// Define the analog pin where the sensor is connected.
#define SENSOR_PIN A0
// Define the pin where the LED is connected.
#define LED_PIN 13
// Define the threshold value for the sensor output to trigger the LED.
#define THRESHOLD 500

// Variable to store the previous time the LED state was changed.
unsigned long previousMillis = 0;
// Interval at which the LED should blink (500ms).
const long interval = 500;
// Variable to store the current LED state.
int ledState = LOW;

/**
 * The setup function is called once at the start of the program.
 * It sets the LED pin as an output.
 */
void setup() {
  pinMode(LED_PIN, OUTPUT);
}

/**
 * The controlLedBlink function controls the blinking of the LED based on the sensor input.
 * It reads the sensor value and checks if it is above the threshold.
 * If the sensor value is above the threshold, it checks if it's time to change the LED state.
 * If it is time, it changes the LED state and sets the LED to the new state.
 * If the sensor value is below the threshold, it turns off the LED.
 */
void controlLedBlink() {
  int sensorValue = analogRead(SENSOR_PIN);  // Read the sensor value.

  if (sensorValue >= THRESHOLD) {  // Check if the sensor value is above the threshold.
    unsigned long currentMillis = millis();

    if (currentMillis - previousMillis >= interval) {  // Check if it's time to change the LED state.
      previousMillis = currentMillis;  // Save the last time the LED state was changed.

      if (ledState == LOW) {  // If the LED is off, turn it on. If it's on, turn it off.
        ledState = HIGH;
      } else {
        ledState = LOW;
      }

      digitalWrite(LED_PIN, ledState);  // Set the LED to the new state.
    }
  } else {
    digitalWrite(LED_PIN, LOW);  // If the sensor value is below the threshold, turn off the LED.
  }
}

/**
 * The loop function is called repeatedly after the setup function.
 * It calls the controlLedBlink function to control the LED blinking based on the sensor input.
 */
void loop() {
  controlLedBlink();
}