Bangle.js 2 Cutting Edge - new heart rate algorithm

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user140377
If you want to compare the Bangle.Js please only compare it to a chest belt like the "Polar H10" mentioned above. All wrist measurement devices do lie you can not decide for each indidivual which one does lie more without a reference measurement.

@adjtm
To be honest this is the dirty part which can be improved, it is the following code:
```
const file = require("Storage").open("hrmlog.json","w");
Bangle.setHRMPower(1);
Bangle.setBTHRMPower(1);

Bangle.on('HRM', (hrm) => {
    console.log(hrm);
    const json = JSON.stringify({now: new Date(), hrm: hrm});
    file.write(json + ",\n");
});

Bangle.on('BTHRM', (hrm) => {
	if (hrm.bpm > 0) {
		console.log(hrm);
		const json = JSON.stringify({now: new Date(), bthrm: hrm});
		file.write(json + ",\n");
	}
});
```
The json is converted to csv and then given to PlotJuggler.
Next time I will change this to record in csv so no conversion is required.
bthrm must be configured not to overwrite the internal measurement.

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fanoush in reply to @user140377

If you want to compare the Bangle.Js please only compare it to a chest belt like the "Polar H10" mentioned above. All wrist measurement devices do lie you can not decide for each indidivual which one does lie more

Well Bangle.js is also wrist measurement device :-)
Yes they have their issues, major one is that any movement distorts the data a lot. However when sitting still I'd say in principle there is no reason for them to not work, the beats are there in the data to see, it is no magic (unlike blood pressure or other stuff). Also in my case all other devices basically agreed what my pulse is +-1 it was only Bangle2 that was off. Yesterday I retried again with other devices (ID130Plus HR, Kospet DK08, ID107HR Plus all with their original firmware) and it was quite the same, once I was not moving and gave it like 5-10 seconds they all stabilized on some number +-1 and slowly drifted as my pulse changed and bangle2 was mostly lower by ~10. I tried to arrange some photo/video but then gave up, it is hard to keep two hands still with all displays visible and make a photo :-)

BTW it feels to me that initially the difference is not so high but once stuff settles after few seconds Bangle2 drifts down and stays there. It was also interesting that the confidence varies even if sitting still, I see nice regular bumps drawn and then it draws basically flat line and then it 'refocuses' and is OK again. Can't match it to my movements (tried to not move at all of course). And it is off by ~10 even when I see those nice regular bumps (and confidence 100%).

I used the Heart Rate Monitor (v0.11) app
https://github.com/espruino/BangleApps/tree/master/apps/hrm
FW was 2v17.109 http://www.espruino.com/binaries/travis/d7e760bc7896eb15a875d5ea2c43dfa8900643e6/

The most interesting to me is that one of the watches is Q3 = same hardware as Bangle2 with firmware that may even have same HR library linked inside. I also tried to switch hands of course.

Bangle.js 2 Cutting Edge - new heart rate algorithm

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