Bi-directional MQTT demo for SORACOM Beam and Azure IoT Hub

AzureIoT_C2D.ino

#include <WioLTEforArduino.h>
#include <WioLTEClient.h>
#include <PubSubClient.h>    // https://github.com/knolleary/pubsubclient
#include <stdio.h>

#define APN               "soracom.io"
#define USERNAME          "sora"
#define PASSWORD          "sora"

#define MQTT_SERVER_HOST  "beam.soracom.io"
#define MQTT_SERVER_PORT  (1883)

#define ID                "WioLTE"
#define OUT_TOPIC         "devices/WioLTE/messages/events/"
#define IN_TOPIC          "devices/WioLTE/messages/devicebound/#"

#define INTERVAL          (60000)

WioLTE Wio;
WioLTEClient WioClient(&Wio);
PubSubClient MqttClient;

void callback(char* topic, byte* payload, unsigned int length) {
  SerialUSB.print("Subscribe:");
  for (int i = 0; i < length; i++) SerialUSB.print((char)payload[i]);
  SerialUSB.println("");
  if((payload[0] == '#')  && (length==7))
  {
    String hexstring=String((char *)payload);
    int number = (int) strtol( &hexstring[1], NULL, 16);
    int r = number >> 16;
    int g = number >> 8 & 0xFF;
    int b = number & 0xFF;
    SerialUSB.print("Setting LED as "); SerialUSB.println(hexstring);
    Wio.LedSetRGB(r,g,b);
 }
}

void setup() {
  delay(200);

  SerialUSB.println("");
  SerialUSB.println("--- START ---------------------------------------------------");
  
  SerialUSB.println("### I/O Initialize.");
  Wio.Init();
  
  SerialUSB.println("### Power supply ON.");
  Wio.PowerSupplyLTE(true);
  delay(5000);

  SerialUSB.println("### Turn on or reset.");
  if (!Wio.TurnOnOrReset()) {
    SerialUSB.println("### ERROR! ###");
    return;
  }

  SerialUSB.println("### Connecting to \""APN"\".");
  delay(5000);
  if (!Wio.Activate(APN, USERNAME, PASSWORD)) {
    SerialUSB.println("### ERROR! ###");
    return;
  }

  SerialUSB.println("### Connecting to MQTT server \""MQTT_SERVER_HOST"\"");
  MqttClient.setServer(MQTT_SERVER_HOST, MQTT_SERVER_PORT);
  MqttClient.setCallback(callback);
  MqttClient.setClient(WioClient);
  if (!MqttClient.connect(ID)) {
    SerialUSB.println("### ERROR! ###");
    return;
  }
  MqttClient.subscribe(IN_TOPIC);
}

void loop() {
  char data[100];
  sprintf(data, "{\"uptime\":%lu}", millis() / 1000);
  SerialUSB.print("Publish:");
  SerialUSB.print(data);
  SerialUSB.println("");
  MqttClient.publish(OUT_TOPIC, data);
  
err:
  unsigned long next = millis();
  while (millis() < next + INTERVAL)
  {
    MqttClient.loop();
  }
}