home automation uses a gas sensor-Group B- By Lavin 

Automation Sensors are the eyes and ears of your home. Automation Sensors take control of your lights and appliances so you can customize how and when to control devices around your home. Electrochemical gas detectors allow gases to diffuse through a porous membrane to an electrode where it is either chemically oxidized or reduced. 

The LCD & keypad shield in Arduino-Group B- By Lavin 

The LCD shield supports contrast adjustment and backlit on/off functions. It also expands analog pins for easy analog sensor reading and display. The LCD Keypad shield is developed for Arduino-compatible boards, to provide a user-friendly interface that allows users to go through the menu, make selections, etc.

 Arduino works as an earthquake detector-BY SHIRWAN 

In this way, acceleration is detected by the accelerometer and simultaneously by the Arduino ADC pin. If the motion is violent enough during an earthquake and crosses the threshold value alarm light LED glows, and a buzzer sounds as an indicator of the earthquake in the core of the land where the building is situated.