diff --git a/main/esp32-sensornode_main.cpp b/main/esp32-sensornode_main.cpp
index e297a56..bfc494c 100644
--- a/main/esp32-sensornode_main.cpp
+++ b/main/esp32-sensornode_main.cpp
@@ -65,7 +65,9 @@ String         serviceUri         = "/write?db=test";
 #endif
 
 /* GLOBAL VARIABLES */
-const unsigned int wifiConnectTimeout = 30; /* num of 500ms intervals */
+const uint16_t wlanConnectCheckInterval  = 250;   /* milli seconds: poll wifi.state after wifi.begin() */
+const uint16_t wlanConnectTimeout        = 15000; /* milli seconds */
+RTC_DATA_ATTR uint8_t wlanConnectFailCnt = 0;
 
 Si7021 si7021 = Si7021();
 float  temp   = 0.0;
@@ -74,7 +76,7 @@ float  humi   = 0.0;
 uint16_t battLevel = 0;
 float    battPerc  = 0.0;
 
-RTC_DATA_ATTR uint8_t sampleCnt = 0;
+RTC_DATA_ATTR uint8_t sampleCnt = 0;    // for average value
 RTC_DATA_ATTR float   tempAccu  = 0.0;  // for average value
 RTC_DATA_ATTR float   humiAccu  = 0.0;  // for average value
 
@@ -102,11 +104,10 @@ bool wlanConnect(void) {
   WiFi.mode(WIFI_STA);
   WiFi.begin(wlan_ssid, wlan_passwd);
   while (WiFi.status() != WL_CONNECTED) {
-    delay(500);
+    delay(wlanConnectCheckInterval);
     INFO_PRINT(".");
-
     cycles++;
-    if (cycles > wifiConnectTimeout) {
+    if (cycles > wlanConnectTimeout / wlanConnectCheckInterval) {
       INFO_PRINTLN(" FAILED");
       return false;
     }
@@ -154,10 +155,10 @@ void printWakeupReason() {
 }
 
 extern "C" void app_main() {
+  // ESP32 Setup
   initArduino();
   pinMode(4, OUTPUT);
   digitalWrite(4, HIGH);
-  //do your own thing
 
 #ifdef PRINT_INFO
   Serial.begin(115200);
@@ -173,10 +174,6 @@ extern "C" void app_main() {
   printWakeupReason();
 #endif
 
-  // switch WiFi off for the moment
-  DEBUG_PRINTLN("[DEBUG] Turning wifi off for now");
-  WiFi.mode(WIFI_OFF);
-
   // setup the si7021 sensor
   if (false == si7021.begin()) {
     INFO_PRINTLN("[ERROR] SI7021 not set up properly");
@@ -200,26 +197,21 @@ extern "C" void app_main() {
 
 #ifdef PRINT_INFO
   Serial.printf("[INFO ] > Humidity: %5.2f  Temperature: %5.2f", humi, temp);
-  Serial.printf("  Battery Bat: %5.1f /100 (raw: %4d)\n", battPerc, battLevel);
+  Serial.printf("  Battery Bat: %5.1f/100 (raw: %4d)\n", battPerc, battLevel);
 #endif
 
   /* ---------- MAIN LOGIC START ---------- */
   // accumulate and average $sampleAvgNum samples before sending data
-  if (sampleCnt < sampleAvgNum) {
-    sampleCnt++;
-    tempAccu += temp;
-    humiAccu += humi;
-  }
+  sampleCnt++;
+  tempAccu += temp;
+  humiAccu += humi;
 
   // calculate average and send data, if $sampleAvgNum are reached
   if (sampleCnt >= sampleAvgNum) {
 
     INFO_PRINTLN("[INFO ] Enough samples collected -> send average to database");
-    temp      = tempAccu / (float)sampleCnt;
-    humi      = humiAccu / (float)sampleCnt;
-    sampleCnt = 0;
-    tempAccu  = 0;
-    humiAccu  = 0;
+    temp = tempAccu / (float)sampleCnt;
+    humi = humiAccu / (float)sampleCnt;
 #ifdef PRINT_INFO
     Serial.printf("[INFO ] < Humidity: %5.2f  Temperature: %5.2f\n", humi, temp);
 #endif
@@ -253,6 +245,13 @@ extern "C" void app_main() {
             if (line.indexOf("204") == -1) {  // expect a HTTP 204 status code
               INFO_PRINTLN("[ERROR]: invalid http status code");
               INFO_PRINTLN(line);
+            } else {  // successful database submission
+              // reset average after successful database submission
+              sampleCnt = 0;
+              tempAccu  = 0;
+              humiAccu  = 0;
+
+              wlanConnectFailCnt = 0;
             }
             break;
           } else {
@@ -270,11 +269,15 @@ extern "C" void app_main() {
     } else {  // ELSE: !wifiConnect
 
       /* WIFI CONNECT FAILED, WAIT MAX 5 MINUTES IN DEEP SLEEP */
-      INFO_PRINTLN("[INFO ] WiFi connect failed -> wait a bit and try again");
-      if (sendInterval_sec > (5 * 60)) {
+      wlanConnectFailCnt++;
+#ifdef PRINT_INFO
+      Serial.printf("[INFO ] WiFi connect failed %d time(s) -> wait %03d s and try again\n",
+                    wlanConnectFailCnt, sampleInterval_sec);
+#endif
+      if (sampleInterval_sec > (5 * 60)) {
         doDeepSleep(5 * 60);
       } else {
-        doDeepSleep(sendInterval_sec);
+        doDeepSleep(sampleInterval_sec);
       }
     }  // ENDIF: wifiConnect