スケッチは下記の通り、「05.Control」の「IfStatementConditional」を改造したもの。部屋が暗くて常点灯になってしまったので、オンオフの境界となる閾値（threshold）を250から150に下げた。

[ スケッチ：IfStatementConditional1]

// These constants won't change:
const int analogPin = A0;    // pin that the sensor is attached to
const int ledPin = 13;       // pin that the LED is attached to
const int threshold = 150;   // an arbitrary threshold level that's in the range of the analog input
void setup() {
  // initialize the LED pin as an output:
  pinMode(ledPin, OUTPUT);
  // initialize serial communications:
  Serial.begin(9600);
}
void loop() {
  // read the value of the potentiometer:
  int analogValue = analogRead(analogPin);
  // if the analog value is high enough, turn on the LED:
  if (analogValue < threshold) {
    digitalWrite(ledPin, HIGH);
  } else {
    digitalWrite(ledPin, LOW);
  }
  // print the analog value:
  Serial.println(analogValue);
  delay(1);        // delay in between reads for stability
}

実際に点灯させたところ（動画）