Zeo Sleep Manager
The Zeo Sleep Manager is an electroencephalograhy(EEG)-based sleep tracker as well as smart alarm. It uses three sensor pads made of conductive fabric on a headband, which is connected to a device to measure the brain signals. The headband was meant to be replaced once in every three months or so, and Zeo, Inc. sold replacement headbands as a part of its business strategy. However, the company went bankrupt in 2013, and as such these replacements are no longer available.
At present, all variations of the Zeo is only available second-hand. There has been a steady, albeit low, supply of new-in-box Zeos on Ebay.
Its first variation, with a physical smart alarm set and requiring an SD card to store the data, was launched in 2009. In 2011, the Zeo Mobile was launched. Unlike its predecessor, it does not have a dedicated physical alarm system but instead uses a smartphone app to synchronize the data and provide the alarm capability.
The Zeo is considered to be a reliable way to measure polyphasic sleep adaptation progress. According to a study, the Zeo is between 78.9% to 83.5% accurate when compared to a PSG, the gold standard in sleep measurements. This sets it apart from most consumer-grade sleep tracking products, which have very poor performance and are not considered useful.