void setup() {

  pinMode(8, OUTPUT);
  pinMode(7, INPUT);
  Serial.begin(9600);
}

void loop() {
  
  int btn = digitalRead(7);
  
  if (btn == HIGH) {
    int sinalLed = digitalRead(8);

    digitalWrite(8, !sinalLed);
    delay(100);
    Serial.print(".");
  }

}