This example is like a dark activated alarm using an LDR and a LED, in this case when the value read in drops below a certain level the LED will light. In the real world you could make a dark activated night light or alarm.
Its a fairly basic circuit, I connected the LED to D8, no real reason. LDR still connects to A0
Schematic and Layout
Code
int sensorPin = A0; // select the input pin for the ldr
int ledPin = 8; // select the pin for the LED
int sensorValue = 0; // variable to store the value coming from the sensor
void setup()
{
pinMode(ledPin, OUTPUT);
}
void loop()
{
sensorValue = analogRead(sensorPin);
if(sensorValue <= 400)
{
digitalWrite(ledPin, HIGH);
delay(500);
}
else
{
digitalWrite(ledPin, LOW);
}
}
