Arduino powered nightlight

nightlight.ino

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);    // Here, we're initializing communication from the arduino back to the computer
  pinMode(3,OUTPUT);    // Here, we're setting pin D3 as an output pin.
}

void loop() {
  // put your main code here, to run repeatedly:

  int sensorValue = analogRead(A2); // Reading the photosensor
  Serial.println(sensorValue);      // sending that value back to the computer just so we know

  if (sensorValue < 500){           // if the sensor is seeing less than 500 units of light...
                                       // we determined that 500 was roughly the threshold between bright and dark
    digitalWrite(3, HIGH);          // turn the light on
  }else {                           // otherwise...
    digitalWrite(3, LOW);           // turn the light off
  }
  delay(500);                       // wait half a second and begin again.
}