物联网编程简单程序代码

以下是一个简单的物联网编程程序代码示例：

#include

#include

const char* ssid = "your_SSID";

const char* password = "your_PASSWORD";

const char* mqtt_server = "mqtt_broker_IP";

WiFiClient espClient;

PubSubClient client(espClient);

void setup() {

Serial.begin(115200);

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());

client.setServer(mqtt_server, 1883);

}

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() {

while (!client.connected()) {

Serial.print("Attempting MQTT connection...");

if (client.connect("ESP8266Client")) {

Serial.println("connected");

client.subscribe("testTopic");

} else {

Serial.print("failed, rc=");

Serial.print(client.state());

Serial.println(" try again in 5 seconds");

delay(5000);

}

}

}

void loop() {

if (!client.connected()) {

reconnect();

}

client.loop();

}

这个代码使用了ESP8266 WiFi模块和PubSubClient库来连接WiFi和MQTT服务器。它先连接WiFi，然后尝试连接MQTT服务器并订阅"testTopic"主题。当从服务器接收到消息时，它会调用callback函数来处理消息。在主循环中，程序会检查MQTT连接的状态并通过client.loop()来处理来自服务器的消息。