The Zeo Personal Sleep Manager is a mains powered bedside alarmclock that records the most comprehensive data on sleep activity of any of the sleep monitoring devices I have tested. In addition to being the most expensive, it is also one of the more intrusive in that it requires the user to wear an elasticated headband while sleeping:
While the other sleep monitoring devices rely on the relatively imprecise science of actigraphy, this device uses proprietary technology to apparently monitor brain activity using a simplified form of electroencephagraphy, although this is only a guess. I have attempted to determine if the device is simply measuring heart rate, movement or some other metric by wearing it on my arm instead of my forehead but it didn’t record any data so I have no reason to doubt that it is measuring some kind of brain activity.
The main part of the system is the bedside digital clock which also stores and charges the headband when not in use:
In common with the other sleep logging systems, the clock allows you to set a desired wake time and will wake you before the wake time if you enter a light sleep phase in order to prevent you having to be awkened (groggy) from a deep sleep phase later. The data is stored on an SD card. In order to get at the data you need to remove the card, connect it to a computer, log into the zeo website, then upload the data from the card. Here is a basic view from the website:
and you can examine an individual night to look at the apparent level of sleep (based on brain activity?) so you can see how long you were in each of the four stages of sleep:
There are now smaller versions which connect to a smartphone app instead of using a less portable alarm clock, but at between $100 and $200 this is an expensive solution and some users find the headband uncomfortable or difficult to get to sleep with (besides looking a little silly).
On the plus side, the manufacturer provides free unlimited access to your own data on their website after you have bought the product and they allow you to export your own data in an open format, so once you have bought the device there are no other costs. On the downside the device isn’t Internet enabled so you have to manually move the SD card and go through an upload process when you want to get at your data. The newer mobile version which connects to a smartphone doesn’t appear to have this limitation but I haven’t evaluated it. I’m also impressed with the way the company seems commited to keeping all the data open and letting people hack it. Brian Schiffler hacked the Zeo to produce real time brain activity data and Zeo hired him as an intern to make the data more open.