int sensorPin = A0; //ambient light sensor input int ledPin = 9; //led output void setup() //initialize { pinMode(ledPin, OUTPUT); // Serial.begin(57600); } void loop() //run { int sensorValue = analogRead(sensorPin); //read data // Serial.println(sensorValue); // delay(200); if(sensorValue<150) digitalWrite(ledPin, HIGH); else digitalWrite(ledPin, LOW); }