I'm guessing that probably nobody will find these usefull, but here they are just in case.

Two simple progs: ac and dc. The ac program reads /proc/empeg_power and returns true if the empeg is on ac and false if it's on dc. The dc prog is the other way 'round.

Why? It's less CPU and RAM overhead than grep "Power)" /proc_empeg_power | grep -c AC.