diff --git a/main/CMakeLists.txt b/main/CMakeLists.txt
index 84078a2..54fa613 100644
--- a/main/CMakeLists.txt
+++ b/main/CMakeLists.txt
@@ -5,6 +5,7 @@ idf_component_register(
             "http_serv.cpp"
             "ota.cpp"
             "mqtt.cpp"
+            "device.cpp"
 
         INCLUDE_DIRS "."
     )
diff --git a/main/device.cpp b/main/device.cpp
new file mode 100644
index 0000000..03d4893
--- /dev/null
+++ b/main/device.cpp
@@ -0,0 +1,76 @@
+static const char *TAG = "device";
+#include <esp_log.h>
+
+#include "device.hpp"
+
+
+Device::Device(std::string _id) :
+            id(_id),
+            state_topic("light/" + id + "/state"),
+            cmd_topic("light/" + id + "/cmd"),
+            ready(false), should_publish(false),
+            mutex(xSemaphoreCreateMutex()),
+            sem(xSemaphoreCreateBinary()),
+            power_on(true),
+            client(start_mqtt_client(on_mqtt_connect, on_mqtt_message, this))
+        {}
+    
+void Device::set_mqtt_config(cJSON*) {
+    xSemaphoreTake(mutex, portMAX_DELAY);
+
+    // TODO: update power_on and effect from JSON
+    publish_state_locked();
+
+    xSemaphoreGive(mutex);
+}
+
+void Device::on_mqtt_connect(esp_mqtt_client_handle_t client) {
+    xSemaphoreTake(mutex, portMAX_DELAY);
+
+    ESP_LOGI(TAG, "Connected to MQTT");
+
+    if (esp_mqtt_client_subscribe(client, cmd_topic.c_str(), 0) < 0) {
+        ESP_LOGE(TAG, "Failed to subscribe to %s", cmd_topic.c_str());
+    }
+    if (0 > esp_mqtt_client_publish(
+                client,
+                ("homeassistant/light/" + id + "/config").c_str(),
+                ("{"
+                    "\"unique_id\": \"" + id + "\", "
+                    "\"device\": {\"name\": \"blinky_" + id + "\"}, "
+                    "\"state_topic\": \"" + state_topic + "\", "
+                    "\"command_topic\": \"" + cmd_topic + "\", "
+                    "\"schema\": \"json\", "
+                    "\"effect\": True, "
+                    "\"effect_list\": [\"dummy\"]"
+                 "}").c_str(), 0,
+                0, 0
+            )) {
+        ESP_LOGE(TAG, "Failed to publish discovery message");
+    }
+
+    ready = true;
+    if (should_publish) publish_state_locked();
+
+    xSemaphoreGive(mutex);
+}
+
+void Device::on_mqtt_message(esp_mqtt_client_handle_t, esp_mqtt_event_handle_t) {
+    ESP_LOGI(TAG, "Received command via MQTT");
+    // TODO: extract JSON, call set_mqtt_config
+    xSemaphoreGive(sem);
+}
+
+void Device::publish_state_locked() {
+    if (!(should_publish = !ready)) {
+        ESP_ERROR_CHECK(esp_mqtt_client_publish(
+                client,
+                state_topic.c_str(),
+                ("{"
+                    "\"state\": \"" + std::string(power_on ? "ON" : "OFF") + "\", "
+                    "\"effect\": \"" + effect + "\""
+                 "}").c_str(), 0,
+                0, 0
+            ));
+    }
+}
\ No newline at end of file
diff --git a/main/device.hpp b/main/device.hpp
new file mode 100644
index 0000000..38b0641
--- /dev/null
+++ b/main/device.hpp
@@ -0,0 +1,57 @@
+#pragma once
+
+#include <string>
+
+#include <cJSON.h>
+
+#include "mqtt.hpp"
+
+
+class Device {
+public:
+    Device(std::string id);
+    
+    void set_mqtt_config(cJSON*);
+
+    void lock() const { xSemaphoreTake(mutex, portMAX_DELAY); }
+    void unlock() const { xSemaphoreGive(mutex); }
+
+    bool wait(int timeout_ms = -1) const {
+        return pdTRUE == xSemaphoreTake(
+                sem,
+                (timeout_ms < 0 ? portMAX_DELAY : pdMS_TO_TICKS(timeout_ms))
+            );
+    }
+
+    // Only call while locked
+    const std::string& get_effect() const { return effect; }
+    bool is_on() const { return power_on; }
+
+private:
+    std::string id;
+
+    std::string state_topic;
+    std::string cmd_topic;
+
+    bool ready, should_publish;
+
+    SemaphoreHandle_t mutex;
+    SemaphoreHandle_t sem;
+
+    bool power_on;
+    std::string effect;
+
+    esp_mqtt_client_handle_t client;
+
+    static void on_mqtt_connect(esp_mqtt_client_handle_t client, void* data) {
+        ((Device*)data)->on_mqtt_connect(client);
+    }
+    static void on_mqtt_message(esp_mqtt_client_handle_t client, esp_mqtt_event_handle_t event, void* data) {
+        ((Device*)data)->on_mqtt_message(client, event);
+    }
+
+    void on_mqtt_connect(esp_mqtt_client_handle_t);
+    void on_mqtt_message(esp_mqtt_client_handle_t, esp_mqtt_event_handle_t);
+
+    void publish_state_locked();
+};
\ No newline at end of file
diff --git a/main/main.cpp b/main/main.cpp
index 7fb5559..0b8d291 100644
--- a/main/main.cpp
+++ b/main/main.cpp
@@ -10,7 +10,7 @@ static const char *TAG = "blinky";
 #include "wifi.hpp"
 #include "http_serv.hpp"
 #include "ota.hpp"
-#include "mqtt.hpp"
+#include "device.hpp"
 
 
 // mDNS / NetBIOS
@@ -80,6 +80,13 @@ static void log_dir(const std::string &path) {
 }
 
 
+int64_t now_us() {
+    struct timeval tv_now;
+    gettimeofday(&tv_now, NULL);
+    return (int64_t)tv_now.tv_sec * 1000000L + (int64_t)tv_now.tv_usec;
+}
+
+
 // Entry Point
 
 extern "C" void app_main(void) {
@@ -108,8 +115,23 @@ extern "C" void app_main(void) {
     log_dir("/spiffs");
 
     // TODO: Something useful
-    esp_mqtt_client_handle_t client = start_mqtt_client(NULL, NULL, NULL);
-    esp_mqtt_client_subscribe(client, "#", 0);
+    Device device("blinky-jr");
+
+/*
+    int period_us = 1000000;
+    int64_t target_us = now_us();
+    while (true) {
+        int64_t delay_us = target_us - now_us();
+        if (delay_us < 0) delay_us = 0;
+        if (device.wait(delay_us / 1000))
+            ESP_LOGI(TAG, "Reload!");
+        else {
+            ESP_LOGI(TAG, "Timeout!");
+            target_us += period_us;
+        }
+    }
+*/
+    while (device.wait()) ESP_LOGI(TAG, "Reload!");
 
     // Spin
 }