Hardware
1. Arduino Mega ADK
2. Wifi-shield
3. Mega Sensor shield
4. Wifi Module
Tinker-kit also comes with several micro mechanical sensors such as accelerometer, photo-resistor, among others. Each sensor can be connected to the Mega sensor shield in order to sense environmental data.
Software
Configure Wifi Module and Establish Android Communication
Once you established communication with Android, then you are ready to start developing Arduino sketches and your Android app.
Here some code to try