/*
 NightLight
 Turn an LED on when the ambient light is below a certain value.
 */

const int lightThreshold = 800;  // value below which LED turns on
const int inputPin = A0;         // use analog 0 (A0) as input pin
const int ledPin = 13;           // connect the LED to pin 13

int lightLevel = 0;              // used to store the input value

void setup() {
  pinMode(ledPin, OUTPUT);       // make LED's pin an output
}

void loop() {
  lightLevel = analogRead(inputPin);  // get an analog reading      

  if (lightLevel <= lightThreshold)
    digitalWrite(ledPin, HIGH);       // turn the LED on
  else
    digitalWrite(ledPin, LOW);        // turn the LED off
}