给esp8266写一个通过mq2获取烟雾浓度数据的代码

好的，以下是一个简单的示例代码：

#include <ESP8266WiFi.h>
#include <PubSubClient.h>

#define WIFI_SSID "your_wifi_ssid"
#define WIFI_PASSWORD "your_wifi_password"
#define MQTT_SERVER "your_mqtt_broker_ip"
#define MQTT_PORT 1883
#define MQTT_TOPIC "smoke_sensor"

WiFiClient espClient;
PubSubClient mqttClient(espClient);

void setup() {
  Serial.begin(9600);
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }
  Serial.println("Connected to WiFi");

  mqttClient.setServer(MQTT_SERVER, MQTT_PORT);
  while (!mqttClient.connected()) {
    if (mqttClient.connect("esp8266-smoke-sensor")) {
      Serial.println("Connected to MQTT broker");
    } else {
      Serial.print("Failed to connect to MQTT broker, rc=");
      Serial.print(mqttClient.state());
      Serial.println(" retrying in 5 seconds");
      delay(5000);
    }
  }
}

void loop() {
  int smokeLevel = analogRead(A0); // read smoke sensor data

  Serial.print("Smoke level: ");
  Serial.println(smokeLevel);

  if (mqttClient.connected()) {
    mqttClient.publish(MQTT_TOPIC, String(smokeLevel).c_str());
  }

  delay(5000); // publish data every 5 seconds
}

这段代码使用了 `PubSubClient` 库，通过 WiFi 连接到 MQTT 服务器，并定期读取 MQ2 烟雾传感器的数据并将其发布到 `smoke_sensor` 主题。你需要修改代码中的 WiFi SSID、密码、MQTT 服务器地址、端口和主题，以适应你的环境。