By knowing what frequency the AC electricity in your house runs at, my Arduino can guess what countries you're NOT in. Sketch with explanation: gist.githubuse...
Actually, this is rather interesting. Although I have done experiments with antennas on analog inputs, I never really realized just how well it can pick up the ac mains signal. Hmmmmm wondering if I could get away with NOT using an RTC or an oscillator, instead syncing timebase against mains...
