Example adjustments, new example

- Add non-blocking connect MQTT example
- Remove unused variable `test`
- Put timer calculations outside loops
- Add new example file to docs

RF24Ethernet.h

@@ -272,6 +272,12 @@ typedef RF24EthernetClass RF52EthernetClass;
  * This is the example taken from the PubSub library (https://github.com/knolleary/pubsubclient) & slightly modified to include RF24Ethernet/RF24Mesh.
  */
 
+/**
+ * @example mqtt_basic_no_blk.ino
+ *
+ * This is similar to the mqtt_basic example, but uses a non-blocking connect function.
+ */
+
 /**
  * @example mqtt_basic_2.ino
  *

examples/MQTT/mqtt_basic/mqtt_basic.ino

@@ -59,17 +59,17 @@ MQTTClient client;
 
 void connect() {
   Serial.print("connecting...");
-  uint32_t clTimeout = millis();
+  uint32_t clTimeout = millis() + 5001;
   while (!client.connect(clientID)) {
     Serial.print(".");
-    if (millis() - clTimeout > 5001) {
+    if (millis() > clTimeout) {
       Serial.println();
       mesh.renewAddress();
       return;
     }
-    uint32_t timer = millis();
+    uint32_t timer = millis() + 1000;
     //Instead of delay, keep the RF24 stack updating
-    while (millis() - timer < 1000) {
+    while (millis() < timer) {
       Ethernet.update();
     }
   }
@@ -92,7 +92,6 @@ void setup() {
 
   //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);
@@ -126,7 +125,6 @@ void loop() {
   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));

examples/MQTT/mqtt_basic_2/mqtt_basic_2.ino

@@ -60,17 +60,17 @@ MQTTClient client;
 
 void connect() {
   Serial.print("connecting...");
-  uint32_t clTimeout = millis();
+  uint32_t clTimeout = millis() + 5001;
   while (!client.connect(clientID)) {
     Serial.print(".");
-    if (millis() - clTimeout > 5001) {
+    if (millis() > clTimeout) {
       mesh.renewAddress();
       Serial.println();
       return;
     }
-    uint32_t timer = millis();
+    uint32_t timer = millis() + 1000;
     //Instead of delay, keep the RF24 stack updating
-    while (millis() - timer < 1000) {
+    while (millis() < timer) {
       Ethernet.update();
     }
   }
@@ -93,7 +93,6 @@ void setup() {
 
   //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);
@@ -127,7 +126,6 @@ void loop() {
   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));

examples/MQTT/mqtt_basic_no_blk/mqtt_basic_no_blk.ino

@@ -0,0 +1,122 @@
+/*
+ *************************************************************************
+   RF24Ethernet Arduino library by TMRh20 - 2014-2021
+
+   Automated (mesh) wireless networking and TCP/IP communication stack for RF24 radio modules
+
+   RF24 -> RF24Network -> UIP(TCP/IP) -> RF24Ethernet
+                       -> RF24Mesh
+
+        Documentation: http://nRF24.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 non-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(MQTTClient* client, char topic[], char payload[], int length) {
+  Serial.println("incoming: ");
+  Serial.print(topic);
+  Serial.print(" - ");
+  Serial.println(payload);
+}
+
+EthernetClient ethClient;
+MQTTClient client;
+
+void connect() {
+  Serial.println("connecting...");
+  if (!client.connect(clientID)) {
+    mesh.renewAddress();
+    return;
+  }
+  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];
+  itoa(ip[3], str, 10);
+  memcpy(&clientID[13], &str, strlen(str));
+  Serial.println(clientID);
+
+  client.begin(server, ethClient);
+  client.onMessageAdvanced(messageReceived);
+}
+
+
+uint32_t pub_timer = 0;
+
+void loop() {
+
+  Ethernet.update();
+
+  if (!client.connected()) {
+    if (!mesh.checkConnection()) {
+      if (mesh.renewAddress() == MESH_DEFAULT_ADDRESS) {
+        mesh.begin();
+      }
+    }
+    connect();
+    Serial.println();
+  }
+
+  client.loop();
+
+  // Every so often, report to the MQTT server the Node ID of this node
+  if (client.connected() && millis() - pub_timer > 3000) {
+    pub_timer = millis();
+    char str[4];
+    itoa(ip[3], str, 10);
+    char str1[] = "Node      \r\n";
+    memcpy(&str1[5], &str, strlen(str));
+
+    client.publish("outTopic", str1);
+  }
+}