RetroBand is the second result of Arduino Wearable Project that is supported by open source. I think this shouldn’t be called a ‘smart band’ since it has only simple features. Actually, it’s rather to be called an “Activity Tracker”… But the term ‘smart band’ is more familiar to me, so I just call it a smart band. The important thing of smart bands is they are connected with mobile devices by Bluetooth and track the daily routine of users.
RetroBand that is implemented by Arduino has only one feature, which is collecting data by using accelerometer and sending them to a mobile device. Then the mobile device calculates the calories and steps by using the data. The feature is simple, and that means the structure of this device is way simpler than RetroWatch, so it’s very easy to make it in your own taste.
The android app check steps using collected data provided from RetroBand Arduino. The algorithm of the app is not that complicated. If you have much experience to this area, you can replace it with your own algorithm. The app saves the calorie data, so you can see the progress it in a monthly/daily/hourly graph form. FYI, RetroBand Arduino cannot save the data itself since the shortage of its memory capacity. That is, it only works when it’s connected with a mobile device, which means you cannot collect the data with RetroBand Arduino only. I think this problem will be fixed when Arduino gets improved.
RetroBand consists of an Arduino part and an Android app.
The Arduino has 4 main parts – Arduino board, accelerometer(MPU-6050), Bluetooth module(HC-06), lithum-polymer battery(charge board is optional).
The Android app contains of 4 parts – Android UI, Bluetooth manager, Algorithm section, background service.
If Arduino powers on and the pairing process with RetroBand app is done, the board check the accelerometer data 20 times in every 1 second. And it transfer the data to the mobile device once a second. The accelerometer measures x axis / y axis / z axis values, so the band sends 60 values(20 times x 3 axis) of data to the device. 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 calculate burned calories based on user’s weight and steps, and accumulates data monthly, daily and hourly.