Bluetooth low energy (Smart) Heart rate variability sensor demo app for Android
This app searches for nearby BLE devices and connects to heart rate sensor service. It shows hear rate (average pulse) and heart rate variability (beat-to-beat interval or RR data). The app also has a graphical demo of pulsing dot for real-time biofeedback monitoring of hear rate variability showing nicely how breathing rate affects heart rate variability.
Heart rate variability could be used to calculate different things like training effect on sports, sleep quality, stress and relaxation effects since it mirrors parasympathetic nervous system activity.
BLE is a nice since it has open protocol for transmitting data like heart rate here. It makes setting up a development environment relatively fast and you can concentrate on doing you actual business logic.
Bluetooh BLE is supported from Android 4.3 (API level 18) onwards. Read more about Android BLE development. There is also Android sample code for GATT services.
- Tested heart rate belts:
- Polar H6
- Android BLE devices:
- Nexus 7 (Asus)
Install the app from Google Play Store
Connect heart rate BLE belt on your chest or wrist. Start the app and scan for BLE devices. Select heart rate sensor and wait for the GATT hear rate service to be found. Heart rate data values starts to update on the screen. Press demo button to show a graphical demo of heart rate variability. You will get nice graphics when you sit down relaxed. Try some slow deep breaths. The dot shows your heart rate variability cut from 700 milliseconds corresponding to pulse of 87. If your pulse is higher no dot is drawn. You can select GATT information services to read other data on the device.
Android BLE seems to be slow to connect on first time. Please wait a minute or two to get the heart rate reading. If device is disconnected some times switching Android bluetooth off and back on will help to reconnect. Make sure your chest belt is well moisturized to get a good contact.
- Olli Erjanti - olli@erjanti.fi
Most of the bluetooth BLE sensor handling are from TI Sensor Tag project by:
- Steven Rudenko - steven.rudenko@gmail.com
Polygon drawing from Pro Android book by APress and Sayed Hashimi and Satya Komatineni.
The MIT License (MIT)
Copyright (c) 2013-2014 Steven Rudenko and Olli Erjanti
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