Wireless rf solution should be kind of easy job to add. You can use example these kind of 433Mzh transmitters / receivers. http://randomnerdtutorials.com/rf-433mhz...h-arduino/
Edit: Nevermind :D I forget little thing. If you use those kind of transmitters / receivers, you must put additional arduino inside power bar :D Not so good idea :D
Edit: Nevermind :D I forget little thing. If you use those kind of transmitters / receivers, you must put additional arduino inside power bar :D Not so good idea :D
