1.6. WiFi 与 BLE 通信

1.6.1. WiFi Station 模式

#include "esp_wifi.h"
#include "esp_event.h"
#include "nvs_flash.h"

static void wifi_event_handler(void *arg, esp_event_base_t base,
                               int32_t id, void *event_data)
{
    if (base == WIFI_EVENT && id == WIFI_EVENT_STA_START) {
        esp_wifi_connect();
    } else if (base == WIFI_EVENT &&
               id == WIFI_EVENT_STA_DISCONNECTED) {
        esp_wifi_connect();  // 自动重连
    } else if (base == IP_EVENT &&
               id == IP_EVENT_STA_GOT_IP) {
        ip_event_got_ip_t *event = event_data;
        ESP_LOGI(TAG, "获取到 IP: " IPSTR,
                 IP2STR(&event->ip_info.ip));
    }
}

void wifi_init_sta(void)
{
    nvs_flash_init();
    esp_netif_init();
    esp_event_loop_create_default();
    esp_netif_create_default_wifi_sta();

    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    esp_wifi_init(&cfg);

    esp_event_handler_instance_register(
        WIFI_EVENT, ESP_EVENT_ANY_ID,
        &wifi_event_handler, NULL, NULL);
    esp_event_handler_instance_register(
        IP_EVENT, IP_EVENT_STA_GOT_IP,
        &wifi_event_handler, NULL, NULL);

    wifi_config_t wifi_config = {
        .sta = {
            .ssid = "MyWiFi",
            .password = "password123",
            .threshold.authmode = WIFI_AUTH_WPA2_PSK,
        },
    };
    esp_wifi_set_mode(WIFI_MODE_STA);
    esp_wifi_set_config(WIFI_IF_STA, &wifi_config);
    esp_wifi_start();
}

1.6.2. WiFi AP 模式（软热点）

void wifi_init_ap(void)
{
    esp_netif_create_default_wifi_ap();

    wifi_config_t wifi_config = {
        .ap = {
            .ssid = "ESP32_AP",
            .ssid_len = strlen("ESP32_AP"),
            .password = "12345678",
            .max_connection = 4,
            .authmode = WIFI_AUTH_WPA_WPA2_PSK,
        },
    };

    esp_wifi_set_mode(WIFI_MODE_AP);
    esp_wifi_set_config(WIFI_IF_AP, &wifi_config);
    esp_wifi_start();

    ESP_LOGI(TAG, "AP 启动: ESP32_AP");
}

1.6.3. HTTP 客户端

#include "esp_http_client.h"

void http_get_example(void)
{
    esp_http_client_config_t config = {
        .url = "http://api.example.com/data",
        .timeout_ms = 5000,
    };

    esp_http_client_handle_t client = esp_http_client_init(&config);
    esp_err_t err = esp_http_client_perform(client);

    if (err == ESP_OK) {
        int status = esp_http_client_get_status_code(client);
        int len = esp_http_client_get_content_length(client);
        ESP_LOGI(TAG, "HTTP 状态: %d, 长度: %d", status, len);
    }

    esp_http_client_cleanup(client);
}

1.6.4. MQTT 客户端

#include "mqtt_client.h"

static void mqtt_event_handler(void *handler_args,
    esp_event_base_t base, int32_t event_id, void *event_data)
{
    esp_mqtt_event_handle_t event = event_data;
    switch (event->event_id) {
        case MQTT_EVENT_CONNECTED:
            ESP_LOGI(TAG, "MQTT 已连接");
            esp_mqtt_client_subscribe(event->client,
                                      "/topic/test", 1);
            break;
        case MQTT_EVENT_DATA:
            printf("收到: %.*s => %.*s\n",
                  event->topic_len, event->topic,
                  event->data_len, event->data);
            break;
        default:
            break;
    }
}

void mqtt_app_start(void)
{
    esp_mqtt_client_config_t mqtt_cfg = {
        .broker.address.uri = "mqtt://broker.emqx.io:1883",
        .broker.address.port = 1883,
    };

    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, NULL);
    esp_mqtt_client_start(client);

    // 发布消息
    esp_mqtt_client_publish(client, "/topic/test",
                           "Hello ESP32", 0, 1, 0);
}

1.6.5. BLE 蓝牙

// BLE Server 示例（基于 NimBLE 或 Bluedroid）

#include "esp_bt.h"
#include "esp_bt_main.h"
#include "esp_gap_ble_api.h"
#include "esp_gatts_api.h"

#define GATTS_TAG            "GATTS_DEMO"
#define PROFILE_NUM           1
#define DEVICE_NAME           "ESP32_BLE"

void ble_init(void)
{
    ESP_ERROR_CHECK(esp_bt_controller_mem_release(
        ESP_BT_MODE_CLASSIC_BT));

    esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
    esp_bt_controller_init(&bt_cfg);
    esp_bt_controller_enable(ESP_BT_MODE_BTDM);

    esp_bluedroid_init();
    esp_bluedroid_enable();
}

小技巧

ESP-IDF 支持两种 BLE 协议栈：

Bluedroid：功能完整，内存占用大（~1.5 MB），支持 Classic BT
NimBLE：轻量实现，内存占用小（~400 KB），仅 BLE

在 menuconfig → Component config → Bluetooth 中切换。

1.6.5.1. BLE 扫描（MicroPython）

import bluetooth
import time

ble = bluetooth.BLE()
ble.active(True)

def bt_irq(event, data):
    if event == 5:  # _IRQ_SCAN_RESULT
        addr_type, addr, adv_type, rssi, adv_data = data
        name = ""
        # 解析广播数据中的名字
        print(f"发现设备: {addr.hex()}, RSSI: {rssi}")

ble.irq(bt_irq)
ble.gap_scan(30000, 30000, True)