ESP32在阿里云平臺使用MQTT協議控制RGB燈

本章內容是在ESP-IDF的\examples\protocols\mqtt\tcp工程上進行修改，實現ESP32在阿里云平臺使用MQTT協議控制RGB燈。

在實驗前需要在阿里云平臺創建產品并添加設備，獲取三元組信息。最后在產品屬性里添加HSV調色（我們用這個替代RGB數據傳輸）。

一、主程序步驟

1.1 對NVS以及網絡進行初始化，連接WIFI:

ESP_ERROR_CHECK(nvs_flash_init()); ESP_ERROR_CHECK(esp_netif_init()); ESP_ERROR_CHECK(esp_event_loop_create_default()); ESP_ERROR_CHECK(example_connect());

注：在連接WIFI前需要用idf.py menuconfig來配置要連接的路由器信息。

1.2 啟動mqtt:

實現一個啟動函數：mqtt_app_start()

1.2.1 配置信息

根據從阿里云獲取的三元組信息，來配置mqtt_client信息。

esp_mqtt_client_config_t mqtt_cfg = {//.uri = CONFIG_BROKER_URL,.host = "a1Swb0u95bV.iot-as-mqtt.cn-shanghai.aliyuncs.com",.port = 1883,.client_id = "XP001|securemode=3,signmethod=hmacsha1|",.username = "XP001&a1Swb0u95bV",.password = "df8e0bbf849758e0cedb9d5c5854c345598c52d7",};

1.2.2創建client

根據上一步配置信息來創建一個client。

esp_mqtt_client_handle_t client = esp_mqtt_client_init(&mqtt_cfg);

1.2.3: 注冊mqtt句柄

esp_mqtt_client_register_event(client, ESP_EVENT_ANY_ID, mqtt_event_handler, client);

mqtt相關事件處理都在此函數中，后詳述。

1.2.4: 根據句柄啟動mqtt

esp_mqtt_client_start(client);

1.3mqtt_event_handler處理函數

此函數實際操作的是mqtt_event_handler_cb()回調函數。由于控制RGB事件比較小，只用到了連接、訂閱兩個控制事件。

static esp_err_t mqtt_event_handler_cb(esp_mqtt_event_handle_t event) {esp_mqtt_client_handle_t client = event->client;int msg_id;switch (event->event_id) {case MQTT_EVENT_CONNECTED: //連接msg_id = esp_mqtt_client_subscribe(client, "/sys/a1Swb0u95bV/XP001/thing/service/property/set", 0);//訂閱主題ESP_LOGI(TAG, "sent subscribe successful, msg_id=%d", msg_id);break;case MQTT_EVENT_DISCONNECTED://...break;case MQTT_EVENT_SUBSCRIBED://...break;case MQTT_EVENT_UNSUBSCRIBED://...break;case MQTT_EVENT_PUBLISHED://...break;case MQTT_EVENT_DATA: //從服務器發送過來的數據ESP_LOGI(TAG, "MQTT_EVENT_DATA");printf("TOPIC=%.*s\r\n", event->topic_len, event->topic);printf("DATA=%.*s\r\n", event->data_len, event->data);cJSON *root = cJSON_Parse(event->data);if (!root) {printf("JSON format error:%s \r\n", cJSON_GetErrorPtr());} else {cJSON *item = cJSON_GetObjectItem(root, "params"); //解析JSON數據cJSON *rgb_item = cJSON_GetObjectItem(item, "HSVColor");int32_t red = cJSON_GetObjectItem(rgb_item, "r_val")->valueint;int32_t green = cJSON_GetObjectItem(rgb_item, "g_val")->valueint;int32_t blue = cJSON_GetObjectItem(rgb_item, "b_val")->valueint; cJSON_Delete(root);if (red != g_red || green != g_green || blue != g_blue) { //根據接收的數據設置RGBg_red = red;g_green = green;g_blue = blue;ESP_LOGI(TAG, "Light control: red = %d, green = %d, blue = %d", g_red, g_green, g_blue);ESP_ERROR_CHECK(g_leds->set_rgb(g_leds, g_red, g_green, g_blue));}} break;case MQTT_EVENT_ERROR://..break;default://...break;}return ESP_OK; }

在JSON解析需要知道數據格式，在RGB控制中，數據格式如下所示：

{"method" : "thing.service.property.set","id" : "1664271450","params" : {"HSVColor": {"r_val": 255, "g_val": 100,"b_val": 100}},"version" : "1.0.0" }

2 調試

首先打開設備的在線調試，如下圖所示：

然后發送RGB數據，數據格式見下圖：

實驗結果如下圖：

3 源程序

為了方便學習與記憶，附上主程序。

static const char *TAG = "MQTT_EXAMPLE"; static led_rgb_t *g_leds = NULL; static uint8_t g_red; static uint8_t g_green; static uint8_t g_blue; static TaskHandle_t g_breath_light_task_handle = NULL;//static const char *public_aliyun[] = {};static esp_err_t mqtt_event_handler_cb(esp_mqtt_event_handle_t event) {esp_mqtt_client_handle_t client = event->client;int msg_id;// your_context_t *context = event->context;switch (event->event_id) {case MQTT_EVENT_CONNECTED:ESP_LOGI(TAG, "MQTT_EVENT_CONNECTED");msg_id = esp_mqtt_client_subscribe(client, "/sys/a1Swb0u95bV/XP001/thing/service/property/set", 0);ESP_LOGI(TAG, "sent subscribe successful, msg_id=%d", msg_id);break;case MQTT_EVENT_DISCONNECTED:ESP_LOGI(TAG, "MQTT_EVENT_DISCONNECTED");break;case MQTT_EVENT_SUBSCRIBED:ESP_LOGI(TAG, "MQTT_EVENT_SUBSCRIBED, msg_id=%d", event->msg_id);msg_id = esp_mqtt_client_publish(client, "/topic/qos0", "data", 0, 0, 0);ESP_LOGI(TAG, "sent publish successful, msg_id=%d", msg_id);break;case MQTT_EVENT_UNSUBSCRIBED:ESP_LOGI(TAG, "MQTT_EVENT_UNSUBSCRIBED, msg_id=%d", event->msg_id);break;case MQTT_EVENT_PUBLISHED:ESP_LOGI(TAG, "MQTT_EVENT_PUBLISHED, msg_id=%d", event->msg_id);break;case MQTT_EVENT_DATA:ESP_LOGI(TAG, "MQTT_EVENT_DATA");printf("TOPIC=%.*s\r\n", event->topic_len, event->topic);printf("DATA=%.*s\r\n", event->data_len, event->data);cJSON *root = cJSON_Parse(event->data);if (!root) {printf("JSON format error:%s \r\n", cJSON_GetErrorPtr());} else {cJSON *item = cJSON_GetObjectItem(root, "params");//int32_t val = cJSON_GetObjectItem(item, "PowerSwitch")->valueint;cJSON *rgb_item = cJSON_GetObjectItem(item, "HSVColor");int32_t red = cJSON_GetObjectItem(rgb_item, "r_val")->valueint;int32_t green = cJSON_GetObjectItem(rgb_item, "g_val")->valueint;int32_t blue = cJSON_GetObjectItem(rgb_item, "b_val")->valueint;cJSON_Delete(root);if (red != g_red || green != g_green || blue != g_blue) {g_red = red;g_green = green;g_blue = blue;ESP_LOGI(TAG, "Light control: red = %d, green = %d, blue = %d", g_red, g_green, g_blue);ESP_ERROR_CHECK(g_leds->set_rgb(g_leds, g_red, g_green, g_blue));}} break;case MQTT_EVENT_ERROR:ESP_LOGI(TAG, "MQTT_EVENT_ERROR");break;default:ESP_LOGI(TAG, "Other event id:%d", event->event_id);break;}return ESP_OK; }static void mqtt_event_handler(void *handler_args, esp_event_base_t base, int32_t event_id, void *event_data) {ESP_LOGD(TAG, "Event dispatched from event loop base=%s, event_id=%d", base, event_id);mqtt_event_handler_cb(event_data); }static void mqtt_app_start(void) {esp_mqtt_client_config_t mqtt_cfg = {//.uri = CONFIG_BROKER_URL,.host = "a1Swb0u95bV.iot-as-mqtt.cn-shanghai.aliyuncs.com",.port = 1883,.client_id = "XP001|securemode=3,signmethod=hmacsha1|",.username = "XP001&a1Swb0u95bV",.password = "df8e0bbf849758e0cedb9d5c5854c345598c52d7",}; #if CONFIG_BROKER_URL_FROM_STDINchar line[128];if (strcmp(mqtt_cfg.uri, "FROM_STDIN") == 0) {int count = 0;printf("Please enter url of mqtt broker\n");while (count < 128) {int c = fgetc(stdin);if (c == '\n') {line[count] = '\0';break;} else if (c > 0 && c < 127) {line[count] = c;++count;}vTaskDelay(10 / portTICK_PERIOD_MS);}mqtt_cfg.uri = line;printf("Broker url: %s\n", line);} else {ESP_LOGE(TAG, "Configuration mismatch: wrong broker url");abort();} #endif /* CONFIG_BROKER_URL_FROM_STDIN */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 void breath_light_task(void *arg) {uint8_t value = 0;uint8_t dir = 0;while (1) {ESP_ERROR_CHECK(g_leds->set_hsv(g_leds, 60, 50, 100));vTaskDelay(pdMS_TO_TICKS(20));} }void app_main(void) {ESP_LOGI(TAG, "[APP] Startup..");ESP_LOGI(TAG, "[APP] Free memory: %d bytes", esp_get_free_heap_size());ESP_LOGI(TAG, "[APP] IDF version: %s", esp_get_idf_version());esp_log_level_set("*", ESP_LOG_INFO);esp_log_level_set("MQTT_CLIENT", ESP_LOG_VERBOSE);esp_log_level_set("MQTT_EXAMPLE", ESP_LOG_VERBOSE);esp_log_level_set("TRANSPORT_TCP", ESP_LOG_VERBOSE);esp_log_level_set("TRANSPORT_SSL", ESP_LOG_VERBOSE);esp_log_level_set("TRANSPORT", ESP_LOG_VERBOSE);esp_log_level_set("OUTBOX", ESP_LOG_VERBOSE);ESP_ERROR_CHECK(nvs_flash_init());ESP_ERROR_CHECK(esp_netif_init());ESP_ERROR_CHECK(esp_event_loop_create_default());led_rgb_config_t rgb_config = LED_RGB_DEFAULT_CONFIG(BOARD_GPIO_LED_R, BOARD_GPIO_LED_G, BOARD_GPIO_LED_B);g_leds = led_rgb_create(&rgb_config);if (!g_leds) {ESP_LOGE(TAG, "install LED driver failed");}//xTaskCreatePinnedToCore(breath_light_task, "breath_light_task", 1024 * 3, NULL, 5, &g_breath_light_task_handle, 1);ESP_ERROR_CHECK(example_connect());// vTaskDelete(g_breath_light_task_handle);ESP_ERROR_CHECK(g_leds->set_hsv(g_leds, 60, 10, 50));mqtt_app_start(); }

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