#define LED_PIN 13
#define POTENTIOMETER_PIN A0
#define BUTTON_PIN 8
#define ONE_SECOND 1000

int previousButtonValue = 0;
int currentButtonValue = 0;
float potentiometerValue = 0;
int ledValue = 0;

void setup() {
  pinMode(LED_PIN, INPUT);
  pinMode(BUTTON_PIN, INPUT);
}

void loop() {
  currentButtonValue = digitalRead(BUTTON_PIN);

  if (currentButtonValue == 1 && currentButtonValue != previousButtonValue) {
    ledValue = abs(ledValue - 1);
    digitalWrite(LED_PIN, ledValue);
  }

  previousButtonValue = currentButtonValue;
  delay(ONE_SECOND / 2);
}