diff --git a/.vscode/settings.json b/.vscode/settings.json
index 16dbf64..8e0afaf 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -21,6 +21,7 @@
     "*.wxs": "javascript",
     "*.inc": "c",
     "*.tcc": "c",
-    "*.ipp": "c"
+    "*.ipp": "c",
+    "cstring": "cpp"
   }
 }
diff --git a/main/CMakeLists.txt b/main/CMakeLists.txt
index d717f27..11efc7b 100644
--- a/main/CMakeLists.txt
+++ b/main/CMakeLists.txt
@@ -1,2 +1,2 @@
-idf_component_register(SRCS "main.c" "wifi.c" "light.c"
+idf_component_register(SRCS "mqtt.c" "main.c" "wifi.c" "light.c" "mqtt.c"
                     INCLUDE_DIRS ".")
\ No newline at end of file
diff --git a/main/light.c b/main/light.c
index 431da5c..f6e5b3b 100644
--- a/main/light.c
+++ b/main/light.c
@@ -24,6 +24,9 @@ typedef enum light_mode_e {
   light_mode_init = 0,
   light_mode_connection_wifi = 1,
   light_mode_idle = 2,
+  light_mode_mqtt_connected = 3,
+  light_mode_desktop_online = 4,
+  light_mode_desktop_sending_colors = 5,
 } light_mode_t;
 
 led_strip_t *light_led_strip;
@@ -82,6 +85,43 @@ void led_strip_hsv2rgb(uint32_t h, uint32_t s, uint32_t v, uint32_t *r,
   }
 }
 
+void update_desktop_connection_state() {
+  static uint8_t tick = 0;
+
+  uint8_t mask = tick / 10 % 2 ? 0xff : 0x00;
+
+  switch (light_mode) {
+    case light_mode_desktop_online:
+      ESP_ERROR_CHECK(light_led_strip->set_pixel(light_led_strip, 0, mask & 150,
+                                                 mask & 50, mask & 0));
+      ESP_ERROR_CHECK(
+          light_led_strip->set_pixel(light_led_strip, 1, 30, 100, 0));
+      ESP_ERROR_CHECK(
+          light_led_strip->set_pixel(light_led_strip, 2, 30, 100, 0));
+      break;
+    case light_mode_mqtt_connected:
+      ESP_ERROR_CHECK(light_led_strip->set_pixel(light_led_strip, 0, mask & 100,
+                                                 mask & 30, mask & 0));
+      ESP_ERROR_CHECK(light_led_strip->set_pixel(light_led_strip, 1, mask & 100,
+                                                 mask & 30, mask & 0));
+      ESP_ERROR_CHECK(
+          light_led_strip->set_pixel(light_led_strip, 2, 50, 150, 0));
+      break;
+    case light_mode_idle:
+      ESP_ERROR_CHECK(light_led_strip->set_pixel(light_led_strip, 0, mask & 100,
+                                                 mask & 30, mask & 0));
+      ESP_ERROR_CHECK(light_led_strip->set_pixel(light_led_strip, 1, mask & 100,
+                                                 mask & 30, mask & 0));
+      ESP_ERROR_CHECK(light_led_strip->set_pixel(light_led_strip, 2, mask & 100,
+                                                 mask & 30, mask & 0));
+      break;
+    default:
+      break;
+  }
+
+  tick++;
+}
+
 void light_for_init() {
   ESP_LOGI(LIGHT_TAG, "light_for_init");
   ESP_ERROR_CHECK(light_led_strip->clear(light_led_strip, 100));
@@ -113,7 +153,6 @@ void light_for_connecting_wifi() {
     ESP_ERROR_CHECK(light_led_strip->set_pixel(light_led_strip,
                                                (tick_tock + 1) % 2, 0, 200, 0));
     ESP_ERROR_CHECK(light_led_strip->refresh(light_led_strip, 100));
-    ESP_LOGI(LIGHT_TAG, "tick_tock %d", tick_tock);
     tick_tock = !tick_tock;
     vTaskDelay(pdMS_TO_TICKS(200));
   } while (light_mode == light_mode_connection_wifi);
@@ -126,7 +165,9 @@ void light_for_idle() {
   uint32_t red = 0, green = 0, blue = 0;
   uint16_t step_length = 360 / STRIP_LED_NUMBER;
 
-  for (uint16_t offset = 0; light_mode == light_mode_idle;
+  for (uint16_t offset = 0; light_mode == light_mode_idle ||
+                            light_mode == light_mode_mqtt_connected ||
+                            light_mode == light_mode_desktop_online;
        offset = (offset + 1) % 360) {
     for (uint16_t j = 0, hue = offset; j < STRIP_LED_NUMBER;
          j++, hue += step_length) {
@@ -136,6 +177,7 @@ void light_for_idle() {
       ESP_ERROR_CHECK(
           light_led_strip->set_pixel(light_led_strip, j, red, green, blue));
     }
+    update_desktop_connection_state();
     ESP_ERROR_CHECK(light_led_strip->refresh(light_led_strip, 100));
     vTaskDelay(pdMS_TO_TICKS(10));
   }
@@ -147,7 +189,7 @@ void light_strip_running_task(void *pv_parameters) {
       ESP_LOGE(LIGHT_TAG, "install WS2812 driver failed 2");
     }
     // Show simple rainbow chasing pattern
-    ESP_LOGI(LIGHT_TAG, "light_strip_running_task");
+    ESP_LOGI(LIGHT_TAG, "light_strip_running_task: %d", light_mode);
     switch (light_mode) {
       case light_mode_init:
         light_for_init();
@@ -156,9 +198,12 @@ void light_strip_running_task(void *pv_parameters) {
         light_for_connecting_wifi();
         break;
       case light_mode_idle:
+      case light_mode_mqtt_connected:
+      case light_mode_desktop_online:
         light_for_idle();
         break;
       default:
+        vTaskDelay(pdMS_TO_TICKS(100));
         break;
     }
   }
@@ -191,4 +236,7 @@ void light_init_strip() {
               1, NULL);
 }
 
-void light_play(light_mode_t mode) { light_mode = mode; }
\ No newline at end of file
+void light_play(light_mode_t mode) {
+  ESP_LOGI(LIGHT_TAG, "light_play: %d", mode);
+  light_mode = mode;
+}
\ No newline at end of file
diff --git a/main/main.c b/main/main.c
index 59e77cb..6a9a768 100644
--- a/main/main.c
+++ b/main/main.c
@@ -2,6 +2,7 @@
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
 #include "light.c"
+#include "mqtt.c"
 #include "sdkconfig.h"
 #include "wifi.c"
 
@@ -14,4 +15,15 @@ void app_main(void) {
   if (connect_wifi()) {
     light_play(light_mode_idle);
   }
+  vTaskDelay(pdMS_TO_TICKS(1000));
+  mqtt_app_start();
+  if (waiting_for_mqtt_connected()) {
+    light_play(light_mode_mqtt_connected);
+  }
+  if (waiting_for_desktop_online()) {
+    light_play(light_mode_desktop_online);
+  }
+  if (waiting_for_desktop_sending_colors()) {
+    light_play(light_mode_desktop_sending_colors);
+  }
 }
diff --git a/main/mqtt.c b/main/mqtt.c
new file mode 100644
index 0000000..b94e2ed
--- /dev/null
+++ b/main/mqtt.c
@@ -0,0 +1,159 @@
+#include <stdio.h>
+#include <string.h>
+
+#include "esp_bit_defs.h"
+#include "esp_event.h"
+#include "esp_log.h"
+#include "esp_system.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/event_groups.h"
+#include "freertos/queue.h"
+#include "freertos/semphr.h"
+#include "freertos/task.h"
+#include "mqtt_client.h"
+
+#define MQTT_FAILED_BIT BIT0
+#define MQTT_CONNECTED_BIT BIT1
+#define MQTT_DISCONNECTED_BIT BIT2
+#define MQTT_DESKTOP_ONLINE_BIT BIT3
+#define MQTT_DESKTOP_OFFLINE_BIT BIT4
+#define MQTT_DESKTOP_SENDING_BIT BIT5
+
+#define MQTT_BOARD_KEY_PREFIX "screen-bg-light/board/"
+#define MQTT_DESKTOP_KEY_PREFIX "screen-bg-light/desktop/"
+#define MQTT_ONLINE_SUFFIX "online"
+#define MQTT_COLORS_SUFFIX "colors"
+#define MQTT_ALL_SUFFIX "#"
+
+#define MQTT_KEY_BOARD_ONLINE MQTT_BOARD_KEY_PREFIX MQTT_ONLINE_SUFFIX
+#define MQTT_KEY_DESKTOP_ONLINE MQTT_DESKTOP_KEY_PREFIX MQTT_ONLINE_SUFFIX
+#define MQTT_KEY_DESKTOP_COLORS MQTT_DESKTOP_KEY_PREFIX MQTT_COLORS_SUFFIX
+#define MQTT_KEY_DESKTOP_ALL MQTT_DESKTOP_KEY_PREFIX MQTT_ALL_SUFFIX
+
+static const char *MQTT_TAG = "ScreenBgLight_MQTT";
+
+static EventGroupHandle_t s_mqtt_event_group;
+
+static void log_error_if_nonzero(const char *message, int error_code) {
+  if (error_code != 0) {
+    ESP_LOGE(MQTT_TAG, "Last error %s: 0x%x", message, error_code);
+  }
+}
+
+static void mqtt_event_handler(void *handler_args, esp_event_base_t base,
+                               int32_t event_id, void *event_data) {
+  ESP_LOGD(MQTT_TAG, "Event dispatched from event loop base=%s, event_id=%d",
+           base, event_id);
+  esp_mqtt_event_handle_t event = event_data;
+  esp_mqtt_client_handle_t client = event->client;
+  int msg_id;
+  switch ((esp_mqtt_event_id_t)event_id) {
+    case MQTT_EVENT_CONNECTED:
+      ESP_LOGI(MQTT_TAG, "MQTT_EVENT_CONNECTED");
+      xEventGroupSetBits(s_mqtt_event_group, MQTT_CONNECTED_BIT);
+      msg_id = esp_mqtt_client_publish(client, MQTT_KEY_BOARD_ONLINE, "ONLINE",
+                                       0, 1, 0);
+      ESP_LOGI(MQTT_TAG, "sent publish successful, msg_id=%d", msg_id);
+      esp_mqtt_client_subscribe(client, MQTT_KEY_DESKTOP_ALL, 0);
+      break;
+    case MQTT_EVENT_DISCONNECTED:
+      ESP_LOGI(MQTT_TAG, "MQTT_EVENT_DISCONNECTED");
+      xEventGroupSetBits(s_mqtt_event_group, MQTT_DISCONNECTED_BIT);
+      break;
+
+    case MQTT_EVENT_SUBSCRIBED:
+      ESP_LOGI(MQTT_TAG, "MQTT_EVENT_SUBSCRIBED, msg_id=%d", event->msg_id);
+      break;
+    case MQTT_EVENT_UNSUBSCRIBED:
+      ESP_LOGI(MQTT_TAG, "MQTT_EVENT_UNSUBSCRIBED, msg_id=%d", event->msg_id);
+      break;
+    case MQTT_EVENT_PUBLISHED:
+      ESP_LOGI(MQTT_TAG, "MQTT_EVENT_PUBLISHED, msg_id=%d", event->msg_id);
+      break;
+    case MQTT_EVENT_DATA:
+      ESP_LOGI(MQTT_TAG, "MQTT_EVENT_DATA");
+      if (strcmp(event->topic, MQTT_KEY_BOARD_ONLINE)) {
+        xEventGroupSetBits(s_mqtt_event_group, MQTT_DESKTOP_ONLINE_BIT);
+        ESP_LOGE(MQTT_TAG, "AAA MQTT_DESKTOP_ONLINE_BIT");
+      } else if (strcmp(event->topic, MQTT_KEY_DESKTOP_COLORS)) {
+        ESP_LOGE(MQTT_TAG, "AAA MQTT_DESKTOP_SENDING_BIT");
+        xEventGroupSetBits(s_mqtt_event_group, MQTT_DESKTOP_SENDING_BIT);
+      }
+      printf("TOPIC=%.*s\r\n", event->topic_len, event->topic);
+      printf("DATA=%.*s\r\n", event->data_len, event->data);
+      break;
+    case MQTT_EVENT_ERROR:
+      ESP_LOGI(MQTT_TAG, "MQTT_EVENT_ERROR");
+      xEventGroupSetBits(s_mqtt_event_group, MQTT_FAILED_BIT);
+      if (event->error_handle->error_type == MQTT_ERROR_TYPE_TCP_TRANSPORT) {
+        log_error_if_nonzero("reported from esp-tls",
+                             event->error_handle->esp_tls_last_esp_err);
+        log_error_if_nonzero("reported from tls stack",
+                             event->error_handle->esp_tls_stack_err);
+        log_error_if_nonzero("captured as transport's socket errno",
+                             event->error_handle->esp_transport_sock_errno);
+        ESP_LOGI(MQTT_TAG, "Last errno string (%s)",
+                 strerror(event->error_handle->esp_transport_sock_errno));
+      }
+      break;
+    default:
+      ESP_LOGI(MQTT_TAG, "Other event id:%d", event->event_id);
+      break;
+  }
+}
+
+static void mqtt_app_start() {
+  s_mqtt_event_group = xEventGroupCreate();
+
+  const esp_mqtt_client_config_t mqtt_cfg = {
+      .uri = "mqtt://192.168.31.11",
+  };
+  esp_mqtt_client_handle_t client = esp_mqtt_client_init(&mqtt_cfg);
+  esp_mqtt_client_register_event(client, ESP_EVENT_ANY_ID, mqtt_event_handler,
+                                 client);
+  esp_mqtt_client_start(client);
+}
+
+static bool waiting_for_mqtt_connected() {
+  EventBits_t bits = xEventGroupWaitBits(s_mqtt_event_group,
+                                         MQTT_CONNECTED_BIT | MQTT_FAILED_BIT,
+                                         pdFALSE, pdFALSE, portMAX_DELAY);
+
+  if (bits & MQTT_CONNECTED_BIT) {
+    return 1;
+  } else if (bits & MQTT_FAILED_BIT) {
+    ESP_LOGE(MQTT_TAG, "BBB Failed to connect to MQTT.");
+    return 0;
+  } else {
+    ESP_LOGE(MQTT_TAG, "UNEXPECTED EVENT");
+    return 0;
+  }
+}
+static bool waiting_for_desktop_online() {
+  EventBits_t bits = xEventGroupWaitBits(
+      s_mqtt_event_group, MQTT_DESKTOP_ONLINE_BIT | MQTT_DESKTOP_SENDING_BIT,
+      pdFALSE, pdFALSE, portMAX_DELAY);
+
+  if (bits & MQTT_DESKTOP_ONLINE_BIT) {
+    return 1;
+  } else if (bits & MQTT_DESKTOP_SENDING_BIT) {
+    return 1;
+  } else {
+    ESP_LOGE(MQTT_TAG, "UNEXPECTED EVENT");
+    return 0;
+  }
+}
+static bool waiting_for_desktop_sending_colors() {
+  EventBits_t bits =
+      xEventGroupWaitBits(s_mqtt_event_group, MQTT_DESKTOP_SENDING_BIT, pdFALSE,
+                          pdFALSE, portMAX_DELAY);
+
+  ESP_LOGE(MQTT_TAG, "MQTT_DESKTOP_SENDING_BIT");
+
+  if (bits & MQTT_DESKTOP_SENDING_BIT) {
+    return 1;
+  } else {
+    ESP_LOGE(MQTT_TAG, "UNEXPECTED EVENT");
+    return 0;
+  }
+}
\ No newline at end of file