BLE Heart rate variability

BLE Heart rate variability demo

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 heart 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.

This is an open source demo project for developers to start experimenting with BLE heart rate sensor development.
The source code can be found in github:
https://github.com/oerjanti/BLE-Heart-rate-variability-demo

Use instructions
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.

Troubleshooting
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.