Smart Sleepers

New Scientist: Are you a real grump in the mornings? Do you wake up every day feeling tired, embittered, aggrieved, and all too ready to hit the snooze button? If so, then a new alarm clock could be just for you.
The clock, called SleepSmart, measures your sleep cycle, and waits for you to be in your lightest phase of sleep before rousing you. Its makers say that should ensure you wake up feeling refreshed every morning.
As you sleep you pass through a sequence of sleep states – light sleep, deep sleep and REM sleep – that repeats approximately every 90 minutes. The point in that cycle at which you wake can affect how you feel later, and may even have a greater impact than how long or little you have slept. Being roused during a light phase means you are more likely to wake up perky.
The clock that wakes you when you are ready [New Scientist]