int LED = 25;
int BTN = 26;
int STATE = 0;


void setup(){
  pinMode(BTN, INPUT);
  pinMode(LED, OUTPUT);
  Serial.begin(115200);

}

void loop() {

  while (digitalRead(BTN) == HIGH) {

    STATE = !STATE;
    digitalWrite(LED, STATE);
    delay(500);
    Serial.println(STATE);


}}