   #include <DHT_linkit.h>     // Reference: https://github.com/Seeed-Studio/Grove_Starter_Kit_For_LinkIt/tree/master/libraries/Humidity_Temperature_Sensor
   #include <Digital_Light_TSL2561.h>  // Reference:  http://www.seeedstudio.com/wiki/Grove_-_Digital_Light_Sensor
   #include <HP20x_dev.h>      // Reference: http://www.seeedstudio.com/wiki/Grove_-_Barometer_(High-Accuracy)
-
+  #include <KalmanFilter.h>
+  
   #define DHTPIN 2     // what pin we're connected to
   #define DHTTYPE DHT22   // DHT 22  (AM2302)
   DHT_linkit dht(DHTPIN, DHTTYPE);
   unsigned char ret = 0;
+  KalmanFilter t_filter;    //temperature filter
+  KalmanFilter p_filter;    //pressure filter
+  KalmanFilter a_filter;    //altitude filter
 #endif
 
 #define SENSOR_ID_RECORDID 0

#define MQTT_PROXY_IP "gpssensor.ddns.net"  // Current LASD server
#define DEVICE_TYPE  "LinkItONE"
//#define DEVICE_ID "LASS-Example"    // REPLACE: The device ID you like, please start from LASD. Without this prefix, maybe it will be filter out.
//#define MQTT_TOPIC_PREFIX "LASS/Test" 
//#define PARTNER_ID "LASS-Partner1"
#define DEVICE_ID "LASS-MAPS-LJ"    // REPLACE: The device ID you like, please start from LASD. Without this prefix, maybe it will be filter out.
#define MQTT_TOPIC_PREFIX "LASS/Test" 
#define PARTNER_ID "LASS-Partner3"
char mqttTopic[64];
char mqttTopicSelf[64]; // The topic used for central alarm
char mqttTopicPartner[64]; // The topic used for partner alarm

          0: record_id, 1: battery level, 2: battery charging, 3: ground speed ( Km/hour ) 
        Default user sensor order:
          10: dust sensor, 11: UV  sensor, 12: sound sensor 
        Default user sensor order in APP-3 (MAPS):
          10: barometer sensor (high accuracy), 11&12: temperature & humidity sensor pro, 13: digital light sensor
        
        Original:
          The idea come from here: http://iot-hackseries.s3-website-us-west-2.amazonaws.com/linkitone-setup.html
