1. 效果演示 nbzch.cn:5080/mqtt。
本项目使用了arduino的PubSubClient库,它是用于 MQTT 消息传递的客户端库。
MQTT 是一种轻量级消息传递协议,非常适合小型设备。此库允许您发送和接收 MQTT 消息。它支持最新的 MQTT 3.1.1 协议,如果需要,可以配置为使用较旧的 MQTT 3.1。它支持所有Arduino以太网客户端兼容硬件,包括Intel Galileo/Edison,ESP8266/32和TI CC3000。
2. GPT所给程序
问:编写一段适用于esp32的arduino程序,实现Mqtt接收到主题为‘fish',内容为’on'时点亮12号引脚的led,内容为’off'时关闭12号引脚的led。
答:首先,你需要安装一个适用于ESP32的MQTT库,例如PubSubClient(点击下载)。然后,你可以使用以下代码实现你的需求:
#include <WiFi.h>
#include <PubSubClient.h>
const char* ssid = "Your_WiFi_SSID";
const char* password = "Your_WiFi_Password";
const char* mqttServer = "nbzch.cn";
const int mqttPort = 1883;
const char* mqttUser = "Your_MQTT_Username";
const char* mqttPassword = "Your_MQTT_Password";
const int ledPin = 12;
WiFiClient espClient;
PubSubClient client(espClient);
void setup() {
pinMode(ledPin, OUTPUT);
digitalWrite(ledPin, LOW);
Serial.begin(115200);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(1000);
Serial.println("Connecting to WiFi...");
}
Serial.println("Connected to WiFi");
client.setServer(mqttServer, mqttPort);
client.setCallback(callback);
while (!client.connected()) {
if (client.connect("ESP32Client", mqttUser, mqttPassword )) {
Serial.println("Connected to MQTT broker");
client.subscribe("fish");
} else {
Serial.print("Failed to connect to MQTT broker, rc=");
Serial.print(client.state());
Serial.println(" Retrying in 5 seconds...");
delay(5000);
}
}
}
void callback(char* topic, byte* payload, unsigned int length) {
String message;
for (unsigned int i = 0; i < length; i++) {
message += (char)payload[i];
}
Serial.print("Message received on topic '");
Serial.print(topic);
Serial.print("': ");
Serial.println(message);
if (strcmp(topic, "fish") == 0) {
if (message.equals("on")) {
digitalWrite(ledPin, HIGH);
Serial.println("LED turned ON");
} else if (message.equals("off")) {
digitalWrite(ledPin, LOW);
Serial.println("LED turned OFF");
}
}
}
void reconnect() {
while (!client.connected()) {
Serial.println("Attempting MQTT connection...");
if (client.connect("ESP32Client", mqttUser, mqttPassword )) {
Serial.println("Connected to MQTT broker");
client.subscribe("fish");
} else {
Serial.print("Failed to connect to MQTT broker, rc=");
Serial.print(client.state());
Serial.println(" Retrying in 5 seconds...");
delay(5000);
}
}
}
void loop() {
if (!client.connected()) {
reconnect();
}
client.loop();
}