How do Nike shoes communicate with your ipod?

We've all seen those Nike + things that can tell you how far you've run and how fast and can track your run. How do they communicate with your ipod? Is it through bluetooth and you have to use an adapter in your ipod? Also, how reliable is it? I know it's probably not as good as a gps system, but is it still pretty good?|||it works fairly accurately once you get it calibrated. there is a sensor that is plugged into the ipod and one that goes in your shoes. it counts your steps and calculates the distance. the reason they are not accurate if if you take a shorter or longer step that you calibrated it for, it can not measure it. it measures each step at the same distance. Yes you can track your run, it tells you on the IPOD or you can download it to the NIKE plus website where they have a running log. it will tell you your pace while running if you want.


The system is called a NIKE + kit and it costs about $30.00. I had one until I bought a GPS and it was anywhere to .2 to .6 of a mile off|||You have to buy a ipod kit for them