const int photodiodePin = A0;

const int ledPin = 13;

int sensorValue = 0;

int threshold = 50; // Adjust this value based on your ambient light

unsigned long turnOnTime = 0;

unsigned long turnOffTime = 0;

​

void setup() {

  pinMode(ledPin, OUTPUT);

  Serial.begin(9600);

}

​

void loop() {

  sensorValue = analogRead(photodiodePin);

  Serial.println(sensorValue);

  if (sensorValue < threshold) {

    if (digitalRead(ledPin) == LOW) {

      turnOnTime = millis();

      Serial.print("LED turned on at: ");

      Serial.println(turnOnTime);

    }

    digitalWrite(ledPin, HIGH); // Turn on the LED

  } else {

    if (digitalRead(ledPin) == HIGH) {