int led1_pin = 13;
 long currentTime,lastTime;
 bool led_state = LOW;
 int delayTime = 1000;



void setup() {
  pinMode(led1_pin, OUTPUT);
  Serial.begin(9600);

  // put your setup code here, to run once:

}

void loop() {

  currentTime = millis();
  Serial.println(currentTime);


  if(currentTime - lastTime>800){
    led_state = !led_state;
    lastTime = currentTime;
  }

  digitalWrite(led1_pin, led_state);
  // put your main code here, to run repeatedly:

}