

digitalWrite(Bulb, HIGH);

}

else{

digitalWrite(Bulb, LOW);

}

}