Sample rates of iFeel and Biosignals HS sensors.

[Richard]

I am getting very different Smoothness readings between my iFeel and BioSignals HS hardware in Alive Pioneer.

My iFeel Sensor Report: All - Ave Smoothness 70% (Smoothness Difficulty: Challenging)
My BioSignals HS Report: All - Ave Smoothness 26% (Smoothness Difficulty: Easy !)

The iFeel USB Sensor is listed as 200 samples per second at https://www.somaticvision.com/iFeelUSB
I understand that the Biosignals HS controls the heart rate sensor very differently and I am wondering what the sample rate is?

I would never compare results between my dear old 30Hz HeartMath emWave sensor and my 200Hz iFeel sensor.
So I'm wondering if I'm comparing 'apples to oranges' by comparing my 200Hz iFeel sensor to my ? Hz BioSignals HS sensor?

With Thanks,
Richard.

[Richard]

After writing the post above, I did a 20 minute session using the BioSignals HS sensor and scored an Average Smoothness of 92% - which represents my highest score ever using my BioSignals sensor. )

My Average smoothness score from my last BioSignals HSW session a few days ago was 36%.
What am I missing here, I wonder...?

Am still interested to know the sample rate of the BioSignals HS sensor, please.
R.

[Ryan Deluz]

The BioSignals sensor also has 200 samples per second of BVP (heart rate).

Perhaps you don't always have a good signal? Or you were just more stressed during that session / those sessions for some reason.

Open a secondary graphing screen and choose the BVP Signal Quality Test screen. Take a look at the waveform, and the marked heart rate lines (a line is shown for each beat detected, with a number above with the heart rate detected for that beat).

Do the signal for the BioSignals looks clean, with accurately detected heartbeats? If so, then it is accurately measuring your heart rate, and the difference cannot be because of the sensor. Leave that screen open in the background while you are training, you may notice that you move and generate an error, etc.

Which sensor are you using with the BioSignals HS (which heart rate sensor)?

[Richard]

Thanks for your quick response, Ryan.

Intersting that they are both 200 samples per second.
Generally the HS BioSignals reports more HF in the Frequency Spectrum graph compared to the iFeel for me - so I assumed the BioSignals sample rate must be higher / more accurate.
I am using the grey rubber HR sensor with both the BioSignals HS and iFeel.

Rather than go down a rabbit hole at this stage, I'll make 2 new users for myself - a HS Biosignals user and an iFeel user.
I'll use the same grey rubber HR sensor in every session, check that all the Control Panel settings and difficulty settings are the same, and do 10 sessions on each user/device and report back.

Cheers,
Richard.

[Ryan Deluz]

Hi Richard,

What you should really do is set up two computers with Alive, then measure a single session where you are being recorded by both sensors, then take a look at what is shown.

Above 200 samples per second for BVP doesn't mean much, the blood vessels don't expand/contract fast enough to make a higher sampling rate meaningful I am told.

The BioSignals device uses a Somatic Vision algorithm to determine the heart rate, whereas the iFeel device uses the hardware manufacturer's algorithm. In either case, the only way to really tell is to record from both devices on the same hand at the same time (perhaps use the index and middle finger) and then compare what the measured heart rate is for each beat.

Best,

Ryan

[Richard]

Hi Ryan.
Ah-Ha! Different algorithms. There's the answer.
All good.
Cheers,
Richard.