Photo Blink

Here we add a photoresistor to the Blink circuit. We use this to sense the amount of light in the room, and adjust the blink rate – the darker the room, the faster the LED blinks.

photo_blink.ino

const int ledPin = 3;     // LED connected to pin 3
const int sensorPin = 0;  // photoresistor on analog 0
 
// minimum and maximum blink rates
const int minDuration = 100;
const int maxDuration = 1000;
 
void setup() {
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600);
}
 
void loop() {
  int rate = analogRead(sensorPin);
  Serial.println(rate);
//  rate = map(rate, 0, 800, minDuration, maxDuration);
  digitalWrite(ledPin, HIGH);
  delay(rate);
  digitalWrite(ledPin, LOW);
  delay(rate);
}