An app to help you get a better night's sleep

Another idea I had on the go today. This one is for an app that uses your camera to help you get a better night's sleep. Here's how it works. You put the app on your bedside table, plug it in, and turn it on. It keeps taking photos of you as you sleep and uses the position of your head to make sure that you've had a good night's sleep. If your head has been in the same position for, for example 7 hours, you will get a notification saying '7 hours' when you wake up.