diff --git a/src/App/App.cpp b/src/App/App.cpp
index 4dae346..a0f86a3 100644
--- a/src/App/App.cpp
+++ b/src/App/App.cpp
@@ -11,28 +11,19 @@ namespace Dough
     App::App() : config(),
                  ui(),
                  wifi(),
-                 mqtt(
-                     &wifi,
-                     mqttOnConnectCallback,
-                     mqttOnMessageCallback),
+                 mqtt(&wifi, mqttOnConnectCallback, mqttOnMessageCallback),
                  temperatureSensor(
-                     &mqtt,
-                     "temperature",
-                     TemperatureSensor::Instance(),
+                     &mqtt, "temperature", TemperatureSensor::Instance(),
                      TEMPERATURE_AVERAGE_STORAGE,
                      TEMPERATURE_MEASURE_INTERVAL, sensorOnMeasureCallback,
                      MINIMUM_PUBLISH_INTERVAL, sensorOnPublishCallback),
                  humiditySensor(
-                     &mqtt,
-                     "humidity",
-                     HumiditySensor::Instance(),
+                     &mqtt, "humidity", HumiditySensor::Instance(),
                      HUMIDITY_AVERAGE_STORAGE,
                      HUMIDITY_MEASURE_INTERVAL, sensorOnMeasureCallback,
                      MINIMUM_PUBLISH_INTERVAL, sensorOnPublishCallback),
                  distanceSensor(
-                     &mqtt,
-                     "distance",
-                     DistanceSensor::Instance(),
+                     &mqtt, "distance", DistanceSensor::Instance(),
                      DISTANCE_AVERAGE_STORAGE,
                      DISTANCE_MEASURE_INTERVAL, sensorOnMeasureCallback,
                      MINIMUM_PUBLISH_INTERVAL, sensorOnPublishCallback),
diff --git a/src/App/App.h b/src/App/App.h
index 709318f..ed50aac 100644
--- a/src/App/App.h
+++ b/src/App/App.h
@@ -2,6 +2,7 @@
 #define DOUGH_APP_H
 
 #include <Arduino.h>
+#include "UI/UI.h"
 #include "App/Configuration.h"
 #include "Data/SensorController.h"
 #include "Sensors/TemperatureSensor.h"
diff --git a/src/Data/SensorController.h b/src/Data/SensorController.h
index 316790c..962f145 100644
--- a/src/Data/SensorController.h
+++ b/src/Data/SensorController.h
@@ -5,7 +5,6 @@
 #include "Sensors/SensorBase.h"
 #include "Data/Measurement.h"
 #include "Network/MQTT.h"
-#include "UI/UI.h"
 
 namespace Dough
 {
diff --git a/src/UI/UI.cpp b/src/UI/UI.cpp
index 4afbd18..9be1dfe 100644
--- a/src/UI/UI.cpp
+++ b/src/UI/UI.cpp
@@ -4,10 +4,10 @@ namespace Dough
 {
     UI::UI() : onoffButton(ONOFF_BUTTON_PIN),
                setupButton(SETUP_BUTTON_PIN),
-               ledBuiltin(LED_BUILTIN),
-               led1(LED1_PIN),
-               led2(LED2_PIN),
-               led3(LED3_PIN) {}
+               _ledBuiltin(LED_BUILTIN),
+               _led1(LED1_PIN),
+               _led2(LED2_PIN),
+               _led3(LED3_PIN) {}
 
     void UI::setup()
     {
@@ -16,10 +16,10 @@ namespace Dough
         setupButton.setup();
 
         // Setup the LEDs.
-        ledBuiltin.setup();
-        led1.setup();
-        led2.setup();
-        led3.setup();
+        _ledBuiltin.setup();
+        _led1.setup();
+        _led2.setup();
+        _led3.setup();
 
         // Setup a timer interrupt that is used to update the
         // user interface (a.k.a. "LEDs") in parallel to other activities.
@@ -104,66 +104,73 @@ namespace Dough
     // something else.
     void UI::updateLEDs()
     {
-        ledBuiltin.loop();
-        led1.loop();
-        led2.loop();
-        led3.loop();
+        _ledBuiltin.loop();
+        _led1.loop();
+        _led2.loop();
+        _led3.loop();
     }
 
     void UI::notifyConnectingToWifi()
     {
-        led1.blink()->slow();
-        led2.off();
-        led3.off();
+        _led1.blink()->slow();
+        _led2.off();
+        _led3.off();
     }
     
     void UI::notifyConnectingToMQTT()
     {
-        led1.blink()->fast();
-        led2.off();
-        led3.off();
+        _led1.blink()->fast();
+        _led2.off();
+        _led3.off();
+    }
+
+    void UI::notifyConnected()
+    {
+        _led1.on();
+        _led2.off();
+        _led3.off();
     }
 
     void UI::notifyWaitingForConfiguration()
     {
-        led1.on();
-        led2.blink()->slow();
-        led3.off();
+        _led1.on();
+        _led2.blink()->slow();
+        _led3.off();
     }
 
     void UI::notifyCalibrating()
     {
-        led1.on();
-        led2.blink()->fast();
-        led3.off();
+        _led1.on();
+        _led2.blink()->fast();
+        _led3.off();
     }
 
     void UI::notifyMeasurementsActive()
     {
-        led1.on();
-        led2.on();
-        led3.on();
+        _led1.on();
+        _led2.on();
+        _led3.on();
     }
 
     void UI::notifyMeasurementsPaused()
     {
-        led1.on();
-        led2.on();
-        led3.pulse();
+        _led1.on();
+        _led2.on();
+        _led3.pulse();
     }
 
     void UI::notifySensorActivity()
     {
-        led3.off();
+        _led3.off();
         delay(50);
-        led3.on();        
+        _led3.on();        
     }
 
     void UI::notifyNetworkActivity()
     {
-        led1.off();
+        _led1.off();
         delay(50);
-        led1.on();        
+        _led1.on();        
     }
     
     // Flash all LEDs, one at a time in a synchroneous manner, making
@@ -171,17 +178,17 @@ namespace Dough
     // as a "Hey, I'm awake!" signal from the device after booting up.
     void UI::_flash_all_leds()
     {
-        ledBuiltin.on();
+        _ledBuiltin.on();
         delay(100);
-        ledBuiltin.off();
-        led1.on();
+        _ledBuiltin.off();
+        _led1.on();
         delay(100);
-        led1.off();
-        led2.on();
+        _led1.off();
+        _led2.on();
         delay(100);
-        led2.off();
-        led3.on();
+        _led2.off();
+        _led3.on();
         delay(100);
-        led3.off();
+        _led3.off();
     }
 } // namespace Dough
\ No newline at end of file
diff --git a/src/UI/UI.h b/src/UI/UI.h
index bfb9bd4..033a91a 100644
--- a/src/UI/UI.h
+++ b/src/UI/UI.h
@@ -20,10 +20,6 @@ namespace Dough
         static void setupButtonISR();
         Button onoffButton;
         Button setupButton;
-        LED ledBuiltin;
-        LED led1;
-        LED led2;
-        LED led3;
         void processButtonEvents();
         void clearButtonEvents();
         void updateLEDs();
@@ -31,6 +27,7 @@ namespace Dough
         void suspend();
         void notifyConnectingToWifi();
         void notifyConnectingToMQTT();
+        void notifyConnected();
         void notifyWaitingForConfiguration();
         void notifyCalibrating();
         void notifyMeasurementsActive();
@@ -39,6 +36,10 @@ namespace Dough
         void notifyNetworkActivity();
 
     private:
+        LED _ledBuiltin;
+        LED _led1;
+        LED _led2;
+        LED _led3;
         void _setupTimerInterrupt();
         static UI *_instance;
         void _flash_all_leds();
diff --git a/src/main.cpp b/src/main.cpp
index da71482..bf689f6 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,7 +1,7 @@
 #include "main.h"
 
 // TOOD: implement the calibration logic
-// TODO: don't make sensors instances
+// TODO: don't make sensors instances anymore, now they are handled by App as the only singleton
 // TODO: see what more stuff can be moved to the UI code. Maybe state to UI state translation ought to be there as well
 
 DoughBoyState state = CONFIGURING;