Mercury Droid is one kind of IoT(Internet of things) based "Home Weather Monitoring" Android mobile application. this application is capable of read home weather activity like Celsius, Kelvin, Fahrenheit, Heat-Index, Humidity. Basically this application can communicate with NodeMCU(ESP-8266MOD), which is and IoT wifi Module. the NodeMCU(ESP-8266MOD) is the brain of Mercury Droid IoT Embedded system which collect DHT-11 sensor Temperature and Humidity data send this sensor data to it's Webserver and then Mercury Droid android mobile application can read this data from NodeMCU(ESP-8266MOD) or Mercury Droid webserver by using a specific static IP address. By default this static IP is 192.168.0.107 . this application has also have a special feature to measure the excessive Temperature by comparing with user given Threshold value. If the threshold value is less than Celsius Temperature value than this application gives you alert if Threshold value is grater than Celsius value it not gives you alert.

You can build whole system from here :
https://www.instructables.com/id/IoT-Home-Weather-Monitoring-System-With-Android-Ap/

Mercury Droid or NodeMCU(ESP-8266MOD) System Arduino IDE Code :
https://github.com/avimallik/IoT-Home-weather-monitoring-system-NodeMCU-ESP-8266MOD-Code

Basic Information :
Mercury Droid Application can communicate with Mercury Droid System by using this Static IP Address : 192.168.0.107 . You can change this IP address from NodeMCU code

Hardware or Instruments I used :
1. NodeMCU(ESP-8266MOD)
2. DHT-11 Temperature & Humidity Sensor