BLE Heart Rate

Plot output from multiple bluetooth heart rate sensors on the same graph using just javascript.

The processing is all html and javascript - no cookies or server side processing. It requires chrome or edge on windows and a bluetooth adapter or chrome beta on linux with experimental features turned on (om my 10 year old laptop connecting to ble sensors causes wifi to disconnect). If it doesn't work check the console..

Tested with all 3 ble heartrate devices that I own all connected at once.


[connect] as many times as you have heart rate sensors that you want to graph
[start recording] - [stop recording] - this will generates a csv file with spreadsheet timestamps when you hit stop. Not required unless you want a record
"Graph updates on" - the graph can be zoomed - this checkbox pauses updates that otherwise reset the zoom when the graph is refreshed every 2 seconds

- I haven't figured this out yet - loading files after clearing will fail so reload the page to reset.

Upload/input multiple files

You can also input multiple gpx files and display them on the same map and compare heart rate data and pace.

They need to be close in time and space


Make a downloadable tcx file - can be uploaded to strava. Allow upload and parsing of gpx files that will be added to the graph (and map). What other formats? Add a map to display gpx