How To Build Your Own Activity Tracker

PSFK by Macala Wright




The wearable technology market has experienced expansive growth in the past three years when it comes to health. But for those that don’t already own them, cost of ownership is cited as a major barrier to adoption. So the question becomes, would more Americans adopt health related wearables if they were cost effective or they could even make the devices themselves? So how does one go about making their own activity tracker? According to RetroBrand, on open source Arduino Wearable Project, it’s not that complicated.

The rise of DIY wearables has been happening for over a decade; consumer use has just increased the pace at which the field is developing. From DIY wearables to high-tech sensors and smart fabrics, a simple google search shows you how to make just about anything.

The RetroBand “smart band” activity tracker has only one feature, which is collecting data by using an accelerometer and sending it to a mobile device. Then the mobile device calculates the calories and steps by using the data. In order for this project to work, you have to buy a battery, a Bluetooth module and an accelerometer. You’ll also have to download some custom software on your smartphone from Google Play.

RetroBand consists of an Arduino part and an Android app. The Arduino has four main parts: an Arduino board, accelerometer, Bluetooth module, lithium-polymer battery. The Android app contains of four parts: Android UI, Bluetooth manager, Algorithm section, background service.



If Arduino powers on and the pairing process with RetroBand app is done, the board checks the accelerometer data 20 times every second.

The Android app receives the data during two seconds and finds out an interval that user’s movement increase dramatically. The number of user’s movement increase is user’s a step count. The app calculates burned calories based on user’s weight and steps, and accumulates data monthly, daily and hourly.

Overall, the algorithm of the app is not that complicated. If the developer is experienced enough, they use their own algorithm. One drawback is that RetroBand Arduino cannot save the data itself due to limited memory capacity and only works when it’s connected with a mobile device.

Want to build your own tracker? Download the complete instructions here.