 
     if (millis() - lastHeartBeat > heartBeatInterval) {
       Serial.println("loop running");
+      digitalWrite(LED_PIN, LOW);
+      delay(50);
+      digitalWrite(LED_PIN, HIGH);
       lastHeartBeat = millis();
     }
 }

#include <WiFiUdp.h>
#include <ArduinoOTA.h> 

const String THIS_NAME = String("ESP-") + ESP.getChipId();

int heartBeatInterval = 15000; // 15 seconds

void setup(void) {
    Serial.begin(115200); Serial.println();
    Serial.print(THIS_NAME); Serial.print(__DATE__);Serial.println(__TIME__);

    initWifi();
    Serial.print("WiFi connected to "); Serial.print(WiFi.SSID()); Serial.print(", IP address: "); Serial.println(WiFi.localIP());

    initOTA();
}

  ArduinoOTA.begin();
}

void ledBlink() {
  digitalWrite(LED_PIN, ! digitalRead(LED_PIN));
}

