I had a Zeo for awhile. It does a pretty good job, but it was disturbing how locked-in your data was. There are smartphone apps that will also gather comparable data for much less:
http://lifehacker.com/5441045/sleep-cycle-analyzes-your-sleep-patterns-for-a-better-wake+up
Also, if you snore, then blood oxygenation level is not a bad proxy for sleep, and clinical quality devices are available on ebay for much less than a new Zeo.
ZEO isn't locked in at all anymore- they have a decrypted firmware you can download, an open source library for interfacing the data format, as well as instructions online to interface the ZEO directly via a serial port if you want realtime data.
You can now use the ZEO without even ever uploading the data to their website.
I'm thinking that it should be possible to decide when to sleep based on reduced performance.
Can anyone suggest a tool for that purpose? Perhaps some reaction time testing software?
I guess I would have to track myself during the day to make a baseline, which is fine.
But without some sort of test I end up staying up way pass effectiveness, which is a waste of my time.
-Robin