diff --git a/platformio.ini b/platformio.ini
index 7982363..2fc5abd 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -4,3 +4,4 @@ board = esp12e
 framework = arduino
 lib_deps = https://github.com/thorsten-gehrig/arduino-tpuart-knx-user-forum
            https://github.com/knolleary/pubsubclient
+           https://github.com/me-no-dev/ESPAsyncWebServer
\ No newline at end of file
diff --git a/src/Group.cpp b/src/Group.cpp
new file mode 100644
index 0000000..18c9d0b
--- /dev/null
+++ b/src/Group.cpp
@@ -0,0 +1,20 @@
+#include "Group.h"
+
+#include <mqtt.h>
+
+Group groups[500];
+
+Group *groupCache(KnxTelegram *telegram) {
+  for (auto &&group: groups) {
+    if ((group.main == 0 && group.mid == 0 && group.sub == 0) || (group.main == telegram->getTargetMainGroup() && group.mid == telegram->getTargetMiddleGroup() && group.sub == telegram->getTargetSubGroup())) {
+      group.main = telegram->getTargetMainGroup();
+      group.mid = telegram->getTargetMiddleGroup();
+      group.sub = telegram->getTargetSubGroup();
+      group.timestamp = time(nullptr);
+      group.value = static_cast<double>(telegram->get1ByteIntValue()) + telegram->get2ByteIntValue() + (telegram->get4BitDirectionValue() ? telegram->get4BitStepsValue() : -telegram->get4BitStepsValue()) + telegram->get2ByteFloatValue() + telegram->get4ByteFloatValue();
+      return &group;
+    }
+  }
+  mqttLogError("group cache full");
+  return nullptr;
+}
diff --git a/src/Group.h b/src/Group.h
index 1d36d5a..8df60e6 100644
--- a/src/Group.h
+++ b/src/Group.h
@@ -1,6 +1,8 @@
 #ifndef GROUP_H
 #define GROUP_H
 
+#include <KnxTpUart.h>
+
 class Group {
 
 public:
@@ -11,18 +13,14 @@ public:
 
   uint8_t sub = 0;
 
-  uint8_t dpt = 0;
+  time_t timestamp = 0;
 
-  static Group groups[500];
-
-  static void write(uint8_t main, uint8_t mid, uint8_t sub) {
-    for (auto group: groups) {
-      if (group.main == main && group.mid == mid && group.sub == sub) {
-        group.
-      }
-    }
-  }
+  double value = 0;
 
 };
 
+extern Group groups[];
+
+Group *groupCache(KnxTelegram *telegram);
+
 #endif
diff --git a/src/http.cpp b/src/http.cpp
new file mode 100644
index 0000000..1079852
--- /dev/null
+++ b/src/http.cpp
@@ -0,0 +1,9 @@
+#include "http.h"
+
+#include <ESPAsyncWebServer.h>
+
+AsyncWebServer server(80);
+
+void httpSetup() {
+  server.begin();
+}
\ No newline at end of file
diff --git a/src/http.h b/src/http.h
new file mode 100644
index 0000000..abcba1f
--- /dev/null
+++ b/src/http.h
@@ -0,0 +1,6 @@
+#ifndef HTTP_H
+#define HTTP_H
+
+void httpSetup();
+
+#endif
diff --git a/src/knx.cpp b/src/knx.cpp
new file mode 100644
index 0000000..f23823e
--- /dev/null
+++ b/src/knx.cpp
@@ -0,0 +1,45 @@
+#include "knx.h"
+#include "Group.h"
+#include "wifi.h"
+#include "time_.h"
+#include "mqtt.h"
+
+#include <KnxTpUart.h>
+
+KnxTpUart knx(&Serial1, "15.15.20");
+
+void sendGroup(Group *group);
+
+void knxSetup() {
+  Serial1.begin(19200, SERIAL_8E1);
+  knx.uartReset();
+  knx.setListenToBroadcasts(true);
+}
+
+void knxLoop() {
+  if (knx.serialEvent() != KNX_TELEGRAM) {
+    return;
+  }
+
+  KnxTelegram *telegram = knx.getReceivedTelegram();
+  mqttLogInfo("received: %d/%d/%d", telegram->getTargetMainGroup(), telegram->getTargetMiddleGroup(), telegram->getTargetSubGroup());
+
+  Group *group = groupCache(telegram);
+  sendGroup(group);
+}
+
+void sendGroup(Group *group) {
+  if (group == nullptr || !isTimeSet() || !isWiFiConnected()) {
+    return;
+  }
+
+  correctTime(&group->timestamp);
+
+  char topic[64];
+  snprintf(topic, sizeof topic, "knx/group/%d/%d/%d", group->main, group->mid, group->sub);
+
+  char payload[128];
+  snprintf(payload, sizeof payload, "%d/%d/%d %lld %f", group->main, group->mid, group->sub, group->timestamp, group->value);
+
+  mqttPublish(topic, payload);
+}
diff --git a/src/knx.h b/src/knx.h
new file mode 100644
index 0000000..65417b3
--- /dev/null
+++ b/src/knx.h
@@ -0,0 +1,8 @@
+#ifndef KNX_H
+#define KNX_H
+
+void knxSetup();
+
+void knxLoop();
+
+#endif
diff --git a/src/main.cpp b/src/main.cpp
index 16df186..dc69a71 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,70 +1,25 @@
 #include <Arduino.h>
-#include <ESP8266WiFi.h>
-#include <KnxTpUart.h>
-#include <PubSubClient.h>
 
-KnxTpUart knx(&Serial1, "15.15.20");
-
-PubSubClient mqtt;
-
-void knxSetup();
-
-void knxLoop();
-
-void mqttLoop();
-
-void mqttSetup();
-
-void wifiSetup();
+#include "knx.h"
+#include "wifi.h"
+#include "time_.h"
+#include "mqtt.h"
+#include "http.h"
 
 void setup() {
-  Serial.begin(112500);
   delay(500);
+  Serial.begin(112500);
   Serial.print("\n\n\nStartup\n");
   knxSetup();
   wifiSetup();
-  configTime("Europe/Berlin", "de.pool.ntp.org");
+  timeSetup();
   mqttSetup();
-}
-
-void wifiSetup() {
-  WiFi.hostname("KnxEsp");
-  WiFi.begin("HappyNet", "1Grausame!Sackratte7");
-  while (WiFi.localIP() == 0UL) {
-    delay(100);
-  }
-
+  httpSetup();
 }
 
 void loop() {
   knxLoop();
+  wifiLoop();
+  timeLoop();
   mqttLoop();
 }
-
-void mqttSetup() {
-  mqtt.setServer("10.0.0.50", 1883);
-  mqtt.setBufferSize(512);
-}
-
-void mqttLoop() {
-  if (!mqtt.loop()) {
-    if (!mqtt.connect(WiFi.hostname().c_str())) {
-      mqtt.disconnect();
-    }
-  }
-}
-
-void knxSetup() {
-  Serial1.begin(19200, SERIAL_8E1);
-  knx.uartReset();
-  knx.setListenToBroadcasts(true);
-}
-
-void knxLoop() {
-  auto type = knx.serialEvent();
-  if (type != KNX_TELEGRAM) {
-    return;
-  }
-  KnxTelegram *t = knx.getReceivedTelegram();
-  Serial.printf("%3d / %3d / %3d len=%d, bool=%d\n", t->getTargetMainGroup(), t->getTargetMiddleGroup(), t->getTargetSubGroup(), t->getPayloadLength(), t->getBool());
-}
diff --git a/src/mqtt.cpp b/src/mqtt.cpp
new file mode 100644
index 0000000..4753e87
--- /dev/null
+++ b/src/mqtt.cpp
@@ -0,0 +1,56 @@
+#include "mqtt.h"
+#include "wifi.h"
+
+#include <ESP8266WiFi.h>
+#include <PubSubClient.h>
+
+PubSubClient mqtt;
+
+void mqttSetup() {
+  mqtt.setServer("10.0.0.50", 1883);
+  mqtt.setBufferSize(512);
+}
+
+void mqttLoop() {
+  if (!isWiFiConnected()) {
+    mqtt.disconnect();
+  } else if (!mqtt.loop()) {
+    if (!mqtt.connect(WiFi.hostname().c_str())) {
+      mqtt.disconnect();
+    }
+  }
+}
+
+void mqttPublish(const char *topic, const char *payload) {
+  mqtt.publish(topic, payload);
+}
+
+String getLogPrefix(const char *level) {
+  tm info{};
+  getLocalTime(&info);
+  char buffer[20];
+  snprintf(buffer, sizeof buffer, "%04d-%02d-%02d %02d:%02d:%02d %5s ", info.tm_year, info.tm_mon, info.tm_mday, info.tm_hour, info.tm_min, info.tm_sec, level);
+  return {buffer};
+}
+
+void mqttLog(const char *level, const char *format, va_list vl) {
+  char message[400];
+  vsnprintf(message, sizeof message, format, vl);
+  const String topic = String("knx/log/") + level;
+  const String payload = getLogPrefix(level) + message;
+  mqttPublish(topic.c_str(), payload.c_str());
+}
+
+void mqttLogInfo(const char *message, ...) {
+  va_list vl;
+  va_start(vl, message);
+  mqttLog("info", message, vl);
+  va_end(vl);
+}
+
+void mqttLogError(const char *message, ...) {
+  va_list vl;
+  va_start(vl, message);
+  mqttLog("og/error", message, vl);
+  va_end(vl);
+}
diff --git a/src/mqtt.h b/src/mqtt.h
new file mode 100644
index 0000000..f73853c
--- /dev/null
+++ b/src/mqtt.h
@@ -0,0 +1,14 @@
+#ifndef MQTT_H
+#define MQTT_H
+
+void mqttSetup();
+
+void mqttLoop();
+
+void mqttPublish(const char *topic, const char *payload);
+
+void mqttLogInfo(const char *message, ...);
+
+void mqttLogError(const char *message, ...);
+
+#endif
diff --git a/src/time_.cpp b/src/time_.cpp
new file mode 100644
index 0000000..2d72104
--- /dev/null
+++ b/src/time_.cpp
@@ -0,0 +1,36 @@
+#include "time_.h"
+
+#include <Arduino.h>
+
+#define TIME_MIN                    1728424800
+
+bool hasTime = false;
+
+time_t timeCorrection = 0;
+
+void timeSetup() {
+  configTime("Europe/Berlin", "de.pool.ntp.org");
+}
+
+void timeLoop() {
+  if (hasTime) {
+    return;
+  }
+  const time_t now = time(nullptr);
+  if (now >= TIME_MIN) {
+    hasTime = true;
+    timeCorrection = now - timeCorrection;
+  } else {
+    timeCorrection = now;
+  }
+}
+
+bool isTimeSet() {
+  return hasTime;
+}
+
+void correctTime(time_t *t) {
+  if (*t > 0 && *t < TIME_MIN) {
+    *t += timeCorrection;
+  }
+}
diff --git a/src/time_.h b/src/time_.h
new file mode 100644
index 0000000..9cdfe56
--- /dev/null
+++ b/src/time_.h
@@ -0,0 +1,14 @@
+#ifndef MY_TIME_H
+#define MY_TIME_H
+
+#include <Arduino.h>
+
+void timeSetup();
+
+void timeLoop();
+
+bool isTimeSet();
+
+void correctTime(time_t *t);
+
+#endif
diff --git a/src/wifi.cpp b/src/wifi.cpp
new file mode 100644
index 0000000..399b1fa
--- /dev/null
+++ b/src/wifi.cpp
@@ -0,0 +1,45 @@
+#include "wifi.h"
+
+#include <ESP8266WiFi.h>
+
+#define WIFI_TIMEOUT_MILLIS         20000
+
+unsigned long wifiConnectBegin = 0;
+
+bool wifiConnected = false;
+
+bool isWiFiConnected() {
+  return wifiConnected;
+}
+
+void wifiSetup() {
+  wifiConnected = false;
+  WiFi.disconnect();
+  yield();
+
+  wifiConnectBegin = millis();
+  Serial.print("connecting wifi...\n");
+  WiFi.hostname("KnxEsp");
+  WiFi.begin("HappyNet", "1Grausame!Sackratte7");
+}
+
+void wifiLoop() {
+  if (!wifiConnected) {
+    if (WiFi.localIP() == 0UL) {
+      if (millis() - wifiConnectBegin > WIFI_TIMEOUT_MILLIS) {
+        if (wifiConnectBegin != 0) {
+          Serial.print("wifi timeout\n");
+        }
+        wifiSetup();
+      }
+    } else {
+      Serial.print("wifi connected\n");
+      wifiConnected = true;
+    }
+  } else {
+    if (WiFi.localIP() == 0UL) {
+      Serial.print("wifi disconnected\n");
+      wifiSetup();
+    }
+  }
+}
diff --git a/src/wifi.h b/src/wifi.h
new file mode 100644
index 0000000..4985adc
--- /dev/null
+++ b/src/wifi.h
@@ -0,0 +1,14 @@
+#ifndef WIFI_H
+#define WIFI_H
+
+bool isWiFiConnected();
+
+void wifiSetup();
+
+void wifiLoop();
+
+void timeLoop();
+
+bool isTimeSet();
+
+#endif