Custom Firmware Unlocks Fitness Tracker

July 3, 2016 by Elliot Williams 17 Comments

[Mikhail] sent us a teaser video for a hack he’d done (embedded below). He takes a Bluetooth LE fitness tracker dongle and reflashes it spit out the raw accelerometer data and trigger events. He then wrote a phone app that receives the data and uses the device as an alarm, an on/off switch, a data-logging device, and more.

We thought it was cool enough that we asked [Mikhail] for more detail, and he delivered in spades! Inside the device is a Nordic NRF51822, their ARM Cortex + Bluetooth chip, an accelerometer, and a bunch of LEDs. [Mikhail] mapped out the programming headers, erased the old flash, and re-filled it with his own code. He even added over-the-air DFU re-flashing capability so that he wouldn’t have to open up the case again.

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Homemade Activity Monitor

September 1, 2014 by Matt Terndrup 13 Comments

A group of developers have uploaded a tutorial on Instructables showing the steps needed to develop a homemade DIY fitness tracker. The design is the second iteration of an Arduino-based wearable smart watch project of theirs. This time around, they opted to focus more on the monitoring system rather than a visual display. It is called the ‘RetroBand’ and records steps taken and calories burned by the user.

The microcontroller used is an Arduino Pro mini 3.3v. Accelerometer and gyro sensors were integrated to capture the movement of the ‘RetroBand.’ A wireless bluetooth module connects to an Android phone which presents the data through a Play Store app complete with graphs included. An enclosure was 3D printed. Everything is powered by a one cell Lithum-Polymer battery. The code for the project can be found on Github, and additional information with a how-to manual is on their website (which is in Korean, but can easily be translated through the browser).