I would like to turn on my car's heated seats over a mobile/cellular network using my iPhone, and I'm trying to figure out the simplest path. I know very little beyond that goal, but I know that RF, ...

In this quick Arduino tutorial I will explain how you can control a relay using the Arduino Board, one 1K and one 10K resistors, 1 BC547 transistor, one 6V or 12V relay, one 1N4007 diode and a 12V fan ...