Mobile World Congress 2014 offers a look at the Sony take on fitness trackers first announced at CES 2014-- specifically the Core, an activity sensor slotted inside the SmartBand (SWR10) bracelet.
The Core pairs with Android smartphones and Sony-developed fitness app Lifelog. Unlike similar offerings from Jawbone and Nike, the Core allows wearers to keep track not only of physical activities and sleep patterns, but also of communications, places visited and entertainment. In other words it provides (wait for it) a log of one's life.
While not an actual "smart" device, the Core also vibrates to let users know of received messages or alarms.
Designed to be worn 24/7, the Core communicates with smartphones via Bluetooth or NFC and tracks activities even when out of range from a paired device. It is waterproof is easily removed from the included rubber strap.