Adafruit_MQTT_Library/examples/mqtt_fona/mqtt_fona.ino

#include <Adafruit_SleepyDog.h>
#include <SoftwareSerial.h>
#include "Adafruit_FONA.h"
#include "Adafruit_MQTT.h"
#include "Adafruit_MQTT_FONA.h"

/*************************** FONA Pins ***********************************/

#define FONA_RX 2
#define FONA_TX 3
#define FONA_RST 4
SoftwareSerial fonaSS = SoftwareSerial(FONA_TX, FONA_RX);

Adafruit_FONA fona = Adafruit_FONA(FONA_RST);

/************************* WiFi Access Point *********************************/

  // Optionally configure a GPRS APN, username, and password.
  // You might need to do this to access your network's GPRS/data
  // network.  Contact your provider for the exact APN, username,
  // and password values.  Username and password are optional and
  // can be removed, but APN is required.
#define FONA_APN       ""
#define FONA_USERNAME  ""
#define FONA_PASSWORD  ""

/************************* Adafruit.io Setup *********************************/

#define AIO_SERVER      "io.adafruit.com"
#define AIO_SERVERPORT  1883
#define AIO_USERNAME    "...your AIO username (see https://accounts.adafruit.com)..."
#define AIO_KEY         "...your AIO key...";

/************ Global State (you don't need to change this!) ******************/

// Store the MQTT server, client ID, username, and password in flash memory.
// This is required for using the Adafruit MQTT library.
const char MQTT_SERVER[] PROGMEM    = AIO_SERVER;
const char MQTT_CLIENTID[] PROGMEM  = AIO_KEY;
const char MQTT_USERNAME[] PROGMEM  = AIO_USERNAME;
const char MQTT_PASSWORD[] PROGMEM  = AIO_KEY;

// Setup the FONA MQTT class by passing in the FONA class and MQTT server and login details.
Adafruit_MQTT_FONA mqtt(&fona, MQTT_SERVER, AIO_SERVERPORT, MQTT_CLIENTID, MQTT_USERNAME, MQTT_PASSWORD);

// You don't need to change anything below this line!
#define halt(s) { Serial.println(F( s )); while(1);  }

// FONAconnect is a helper function that sets up the FONA and connects to
// the GPRS network. See the fonahelper.cpp tab above for the source!
boolean FONAconnect(const __FlashStringHelper *apn, const __FlashStringHelper *username, const __FlashStringHelper *password);

/****************************** Feeds ***************************************/

// Setup a feed called 'photocell' for publishing.  
// Notice MQTT paths for AIO follow the form: <username>/feeds/<feedname>
const char PHOTOCELL_FEED[] PROGMEM = AIO_USERNAME "/feeds/photocell";
Adafruit_MQTT_Publish photocell = Adafruit_MQTT_Publish(&mqtt, PHOTOCELL_FEED);

// Setup a feed called 'onoff' for subscribing to changes.  
const char ONOFF_FEED[] PROGMEM = AIO_USERNAME "/feeds/onoff";
Adafruit_MQTT_Subscribe onoffbutton = Adafruit_MQTT_Subscribe(&mqtt, ONOFF_FEED);

/*************************** Sketch Code ************************************/

// How many transmission failures in a row we're willing to be ok with before reset
uint8_t txfailures = 0;
#define MAXTXFAILURES 3

void setup() {
  while (!Serial);

  Serial.begin(115200);

  Serial.println(F("Adafruit FONA MQTT demo"));


  mqtt.subscribe(&onoffbutton);

  // Initialise the FONA module
  while (! FONAconnect(F(FONA_APN), F(FONA_USERNAME), F(FONA_PASSWORD))) {
    halt("Retrying FONA");
  }

  Serial.println(F("Connected to Cellular!"));

  Watchdog.reset();
  delay(3000);  // wait a few seconds to stabilize connection
  Watchdog.reset();
}

uint32_t x=0;

void loop() {
  // Make sure to reset watchdog every loop iteration!
  Watchdog.reset();

  // check if we're still connected
  if (!fona.TCPconnected() || (txfailures >= MAXTXFAILURES)) {
    //////////////////////////////
    Serial.println(F("Connecting to MQTT..."));
    int8_t ret, retries = 5;
    while (retries && (ret = mqtt.connect()) != 0) {
       switch (ret) {
          case 1: Serial.println(F("Wrong protocol")); break;
          case 2: Serial.println(F("ID rejected")); break;
          case 3: Serial.println(F("Server unavail")); break;
          case 4: Serial.println(F("Bad user/pass")); break;
          case 5: Serial.println(F("Not authed")); break;
          case 6: Serial.println(F("Failed to subscribe")); break;
          default: {
            Serial.println(F("Connection failed")); 
            break;
          }
       }
       Serial.println(F("Retrying MQTT connection"));
       retries--;
       if (retries == 0) halt("Resetting system");
       delay(5000); 
    }
    Serial.println(F("MQTT Connected!"));
    txfailures = 0; 
  }

 
  // Try to ping the MQTT server
  /*
  if (! mqtt.ping(3) ) {
    // MQTT pings failed, lets reconnect
    Serial.println("Ping fail!");
  }
  */
  

  // this is our 'wait for incoming subscription packets' busy subloop
  Adafruit_MQTT_Subscribe *subscription;
  while (subscription = mqtt.readSubscription(5000)) {
    if (subscription == &onoffbutton) {
      Serial.print(F("Got: ")); 
      Serial.println((char *)onoffbutton.lastread);
    }
  }
  
  // Now we can publish stuff!
  Serial.print(F("\nSending photocell val ")); 
  Serial.print(x);
  Serial.print("...");
  if (! photocell.publish(x++)) {
    Serial.println(F("Failed"));
    txfailures++;
  } else {
    Serial.println(F("OK!"));
    txfailures = 0;
  }
}