ARDUIO

http://www.arduino.cc/
https://www.sparkfun.com/search/results?term=gas+sensor

2.4Ghz

https://arduino-info.wikispaces.com/Nrf24L01-Info

GSM

https://www.circuitsathome.com/mcu/programming/interfacing-arduino-to-a-cellular-phone

SENSORS

http://www.instructables.com/id/Use-your-android-phone-sensors-on-the-arduino-/

Linux

https://wiki.archlinux.org/index.php/arduino

Bluetooth:

http://homepages.ihug.com.au/~npyner/Arduino/GUIDE_2BT.pdf

433

http://code.google.com/p/rc-switch/
http://www.wes.id.au/2013/07/decoding-and-sending-433mhz-rf-codes-with-arduino-and-rc-switch/

Time

http://playground.arduino.cc/Code/Time#.UzVmHqYX5CM
http://arduino.cc/en/Tutorial/UdpNtpClient
NTP server

power save

http://playground.arduino.cc/Learning/arduinoSleepCode#.UzVn06YX5CM