Android Sleep measurement app

I require an app to measure the sleeping? pattern? of an individual, or couple. It will graph the results and offer a history of sleeping. Dev must have android experience. Must demonstrate and example of previous work. Examples of existing software to use as reference; <[login to view URL]> and <[login to view URL]> ## Deliverables Main concerns with the project; Android phones put the accelerometers to sleep when screen is off Battery life while program runs over night Accuracy? of the graph must be high Graphics must match the Android OS Targetting devices; Nexus One HTC Desire HTV Evo Samsung Galaxy S Preferable if you own one of these for testing.