diff --git a/gateway/include/Protocol.h b/gateway/include/Protocol.h
index 9d966c9..056adc8 100644
--- a/gateway/include/Protocol.h
+++ b/gateway/include/Protocol.h
@@ -2,15 +2,24 @@
 #include <ArduinoJson.h>
 #include <RCSwitch.h>
 
+using namespace std;
+
 class Protocol {
 protected:
-    unsigned int protocol;
+    unsigned int no;
 
 public:
+    static unordered_map<unsigned int, Protocol*> mapProtocols;
+
     Protocol(unsigned int protocol) {
-        this->protocol = protocol;
+        no = protocol;
+        mapProtocols.insert({ no, this });
+    }
+
+    Protocol& setProtocol(unsigned int p) {
+        no = p;
+        return *this;
     }
-    virtual ~Protocol() {}
 
     virtual void fromJson(JsonObjectConst& rcSwitch, RCSwitch& rcDevice) {
         unsigned int protocol = rcSwitch["protocol"];
@@ -20,8 +29,9 @@ public:
 
     virtual void toJson(unsigned long value, JsonDocument& jsonDoc) {
         JsonObject rcSwitch = jsonDoc.createNestedObject("rcSwitch");
-        rcSwitch["protocol"] = protocol;
+        rcSwitch["protocol"] = no;
         rcSwitch["value"] = value;
     }
-
-};
\ No newline at end of file
+};
+unordered_map<unsigned int, Protocol*> Protocol::mapProtocols;
+Protocol fallbackProtocol{ 0 };
diff --git a/gateway/include/Protocol_1.h b/gateway/include/Protocol_1.h
index 6d9dd85..112104d 100644
--- a/gateway/include/Protocol_1.h
+++ b/gateway/include/Protocol_1.h
@@ -5,8 +5,7 @@
 class Protocol_1 : public Protocol {
 
 public:
-    Protocol_1() : Protocol(1) {
-    }
+    Protocol_1() : Protocol(1) {}
 
     void fromJson(JsonObjectConst& rcSwitch, RCSwitch& rcDevice) override {
         unsigned int protocol = rcSwitch["protocol"];
@@ -18,7 +17,7 @@ public:
 
     void toJson(unsigned long value, JsonDocument& jsonDoc) override {
         JsonObject rcSwitch = jsonDoc.createNestedObject("rcSwitch");
-        rcSwitch["protocol"] = protocol;
+        rcSwitch["protocol"] = no;
         RcDecoder decoder;
         decoder.decode(value);
         rcSwitch["state"] = decoder.state;
@@ -32,4 +31,4 @@ public:
         sprintf(uId, "%s_%d", group, channel);
         return std::string{ uId };
     }
-};
+} protocol1;
diff --git a/gateway/include/Protocol_2.h b/gateway/include/Protocol_2.h
index 589154e..9e780f2 100644
--- a/gateway/include/Protocol_2.h
+++ b/gateway/include/Protocol_2.h
@@ -5,8 +5,7 @@
 class Protocol_2 : public Protocol {
 
 public:
-    Protocol_2() : Protocol(2) {
-    }
+    Protocol_2() : Protocol(2) {}
 
     void toJson(unsigned long value, JsonDocument& jsonDoc) override {
         switch (value) {
@@ -33,4 +32,4 @@ public:
         }
     }
 
-};
\ No newline at end of file
+} protocol2;
\ No newline at end of file
diff --git a/gateway/include/Protocol_Doorbell.h b/gateway/include/Protocol_Doorbell.h
new file mode 100644
index 0000000..59285cf
--- /dev/null
+++ b/gateway/include/Protocol_Doorbell.h
@@ -0,0 +1,64 @@
+#pragma once
+#include "Protocol.h"
+
+#define BIT_LENGTH 40
+#define BIT_LENGTH_3 BIT_LENGTH*3
+#define TX_DELAY 620
+
+class Protocol_Doorbell : public Protocol {
+
+public:
+    Protocol_Doorbell() : Protocol(16) {}
+
+    void ring() {
+        preamble();
+        for (int i = 0; i < 7; i++) {
+            delayMicroseconds(TX_DELAY);
+            code("00000000110100101000100");
+        }
+    }
+
+    void fromJson(JsonObjectConst& rcSwitch, RCSwitch& rcDevice) override {
+    }
+
+    void toJson(unsigned long value, JsonDocument& jsonDoc) override {
+    }
+
+private:
+    void transmitBit(uint8_t value) {
+        digitalWrite(SEND_PIN, value);
+        delayMicroseconds(BIT_LENGTH);
+        digitalWrite(SEND_PIN, LOW);
+    }
+
+    void transmitHigh() {
+        digitalWrite(SEND_PIN, HIGH);
+        delayMicroseconds(BIT_LENGTH_3);
+        digitalWrite(SEND_PIN, LOW);
+        delayMicroseconds(BIT_LENGTH);
+    }
+
+    void transmitLow() {
+        digitalWrite(SEND_PIN, HIGH);
+        delayMicroseconds(BIT_LENGTH);
+        digitalWrite(SEND_PIN, LOW);
+        delayMicroseconds(BIT_LENGTH_3);
+    }
+
+    void preamble() {
+        noInterrupts();
+        for (int i = 0; i < 370; i++) {
+            transmitBit(HIGH);
+            transmitBit(LOW);
+        }
+        interrupts();
+    }
+
+    void code(const char* value) {
+        noInterrupts();
+        for (const char* p = value; *p; p++) {
+            *p == '1' ? transmitHigh() : transmitLow();
+        }
+        interrupts();
+    }
+} doorbell;
diff --git a/gateway/include/devices.h b/gateway/include/devices.h
index b59c9cb..4353af7 100644
--- a/gateway/include/devices.h
+++ b/gateway/include/devices.h
@@ -6,44 +6,50 @@
 
 using namespace Ha;
 
-DeviceConfig* gatewayDevice = (new DeviceConfig{MAIN_DEVICE_ID})->withName("RC Gateway")->withManufacturer("Adafruit")->withModel("Huzzah Esp8266");
+typedef unordered_multimap<unsigned long, Ha::Switch*> mapswitches;
+
+mapswitches onSwitches;
+mapswitches offSwitches;
+unordered_map<string, Ha::Switch*> p1Switches;
+
+auto gatewayDevice = &DeviceConfig::create(MAIN_DEVICE_ID).withName("RC Gateway").withManufacturer("Adafruit").withModel("Huzzah Esp8266");
 
 namespace OilTank {
     Sensor* buildRoomSensor(const char* id) {
-        auto device = DeviceConfig::create(id)
-            ->withName("Oil tank room")
-            ->withManufacturer("Atmel")
-            ->withModel("AtTiny85")
-            ->withArea("Basement")
-            ->withParent(gatewayDevice);
+        DeviceConfig* device = &DeviceConfig::create(id)
+            .withName("Oil tank room")
+            .withManufacturer("Atmel")
+            .withModel("AtTiny85")
+            .withArea("Basement")
+            .withParent(gatewayDevice);
         return Builder<TemperatureSensor>::instance(id)
             .asDevice(device)
             .withValueTemplate("{{ value_json.sensor.temperature }}")
-            .withDiagnostic(new VoltageSensor{id, "Battery voltage", "{{ value_json.sensor.diagnostic.voltage }}"})
-            .withDiagnostic(new BatterySensor{id, "Battery level", "{{ ((states('sensor.oil_tank_room_battery_voltage')|float-2.5)|round(2)*100/2)|int }}"})
+            .asDiagnostic(new VoltageSensor{id, "Battery voltage", "{{ value_json.sensor.diagnostic.voltage }}"})
+            .asDiagnostic(new BatterySensor{id, "Battery level", "{{ ((states('sensor.oil_tank_room_battery_voltage')|float-2.5)|round(2)*100/2)|int }}"})
             .build();
     }
 
     Sensor* buildTankSensor(const char* id) {
-        auto device = DeviceConfig::create(id)
-            ->withName("Oil tank")
-            ->withManufacturer("Arduino")
-            ->withModel("Pro Mini")
-            ->withArea("Basement")
-            ->withParent(gatewayDevice);
+        DeviceConfig* device = &DeviceConfig::create(id)
+            .withName("Oil tank")
+            .withManufacturer("Arduino")
+            .withModel("Pro Mini")
+            .withArea("Basement")
+            .withParent(gatewayDevice);
         return Builder<Sensor>::instance(new Sensor{ "Depth", id })
             .asDevice(device)
             .withDeviceClass("distance")
             .withUnitMseasure("cm")
             .withValueTemplate("{{ value_json.sensor.value }}")
-            .withSecondary(
+            .asSecondary(
                 Builder<Sensor>::instance(new Sensor{ "Level", id })
                 .withUnitMseasure("%")
                 .withValueTemplate("{{ 100 - ((value_json.sensor.value-7)|float*100/110)|round(2) }}")
                 .build()
             )
-            .withDiagnostic(new VoltageSensor{id, "Battery voltage", "{{ value_json.sensor.diagnostic.voltage }}"})
-            .withDiagnostic(new BatterySensor{id, "Battery level", "{{ ((states('sensor.oil_tank_battery_voltage')|float-3.6)|round(2)*100/1.6)|int }}"})
+            .asDiagnostic(new VoltageSensor{id, "Battery voltage", "{{ value_json.sensor.diagnostic.voltage }}"})
+            .asDiagnostic(new BatterySensor{id, "Battery level", "{{ ((states('sensor.oil_tank_battery_voltage')|float-3.6)|round(2)*100/1.6)|int }}"})
             .build();
     }
 }
@@ -60,7 +66,7 @@ struct PollinSwitch : Switch {
                 strcpy(uId, s.c_str());
                 return uId;
             }()), group(group), channel(channel) {
-        mainDevice = (new DeviceConfig{id})->withName(name)->withManufacturer("Pollin")->withArea(area)->withParent(gatewayDevice);
+        mainDevice = &DeviceConfig::create(id).withName(name).withManufacturer("Pollin").withArea(area).withParent(gatewayDevice);
         deviceClass = "outlet";
         p1Switches.insert({ string(id), this });
     }
@@ -80,7 +86,7 @@ struct EasyHomeSwitch : Switch {
         : Switch(name, id) {
         memcpy(&this->on[4], on, 4 * sizeof(unsigned long));
         memcpy(&this->off[4], off, 4 * sizeof(unsigned long));
-        mainDevice = (new DeviceConfig{id})->withName(name)->withManufacturer("Intertek")->withModel("Easy Home")->withArea(area)->withParent(gatewayDevice);
+        mainDevice = &DeviceConfig::create(id).withName(name).withManufacturer("Intertek").withModel("Easy Home").withArea(area).withParent(gatewayDevice);
         deviceClass = "outlet";
         for (int i = 0; i < 8; i++) {
             onSwitches.insert({ this->on[i], this });
@@ -101,6 +107,19 @@ Command* commands[] = {
             if (strcmp("PRESS", msg) == 0) ESP.restart();
         }
     }).asDevice(gatewayDevice).build(),
+    Builder<Button>::instance(new Button{"Front door", "doorbell_front",
+        [](const char* msg) {
+            if (strcmp("PRESS", msg) == 0) doorbell.ring();
+        }
+    })
+    .asDevice(
+        &DeviceConfig::create("doorbell")
+        .withName("Doorbell")
+        .withManufacturer("Thomson")
+        .withModel("Kinetic Halo")
+        .withParent(gatewayDevice)
+        )
+    .build(),
     (new EasyHomeSwitch{"FritzBox", "easy_home_a", (unsigned long[4]) { 4483136, 4626800, 4661552, 4819632 }, (unsigned long[4]) { 4326544, 4537104, 4767520, 4972704 }, "Basement"})->withStateTopic(),
     (new EasyHomeSwitch{"Outside", "easy_home_b", (unsigned long[4]) { 4483140, 4626804, 4661556, 4819636 }, (unsigned long[4]) { 4326548, 4537108, 4767524, 4972708 }, "Basement"})->withStateTopic(),
     (new PollinSwitch{"Meeting sensor", "00001", 1, "Dining room"})->withStateTopic(),
diff --git a/gateway/include/ha.h b/gateway/include/ha.h
index 26385c3..6a56af9 100644
--- a/gateway/include/ha.h
+++ b/gateway/include/ha.h
@@ -16,12 +16,10 @@ namespace Ha {
         const char* model = nullptr;
         const char* manufacturer = nullptr;
         const char* area = nullptr;
-        DeviceConfig* parent = nullptr;
+        const DeviceConfig* parent = nullptr;
 
-        DeviceConfig(const char* id) : id(id) {}
-
-        static DeviceConfig* create(const char* id) {
-            return new DeviceConfig{ id };
+        static DeviceConfig& create(const char* id) {
+            return *(new DeviceConfig{ id });
         }
 
         void buildConfig(JsonDocument& jsonDoc) {
@@ -35,30 +33,33 @@ namespace Ha {
             identifiers.add(id);
         }
 
-        DeviceConfig* withName(const char* value) {
+        DeviceConfig& withName(const char* value) {
             name = value;
-            return this;
+            return *this;
         }
 
-        DeviceConfig* withModel(const char* value) {
+        DeviceConfig& withModel(const char* value) {
             model = value;
-            return this;
+            return *this;
         }
 
-        DeviceConfig* withManufacturer(const char* value) {
+        DeviceConfig& withManufacturer(const char* value) {
             manufacturer = value;
-            return this;
+            return *this;
         }
 
-        DeviceConfig* withArea(const char* value) {
+        DeviceConfig& withArea(const char* value) {
             area = value;
-            return this;
+            return *this;
         }
 
-        DeviceConfig* withParent(DeviceConfig* deviceConfig) {
+        DeviceConfig& withParent(const DeviceConfig* deviceConfig) {
             parent = deviceConfig;
-            return this;
+            return *this;
         }
+
+    protected:
+        DeviceConfig(const char* id) : id(id) {}
     };
 
     struct Component {
@@ -108,7 +109,6 @@ namespace Ha {
             publisher(configTopic, "");
         }
     };
-    List<Component> Component::components;
 
     struct AbstractBuilder {
         static List<AbstractBuilder> builders;
@@ -122,7 +122,6 @@ namespace Ha {
             builders.empty();
         }
     };
-    List<AbstractBuilder> AbstractBuilder::builders;
 
     template <class T>
     struct Builder : AbstractBuilder {
@@ -161,15 +160,14 @@ namespace Ha {
             return *this;
         }
 
-        Builder& withSecondary(Component* c) {
-            c->mainDevice = new DeviceConfig{ cmp->id };
+        Builder& asSecondary(Component* c) {
+            c->mainDevice = &DeviceConfig::create(cmp->id);
             return *this;
         }
 
-        Builder& withDiagnostic(Component* c) {
+        Builder& asDiagnostic(Component* c) {
             c->entityCategory = "diagnostic";
-            c->mainDevice = new DeviceConfig{ cmp->id };
-            return *this;
+            return asSecondary(c);
         }
 
         Builder& asDevice(DeviceConfig* deviceConfig) {
@@ -198,7 +196,6 @@ namespace Ha {
         }
 
     };
-    unordered_map<string, Command*> Command::mapCommands;
 
     struct Button : Command {
 
@@ -227,7 +224,7 @@ namespace Ha {
             if (stateTopic[0]) jsonDoc["state_topic"] = stateTopic;
         }
 
-        void publishState(bool state) {
+        void updateState(bool state) {
             publisher(stateTopic, state ? "ON" : "OFF");
         }
     };
@@ -235,13 +232,11 @@ namespace Ha {
     struct Sensor : Component, StateConfig<Sensor> {
         const char* unitMeasure = nullptr;
         const char* valueTemplate = nullptr;
-
-        Sensor() : Component(name, id, "sensor") {
-            withStateTopic();
-        }
+        static unordered_map<string, Sensor*> mapSensors;
 
         Sensor(const char* name, const char* id) : Component(name, id, "sensor") {
             withStateTopic();
+            mapSensors.insert({ id, this });
         }
 
         void buildUniqueId(char* uniqueId) override {
@@ -267,6 +262,10 @@ namespace Ha {
             jsonDoc["state_topic"] = stateTopic;
             jsonDoc["suggested_display_precision"] = 2;
         }
+
+        void updateState(const char* message) {
+            publisher(stateTopic, message);
+        }
     };
 
     struct TemperatureSensor : Sensor {
@@ -307,4 +306,9 @@ namespace Ha {
             // valueTemplate = "{{ value_json.sensor.pressure }}";
         }
     };
+
+    List<Component> Component::components;
+    List<AbstractBuilder> AbstractBuilder::builders;
+    unordered_map<string, Command*> Command::mapCommands;
+    unordered_map<string, Sensor*> Sensor::mapSensors;
 }
diff --git a/gateway/include/huzzah.h b/gateway/include/huzzah.h
index 03b855e..69c82aa 100644
--- a/gateway/include/huzzah.h
+++ b/gateway/include/huzzah.h
@@ -1,22 +1,9 @@
 #include <TaskScheduler.h>
 
-#define SEND_PIN 14                                  
-#define RECEIVE_PIN 12
-#define RED_LED LED_BUILTIN
-#define BLUE_LED 2
-
 using namespace std;
 
 Scheduler ts;
 
-namespace Ha {
-    struct Switch;
-}
-typedef unordered_multimap<unsigned long, Ha::Switch*> mapswitches;
-mapswitches onSwitches;
-mapswitches offSwitches;
-unordered_map<string, Ha::Switch*> p1Switches;
-
 void turnLed(uint8_t led, bool on = true) {
 	on ? digitalWrite(led, LOW) : digitalWrite(led, HIGH);
 }
@@ -57,7 +44,7 @@ namespace Board {
 		case 1: {
 			string id = Protocol_1::buildId((const char*)rcSwitch["group"], (int)rcSwitch["channel"]);
 			Ha::Switch* el = p1Switches[id];
-			if (el) el->publishState((bool)rcSwitch["state"]);
+			if (el) el->updateState((bool)rcSwitch["state"]);
 			break;
 		}
 		case 2:
@@ -66,11 +53,11 @@ namespace Board {
 			unsigned long value = rcSwitch["value"];
 			auto range = onSwitches.equal_range(value);
 			for_each(range.first, range.second, [](mapswitches::value_type& x){
-				x.second->publishState(true);
+				x.second->updateState(true);
 			});
 			range = offSwitches.equal_range(value);
 			for_each(range.first, range.second, [](mapswitches::value_type& x){
-				x.second->publishState(false);
+				x.second->updateState(false);
 			});
 		}
 		}
@@ -79,10 +66,8 @@ namespace Board {
 	void parseSensors(JsonDocument& jsonDoc, char* message) {
 		JsonObjectConst json = jsonDoc["sensor"];
 		string id = to_string((unsigned int)json["id"]);
-		char stateTopic[TOPIC_SIZE];
-		sprintf(stateTopic, "homeassistant/sensor/%s/%s/state", MAIN_DEVICE_ID, id.c_str());
-		Mqtt::publish(stateTopic, message);
-
+		auto sensor = Sensor::mapSensors[id];
+		if (sensor) sensor->updateState(message);
 	}
 
 	void publishResponse(JsonDocument& jsonDoc) {
diff --git a/gateway/include/pins.h b/gateway/include/pins.h
new file mode 100644
index 0000000..728511f
--- /dev/null
+++ b/gateway/include/pins.h
@@ -0,0 +1,12 @@
+#pragma once
+
+#if defined(ESP8266)
+#define SEND_PIN 14
+#define RECEIVE_PIN 12
+#define RED_LED LED_BUILTIN
+#define BLUE_LED 2
+#else
+#define RESET_PIN 10
+#define SEND_PIN 11
+#define RECEIVE_PIN 2
+#endif
diff --git a/gateway/include/pro-mini.h b/gateway/include/pro-mini.h
index fed8722..b43e076 100644
--- a/gateway/include/pro-mini.h
+++ b/gateway/include/pro-mini.h
@@ -1,9 +1,5 @@
 #include "output.h"
 
-#define RESET_PIN 10
-#define SEND_PIN 11
-#define RECEIVE_PIN 2
-
 namespace Board {
 	
 	void setup() {
diff --git a/gateway/src/gateway.cpp b/gateway/src/gateway.cpp
index cdafa1d..a3714a4 100644
--- a/gateway/src/gateway.cpp
+++ b/gateway/src/gateway.cpp
@@ -1,9 +1,11 @@
 #include <Arduino.h>
 #include <RCSwitch.h>
 #include <SerialReader.h>
+#include "pins.h"
 #include "Dht.h"
 #include "Protocol_1.h"
 #include "Protocol_2.h"
+#include "Protocol_Doorbell.h"
 
 RCSwitch mySwitch;
 SerialReader<200> serialReader;
@@ -29,15 +31,9 @@ void setup() {
 	delay(1000);
 }
 
-Protocol* findProtocol(unsigned int protocol) {
-	switch (protocol) {
-	case 1:
-		return new Protocol_1();
-	case 2:
-		return new Protocol_2();
-	default:
-		return new Protocol(protocol);
-	}
+Protocol& findProtocol(unsigned int protocol) {
+	auto p = Protocol::mapProtocols[protocol];
+	return p ? *p : fallbackProtocol.setProtocol(protocol);
 }
 
 void readRcSwitch() {
@@ -52,9 +48,8 @@ void readRcSwitch() {
 		mySwitch.resetAvailable();
 
 		StaticJsonDocument<128> jsonDoc;
-		Protocol* p = findProtocol(mySwitch.getReceivedProtocol());
-		p->toJson(value, jsonDoc);
-		delete p;
+		Protocol& p = findProtocol(mySwitch.getReceivedProtocol());
+		p.toJson(value, jsonDoc);
 		if (!jsonDoc.isNull()) {
 			serializeJson(jsonDoc, Serial);
 			Serial.println();
@@ -75,14 +70,13 @@ void handleJsonError(DeserializationError err, const char* cmd) {
 }
 
 void runJsonCommand(char* cmd) {
-	StaticJsonDocument<50> jsonDoc;
+	StaticJsonDocument<128> jsonDoc;
 	DeserializationError err = deserializeJson(jsonDoc, cmd);
 	if (err == DeserializationError::Ok) {
 		if (jsonDoc.containsKey("rcSwitch")) {
 			JsonObjectConst rcSwitch = jsonDoc["rcSwitch"];
-			Protocol* p = findProtocol(rcSwitch["protocol"]);
-			p->fromJson(rcSwitch, mySwitch);
-			delete p;
+			Protocol& p = findProtocol(rcSwitch["protocol"]);
+			p.fromJson(rcSwitch, mySwitch);
 			serializeJson(jsonDoc, Serial);
 			Serial.println();
 			Board::publishResponse(jsonDoc);