ThingsBoardClient.ino

#include <SPI.h>
#include <Ethernet.h>
#include <PubSubClient.h>
#include <dht.h>

// Update these with values suitable for your network.
byte mac[]    = {  0xDE, 0xED, 0xBA, 0xFE, 0xFE, 0xED };
IPAddress ip(192, 168, 1, 5);
IPAddress server(192, 168, 1, 2);

// YL-39 + YL-69 humidity sensor
byte humidity_sensor_pin = A1;
byte humidity_sensor_vcc = 7;

#define DHT11_PIN 6   
#define AUTH_TOKEN "1a3XZV0Tc17lkA7DkdKO" // ThingsBoard Device Auth Token

dht DHT;

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  for (int i=0;i<length;i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();
}

EthernetClient ethClient;
PubSubClient client(ethClient);

void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Attempt to connect
    if (client.connect("arduinoClient", AUTH_TOKEN, NULL)) {
      Serial.println("connected");
      // Once connected, publish an announcement...
      client.publish("v1/devices/me/attributes","{\"firmware_version\":\"1.0.0\", \"serial_number\":\"ThingsBoardClient-001\"}");
      // ... and resubscribe
      //client.subscribe("inTopic");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}

void setup()
{
  Serial.begin(57600);

  // Init the humidity sensor board
  pinMode(humidity_sensor_vcc, OUTPUT);
  digitalWrite(humidity_sensor_vcc, LOW);

  client.setServer(server, 1883);
  client.setCallback(callback);

  Ethernet.begin(mac, ip);
  // Allow the hardware to sort itself out
  delay(1500);
}

int read_humidity_sensor() {
  digitalWrite(humidity_sensor_vcc, HIGH);
  delay(500);
  int value = analogRead(humidity_sensor_pin);
  digitalWrite(humidity_sensor_vcc, LOW);
  return 1023 - value;
}

void loop()
{
  if (!client.connected()) {
    reconnect();
  }
  int chk = DHT.read11(DHT11_PIN);
  switch (chk)
  {
    case DHTLIB_OK:  
                Serial.print("OK,\t"); 
                break;
    case DHTLIB_ERROR_CHECKSUM: 
                Serial.print("Checksum error,\t"); 
                break;
    case DHTLIB_ERROR_TIMEOUT: 
                Serial.print("Time out error,\t"); 
                break;
    case DHTLIB_ERROR_CONNECT:
        Serial.print("Connect error,\t");
        break;
    case DHTLIB_ERROR_ACK_L:
        Serial.print("Ack Low error,\t");
        break;
    case DHTLIB_ERROR_ACK_H:
        Serial.print("Ack High error,\t");
        break;
    default: 
                Serial.print("Unknown error,\t"); 
                break;
  }
  String json = "{\"temperature\":"+String(DHT.temperature, 2)+", \"humidity\":"+String(DHT.humidity, 2)+", \"moisture\":"+read_humidity_sensor()+", \"active\": false}";
  char buf[json.length()+1];
  json.toCharArray(buf, json.length()+1);
  client.publish("v1/devices/me/telemetry", buf);
  Serial.print("Data Sent : ");
  Serial.println(buf);
  delay(5000);
  client.loop();
}