boolean led1 = true;
boolean buttonIsUp;
unsigned long timer;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  pinMode(13, OUTPUT);
  pinMode(4, INPUT_PULLUP);
  timer = millis();
  digitalWrite(13, false);
}

void loop() {
  led1 = !digitalRead(4);

  if  ((millis() - timer > 1000) and !buttonIsUp and led1 ) {
    digitalWrite(13, true);
    buttonIsUp = true;
    timer = millis();
  }
    
  if ((millis() - timer > 1000) and buttonIsUp and led1 ) {
    digitalWrite(13, false);
    buttonIsUp = false;
    timer = millis();
  }
  Serial.println(led1);
  Serial.println(timer);
  delay(10);
}