#define led 2
#define btn 4
int estadobtn = 0;

void setup() {
  pinMode(led, OUTPUT);
  pinMode(btn, INPUT);
}

void loop() {
  estadobtn = digitalRead(btn);
  if (estadobtn == 1) {
    digitalWrite(led, HIGH);
  }
  else {
    digitalWrite(led, LOW);
  }
}