communication between android phone and Fitbit devices

Question

How Connection between Android Phone and FitBit devices is performed?? I know they are using BLE,In this case how BLE is working??

Is there any documents which clear the concept of FitBit working?

Please Help.thanx

Answer 1

There is no documentation (and probably will never be) on the communication between a device and the fitbit tracker. This communication happens on a Bluetooth LE level, using proprietary commands.

On a regular basis, all trackers in the vicinity are listed ('discovered') by the phone. The trackers then indicate what their ID is, and if they have been recently synchronised (~15min.). In case they have not been recently synchronised, the device establish a connection with the tracker (using the tracker ID), upload its data to the fitbit server, and erase it from the tracker.

By reverse-engineering logs, we wrote galileo a free utility that allow you to synchronise your tracker, pair a new one, or (soon) perform a firmware update using their dongle. Feel free to study the source code to learn more about the communication.