# Bluetooth Heart Rate Monitor

When this app is installed it overrides Bangle.js's build in heart rate monitor with an external Bluetooth one.

HRM is requested it searches on Bluetooth for a heart rate monitor, connects, and sends data back using the `Bangle.on('HRM'` event as if it came from the on board monitor.

This means it's compatible with many Bangle.js apps including:

* [Heart Rate Widget](https://banglejs.com/apps/#widhrt)
* [Heart Rate Recorder](https://banglejs.com/apps/#heart)

It it NOT COMPATIBLE with [Heart Rate Monitor](https://banglejs.com/apps/#hrm)
as that requires live sensor data (rather than just BPM readings).

## Usage

Just install the app, then install an app that uses the heart rate monitor.

Once installed it'll automatically try and connect to the first bluetooth
heart rate monitor it finds.

**To disable this and return to normal HRM, uninstall the app**

## Compatible Heart Rate Monitors

This works with any heart rate monitor providing the standard Bluetooth
Heart Rate Service (`180D`) and characteristic (`2A37`).

So far it has been tested on:

* CooSpo Bluetooth Heart Rate Monitor

## Internals

This replaces `Bangle.setHRMPower` with its own implementation.

## TODO

* Maybe a `bthrm.settings.js` and app (that calls it) to enable it to be turned on and off
* A widget to show connection state?
* Specify a specific device by address?

## Creator

Gordon Williams