esp32-wroom-32的联网光敏代码

以下是基于ESP32-WROOM-32的联网光敏代码示例（使用Arduino IDE）：

#include <WiFi.h>
#include <PubSubClient.h>

// WiFi信息
const char* ssid = "your_SSID";
const char* password = "your_PASSWORD";

// MQTT服务器信息
const char* mqtt_server = "your_MQTT_SERVER";
const int mqtt_port = 1883;
const char* mqtt_user = "your_MQTT_USER";
const char* mqtt_password = "your_MQTT_PASSWORD";
const char* mqtt_topic = "your_MQTT_TOPIC";

// 光敏电阻引脚
const int light_sensor_pin = 34;

// WiFi客户端
WiFiClient wifi_client;

// MQTT客户端
PubSubClient mqtt_client(wifi_client);

void setup_wifi() {
  delay(10);
  // 连接WiFi
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();
}

void reconnect_mqtt() {
  // Loop until we're reconnected
  while (!mqtt_client.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Attempt to connect
    if (mqtt_client.connect("ESP32Client", mqtt_user, mqtt_password)) {
      Serial.println("connected");
      // Once connected, publish an announcement...
      mqtt_client.publish(mqtt_topic, "hello world");
      // ... and resubscribe
      mqtt_client.subscribe(mqtt_topic);
    } else {
      Serial.print("failed, rc=");
      Serial.print(mqtt_client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}

void setup() {
  Serial.begin(115200);
  setup_wifi();
  mqtt_client.setServer(mqtt_server, mqtt_port);
  mqtt_client.setCallback(callback);
}

void loop() {
  if (!mqtt_client.connected()) {
    reconnect_mqtt();
  }
  mqtt_client.loop();

  // 读取光敏电阻值
  int light_sensor_value = analogRead(light_sensor_pin);

  // 发布光敏电阻值到MQTT服务器
  String message = String(light_sensor_value);
  mqtt_client.publish(mqtt_topic, message.c_str());
  delay(10000);
}

注意，此示例仅用于演示目的，应根据实际情况进行修改。请确保正确配置WiFi和MQTT服务器信息，并根据需要更改光敏电阻引脚和发布间隔时间。