Build a Weather Station using XinaBox xChips and Azure IoT

#include <WiFi.h>
#include <xCore.h>
#include <xSW01.h>

#include "AzureIotHub.h"
#include "Esp32MQTTClient.h"



//keep alive interval

#define MQTT_KEEPALIVE_INTERVAL_S 120

#define DEVICE_ID "CW02"

#define MESSAGE_MAX_LEN 256

xSW01 SW01;

// Please input the SSID and password of WiFi

const char* ssid     = "";

const char* password = "";



//Set msg_Interval to set transmit frequency
unsigned long msg_Interval = 10000;

unsigned long msg_Timer = 0;



unsigned long stream_Interval = 20000;

unsigned long stream_Timer = 0;

/*String containing Hostname, Device Id & Device Key in the format:                         */

/*  "HostName=<host_name>;DeviceId=<device_id>;SharedAccessKey=<device_key>"                */

/*  "HostName=<host_name>;DeviceId=<device_id>;SharedAccessSignature=<device_sas_token>"    */



//Connection String to interface your device with IoT hub

static const char* connectionString = "";


//JSON data to transmit Weather readings
const char *messageData = "{\"deviceFormat\":\"%s\",\"deviceId\":\"%s\", \"messageId\":%d, \"TemperatureF\":%.2f, \"Humidity\":%.2f, \"TemperatureC\":%.2f, \"Pressure\":%.2f}";




//variable to keep the count of msg delivered

int messageCount = 1;

static bool messageSending = true;


int k = 10;

int i;



//variable to store temp,humid,press

static float humidity; 

static int16_t cTempint; 

static float cTemp;

static float fTemp;

static float Press;



//Callback to check the confirmation frome azure

static void SendConfirmationCallback(IOTHUB_CLIENT_CONFIRMATION_RESULT result)

{

  if (result == IOTHUB_CLIENT_CONFIRMATION_OK)

  {

    Serial.println("Send Confirmation Callback finished.");

  }

}



//payload callback

static void MessageCallback(const char* payLoad, int size)

{

  Serial.println("Message callback:");

  Serial.println(payLoad);

}



static void DeviceTwinCallback(DEVICE_TWIN_UPDATE_STATE updateState, const unsigned char *payLoad, int size)

{

  if(updateState){

     char *temp = (char *)malloc(size + 1);

  if (temp == NULL)

  {

    return;

  }

  memcpy(temp, payLoad, size);

  temp[size] = '\0';

  // Display Twin message.

  Serial.println(temp);

  free(temp);   

    }

    else{

          Serial.println("Device State not updated");

      }

}


void setup()

{

  //Start serial communication
   Serial.begin(115200);
  
  // Start the I2C Comunication
  Wire.begin();
  
  // Start the  SW01 Sensor
  SW01.begin();


  while(!Serial);


  // Initialize the WiFi module

  Serial.println(" > WiFi");
  InitWifi();

  

  Serial.println(" > IoT Hub");

   Esp32MQTTClient_SetOption(OPTION_MINI_SOLUTION_NAME, "GetStarted");
   
  //Connect to IoT Hub
  Serial.println(Esp32MQTTClient_Init((const uint8_t*)connectionString, true, true) ? "Connected to IoT Hub" : "Error Connecting to IoT Hub");

  

  //Set different callbacks

  Esp32MQTTClient_SetSendConfirmationCallback(SendConfirmationCallback);

  Esp32MQTTClient_SetMessageCallback(MessageCallback);

  Esp32MQTTClient_SetDeviceTwinCallback(DeviceTwinCallback);

}



void loop()

{
  
  //Create message payload
  char messagePayload[MESSAGE_MAX_LEN];

  //Poll SW01 sensor
  SW01.poll();

  Press=SW01.getPressure()/1000;

  humidity = SW01.getHumidity();

  cTempint = SW01.getTempC();

  cTemp = (float)cTempint;

  fTemp = cTemp * 1.8 + 32;

  Serial.print("Atmospheric Pressure :");
  
  Serial.print(Press);

  Serial.println(" kPa");

  Serial.print("Relative Humidity :");

  Serial.print(humidity);

  Serial.println(" %RH");

  Serial.print("Temperature in Celsius :");

  Serial.print(cTemp);

  Serial.println(" C");

  Serial.print("Temperature in Fahrenheit :");

  Serial.print(fTemp);

  Serial.println(" F");

  if(millis()-msg_Timer> msg_Interval){

      msg_Timer= millis();

      Serial.println("Sending Message");

      String deviceFormat = "realValues"; 

      

      //snprintf stores the data in char buffer

      //snprintf(char buffer,  size of buffer,   format,         arg1,      arg2,        arg3,       arg4,  arg5,    arg6,  arg7)

      snprintf(messagePayload,MESSAGE_MAX_LEN, messageData, deviceFormat.c_str(), DEVICE_ID, messageCount++, fTemp,humidity,cTemp,Press); 

      Serial.println(messagePayload);

      

      //create an event MESSAGE(message) to send the buffer(messagPayload) to Azure  

      EVENT_INSTANCE* message = Esp32MQTTClient_Event_Generate(messagePayload, MESSAGE);

      

      //send the event to azure

      Esp32MQTTClient_SendEventInstance(message); 

      delay(50);   

  }

else{
      Esp32MQTTClient_Check();
    }

}



void InitWifi(){

  

    Serial.println("Connecting...");

  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {

    delay(500);

    Serial.print(".");

  }

  

  Serial.println("WiFi connected");

  Serial.println("IP address: ");

  Serial.println(WiFi.localIP());

  }