闪烁在arduino中使用MQTT引导

Question

我必须实现一个原型场景，使用MQTT协议在arduino中闪烁LED。我已经尝试了几个MQTT库，但其中没有一个完美无缺。与MQTT代理的连接工作成功，但是当我发布带有在arduino中设置的主题的消息时，不会使LED闪烁。 Arduno要发布的消息，当它连接成功，但这种公布部分还没有工作

这是我的代码

#include <SPI.h> 
#include <Ethernet.h> 
#include <PubSubClient.h> 

// Set the MAC address 
byte mac[] = { 0xDE, 0xED, 0xBA, 0xFE, 0xFE, 0xED }; 
IPAddress ip(192, 168, 1, 100); 
IPAddress server(192, 168, 1, 20); 

// Set what PINs our Led's are connected to 
int redPin = 13;     
//int greenPin = 6; 
//int bluePin = 7; 

// Set a generic code that will trigger our Blue Led 
// think of this as a set of codes for automation you might write 
byte triggerRed[13] = "12345"; 

// handles messages that are returned from the broker on our subscribed channel 
void callback(char* topic, byte* payload, unsigned int length) { 

    Serial.print("New message from broker on topic:"); 
    Serial.println(topic); 

    Serial.print("Payload:"); 
    Serial.write(payload, length); 



    // Check and see if our payload matches our simple trigger test 
    if ((length == 5) & (memcmp(payload, triggerRed, 5) == 0)) 
    { 
    //blink(redPin); 

    } 

} 
EthernetClient ethClient; 
PubSubClient client(ethClient); 
// Fire up our PubSub client 
//PubSubClient client(server, 1883, callback); 

void setup() 
{ 

    // Open serial communications 
    Serial.begin(9600); 

    client.setServer(server, 1883); 
    client.setCallback(callback); 

    // Setup our Leds 
    pinMode(redPin, OUTPUT); 
// pinMode(greenPin, OUTPUT); 
// pinMode(bluePin, OUTPUT); 

    // attempt a DHCP connection 
    Serial.println("Attempting to get an IP address using DHCP:"); 
    if (!Ethernet.begin(mac)) 
    { 
    // if DHCP fails, start with a hard-coded address: 
    Serial.println("failed to get an IP address using DHCP, trying manually"); 
    Ethernet.begin(mac, ip); 
    } 

    Serial.print("My address:"); 
    Serial.println(Ethernet.localIP()); 

    // Connect to Broker, give it arduino as the name 
    if (client.connect("arduino")) { 

    // Good, we connected turn on the red led 
    digitalWrite(redPin, HIGH); 

    // Publish a message to the status topic 
    client.publish("status","Arduino is now online"); 

    // Listen for messages on the control topic 
    client.subscribe("ultra"); 
    } 

} 

void loop() 
{ 
    client.loop(); 
} 

// Anything with flashing lights. 
void blink(int targetLed) 
{ 
    digitalWrite(redPin, HIGH); 

} 

我怎样才能解决这个问题？

Answer 1

将连接例程放入循环中，并首先尝试使用test.mosquitto.org。 这里是代码为我（以太网屏蔽硬件）的工作原理：

定义：

#define CLIENT_NAME "myclientname" 
#define TOPIC "mytopic" 
byte mac[] = { 0xDE, 0xED, 0xBA, 0xFE, 0xFE, 0xED }; 
IPAddress ip(192, 168, 1, 105); 
IPAddress server(85, 119, 83, 194);// test.mosquitto.org 
#define MQTT_PORT 1883 
IPAddress myDns(8, 8, 8, 8); 
EthernetClient ethClient; 
PubSubClient client(ethClient); 

设置：

client.setServer(server, MQTT_PORT); 
client.setCallback(callback); 
Ethernet.begin(mac); 

循环：

if (!client.connected()) { 
      reconnect(); 
     } 
client.loop(); 

重新例行

void reconnect() { 
    if (millis() - reconnectionTimer >reconnection_period){// Loop until we're reconnected 
     reconnectionTimer = millis(); 
     if (!client.connected()) { 
      // Attempt to connect 
      if (client.connect(CLIENT_NAME)) { 
       client.subscribe(TOPIC); 
      } 
      else { 
       Serial.print(client.state()); 
       Serial3.print(client.state()); 
      } 
     } 
    } 
} 

---

更新眨眼：

void blink(){ 
    digitalWrite(led, LOW); 
    delay(500); 
    digitalWrite(led, HIGH); 
}