LDR with Arduino

Step 1: Hardware Required :

  • Arduino Uno
  • LED
  • LDR (photoresistor)
  • 220 and 10k ohm resistors
  • Wires
  • Breadboard

 Step 2: LED Connection


Picture of LED Connection

  1. LED attach to board
  2. Resistor (220 ohm) one leg attach to LED long leg
  3. The green wire attach to resistor's empty leg
  4. The brown wire attach o LED short leg



Step 3: LDR Connection


  1. LDR attach to board
  2. Resistor (10k ohm) attach to LDR one leg
  3. The purple wire attach to LDR other (empty) leg
  4. The yellow wire attach to LDR and resistor same column
  5. The white wire attach to resistor empty leg



 Step 4: Arduino Connections


  1. The green wire connect to digital 13 from resistor leg
  2. The brown wire connect to GND from LED short leg
  3. The purple wire connect to +5V from LDR
  4. The yellow wire connect to A0
  5. The white wire connect to GND


Step 5: Code



const int ledPin = 13;
const int ldrPin = A0;
void setup() {
pinMode(ledPin, OUTPUT);
pinMode(ldrPin, INPUT);
void loop() {
int ldrStatus = analogRead(ldrPin);
if (ldrStatus <=300) {
digitalWrite(ledPin, HIGH);
Serial.println("LDR is DARK, LED is ON");
else {
digitalWrite(ledPin, LOW);


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