To train Keen initially, the Keen app will need to be downloaded on your mobile device.  Once trained, Keen becomes a standalone device and a constant Bluetooth connection is not required.  For example, a parent can help a child set up Keen using the parent's mobile device, and then the child can wear Keen to school without bringing the mobile device along.  When Keen and the mobile device are back in range of each other, Keen can be synced to the app and you can view the "Me Screen" in the app to view your weekly and daily behavior patterns.