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Smart Night Light

Auto LED that switches with ambient light.

beginner30 min

Components Needed

Arduino UNO

LDR (photoresistor)

10kΩ resistor

LED + 220Ω resistor

Breadboard & wires

Circuit Diagram & Wiring

Add your circuit diagram image here.

LDR + 10kΩ as a divider on A0.
LED with 220Ω resistor on pin 9.
Common GND and 5V.

Arduino Sketch (.ino)

smart-light.ino

void setup() {
  pinMode(<span style="color:#79b8ff">9span>, OUTPUT);
}

void loop() {
  int light = analogRead(A0);
  <span style="color:<span style="color:#f97583">#6a737dspan>;font-style:italic">// darker → higher valuespan>
  int brightness = map(light, <span style="color:#79b8ff">0span>, <span style="color:#79b8ff">1023span>, <span style="color:#79b8ff">0span>, <span style="color:#79b8ff">255span>);
  analogWrite(<span style="color:#79b8ff">9span>, brightness);
}