Sleeping device...

One an infomercial a while ago i saw this device that you wore while you were sleeping. It was a headband mask kind of thing, and it detected when you fell asleep. Now when you fell asleep, it somehow got the message through to your brain that you were sleeping, so that in your dream, you knew it was a dream.
Anyone know what im takling about?
if so, know any place on the net where i could buy one?

Try here.