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ESP8266+MQTT怎么实现LED灯的远程控制

发表于：2025-01-31 作者：千家信息网编辑

千家信息网最后更新 2025年01月31日，这篇文章主要讲解了"ESP8266+MQTT怎么实现LED灯的远程控制"，文中的讲解内容简单清晰，易于学习与理解，下面请大家跟着小编的思路慢慢深入，一起来研究和学习"ESP8266+MQTT怎么实现L

千家信息网最后更新 2025年01月31日ESP8266+MQTT怎么实现LED灯的远程控制

这篇文章主要讲解了"ESP8266+MQTT怎么实现LED灯的远程控制"，文中的讲解内容简单清晰，易于学习与理解，下面请大家跟着小编的思路慢慢深入，一起来研究和学习"ESP8266+MQTT怎么实现LED灯的远程控制"吧！

MQTT 是轻量级的、灵活的物联网消息交换和数据传递协议，致力于为 IoT 开发人员实现灵活性与硬件/网络资源的平衡。

NodeMCU 是一个开源的物联网平台。它使用 Lua 语言编程。该平台基于eLua开源项目，底层使用ESP8266 sdk 0.9.5版本。

在此项目中我们将实现 NodeMCU(ESP8266) 与 EMQ X Cloud 运营和维护的免费公共 MQTT 服务器远程控制 LED 灯，并使用 Arduino IDE 来对 NodeMCU ESP8266 进行编程。 EMQ X Cloud 是由 EMQ 推出的安全的 MQTT 物联网云服务平台，它提供一站式运维代管、独有隔离环境的 MQTT 5.0 接入服务。

所需组件

NodeMCU
Arduino IDE
LED * 1，330 Ω 电阻
MQTT X: 优雅的跨平台 MQTT 5.0 客户端工具
免费的公共 MQTT 服务器

Broker: broker.emqx.io
TCP Port: 1883
Websocket Port: 8083

NodeMCU ESP8266 和 LED 连接图

代码编写

首先我们将导入 ESP8266WiFi 和 PubSubClient 库，ESP8266WiFi 库能够将 ESP8266 连接到 WiFi 网络，PubSubClient 库，使我们能够连接到 MQTT 代理并发布/订阅主题消息。
```
#include #include 
```
我们将使用 NodeMCU ESP8266 的 D1 引脚来连接到 LED，实际上该引脚内部连接到 ESP8266 模块的 GPIO5。
```
// GPIO 5 D1#define LED 5
```

设置 WIFI 名称和密码，以及 MQTT Broker 连接地址和端口

// WiFiconst char *ssid = "mousse"; // Enter your WiFi nameconst char *password = "qweqweqwe";  // Enter WiFi password// MQTT Brokerconst char *mqtt_broker = "broker.emqx.io";const char *topic = "esp8266/led";const char *mqtt_username = "emqx";const char *mqtt_password = "public";const int mqtt_port = 1883;

我们打开了一个串行连接，以便于输出程序的结果并且连接到WiFi网络

// Set software serial baud to 115200;Serial.begin(115200);// connecting to a WiFi networkWiFi.begin(ssid, password);while (WiFi.status() != WL_CONNECTED) {    delay(500);    Serial.println("Connecting to WiFi..");}

我们将设置 MQTT Broker，同时将连接信息打印到串口监视器上

 //connecting to a mqtt brokerclient.setServer(mqtt_broker, mqtt_port);client.setCallback(callback);while (!client.connected()) {    String client_id = "esp8266-client-";    client_id += String(WiFi.macAddress());    Serial.println("Connecting to public emqx mqtt broker.....");    if (client.connect(client_id, mqtt_username, mqtt_password)) {        Serial.println("Public emqx mqtt broker connected");    } else {        Serial.print("failed with state ");        Serial.print(client.state());        delay(2000);    }}

MQTT Broker 连接成功后，ESP8266 将向 MQTT Broker 发布和订阅消息

// publish and subscribeclient.publish(topic, "hello emqx");client.subscribe(topic);

编写回调函数，从串行监视器读取下发指令并且控制 LED 的开和关

void callback(char *topic, byte *payload, unsigned int length) {    Serial.print("Message arrived in topic: ");    Serial.println(topic);    Serial.print("Message:");    String message;    for (int i = 0; i < length; i++) {        message = message + (char) payload[i];  // convert *byte to string    }    Serial.print(message);    if (message == "on") { digitalWrite(LED, LOW); }   // LED on    if (message == "off") { digitalWrite(LED, HIGH); } // LED off    Serial.println();    Serial.println("-----------------------");}

完整代码

#include #include // GPIO 5 D1#define LED 5// WiFiconst char *ssid = "mousse"; // Enter your WiFi nameconst char *password = "qweqweqwe";  // Enter WiFi password// MQTT Brokerconst char *mqtt_broker = "broker.emqx.io";const char *topic = "esp8266/led";const char *mqtt_username = "emqx";const char *mqtt_password = "public";const int mqtt_port = 1883;WiFiClient espClient;PubSubClient client(espClient);void setup() {    // Set software serial baud to 115200;    Serial.begin(115200);    // connecting to a WiFi network    WiFi.begin(ssid, password);    while (WiFi.status() != WL_CONNECTED) {        delay(500);        Serial.println("Connecting to WiFi..");    }    Serial.println("Connected to the WiFi network");    //connecting to a mqtt broker    client.setServer(mqtt_broker, mqtt_port);    client.setCallback(callback);    while (!client.connected()) {        String client_id = "esp8266-client-";        client_id += String(WiFi.macAddress());        Serial.println("Connecting to public emqx mqtt broker.....");        if (client.connect(client_id, mqtt_username, mqtt_password)) {            Serial.println("Public emqx mqtt broker connected");        } else {            Serial.print("failed with state ");            Serial.print(client.state());            delay(2000);        }    }    // publish and subscribe    client.publish(topic, "hello emqx");    client.subscribe(topic);}void callback(char *topic, byte *payload, unsigned int length) {    Serial.print("Message arrived in topic: ");    Serial.println(topic);    Serial.print("Message:");    String message;    for (int i = 0; i < length; i++) {        message = message + (char) payload[i];  // convert *byte to string    }    Serial.print(message);    if (message == "on") { digitalWrite(LED, LOW); }   // LED on    if (message == "off") { digitalWrite(LED, HIGH); } // LED off    Serial.println();    Serial.println("-----------------------");}void loop() {    client.loop();}