Add alternate MQTT example

examples/MQTT/mqtt_basic_2/mqtt_basic_2.ino

@@ -0,0 +1,141 @@
+/*
+ *************************************************************************
+   RF24Ethernet Arduino library by TMRh20 - 2014-2020
+
+   Automated (mesh) wireless networking and TCP/IP communication stack for RF24 radio modules
+
+   RF24 -> RF24Network -> UIP(TCP/IP) -> RF24Ethernet
+                       -> RF24Mesh
+
+        Documentation: http://tmrh20.github.io/RF24Ethernet/
+
+ *************************************************************************
+ *
+ **** EXAMPLE REQUIRES: Arduino MQTT library: https://github.com/256dpi/arduino-mqtt/ ***
+ * Shown in Arduino Library Manager as 'MQTT' by Joel Gaehwiler
+ * 
+ *************************************************************************
+  Basic MQTT example
+
+ This sketch demonstrates the basic capabilities of the library.
+ It connects to an MQTT server then:
+  - publishes "hello world" to the topic "outTopic"
+  - subscribes to the topic "inTopic", printing out any messages
+    it receives. 
+  - it assumes the received payloads are strings not binary
+  - Continually publishes its nodeID to the outTopic
+
+ It will reconnect to the server if the connection is lost using a blocking
+ reconnect function.
+ 
+*/
+
+#include <SPI.h>
+#include <RF24.h>
+#include <RF24Network.h>
+#include <RF24Mesh.h>
+#include <RF24Ethernet.h>
+#include <MQTT.h>
+
+RF24 radio(7,8);
+RF24Network network(radio);
+RF24Mesh mesh(radio,network);
+RF24EthernetClass RF24Ethernet(radio,network,mesh);
+
+IPAddress ip(10,10,2,4);
+IPAddress gateway(10,10,2,2); //Specify the gateway in case different from the server
+IPAddress server(10,10,2,2);  //The ip of the MQTT server
+char clientID[] = {"arduinoClient   "};
+
+void messageReceived(String &topic, String &payload) {
+  //Serial.println("incoming: " + topic + " - " + payload);
+  Serial.println("incoming: ");
+  Serial.print(topic);
+  Serial.print(" - ");
+  Serial.println(payload);
+}
+
+EthernetClient ethClient;
+MQTTClient client;
+
+void connect() {
+  Serial.print("connecting...");
+  uint32_t clTimeout = millis();
+  while (!client.connect(clientID)) {
+    Serial.print(".");
+    if(millis() - clTimeout > 5001){
+      Serial.println();
+      return;
+    }    
+    uint32_t timer = millis(); 
+    //Instead of delay, keep the RF24 stack updating
+    while(millis() - timer < 1000){ Ethernet.update(); }
+  }
+
+  Serial.println("\nconnected!");
+  client.publish("outTopic","hello world");
+  client.subscribe("inTopic",2);
+}
+
+
+
+void setup()
+{
+  Serial.begin(115200);
+
+  Ethernet.begin(ip, gateway);
+
+  if (mesh.begin()) {
+    Serial.println(" OK");
+  } else {
+    Serial.println(" Failed");
+  }
+
+   //Convert the last octet of the IP address to an identifier used 
+   char str[4];
+   int test = ip[3];
+   itoa(ip[3],str,10);   
+   memcpy(&clientID[13],&str,strlen(str));
+   Serial.println(clientID);
+
+   client.begin(server, ethClient);
+   client.onMessage(messageReceived);
+
+}
+
+uint32_t mesh_timer = 0;
+uint32_t pub_timer = 0;
+
+void loop()
+{
+  Ethernet.update();
+
+  if(millis()-mesh_timer > 30000){ //Every 30 seconds, test mesh connectivity
+    mesh_timer = millis();
+    if( ! mesh.checkConnection() ){
+        if(!mesh.renewAddress()){
+          mesh.begin();
+        }
+     }
+    Serial.println();
+  }  
+  if (!client.connected()) {
+    connect();
+  }
+
+  client.loop();
+
+  // Every second, report to the MQTT server the Node ID of this node
+  if(client.connected() && millis() - pub_timer > 3000){
+    pub_timer = millis();
+    char str[4];
+    int test = ip[3];
+    itoa(ip[3],str,10);   
+    char str1[] = "Node      \r\n";
+    memcpy(&str1[5],&str,strlen(str));
+
+    client.publish("outTopic",str1);
+  }
+
+
+}