[nabla9]

I have not tried myself, but maybe Polar H10 strap or older H7. I didn't realize that H10 works with free app, so I bought expensive HRM too. :( The strap has internal memory that can train one session of data.

https://nob.ro/post/polar_h10_ubuntu/

https://github.com/rsc-dev/loophole

https://reprage.com/post/how-to-connect-the-raspberry-pi-to-...

Polar H10 is very accurate. I personally pair it with free PolarBeat app (I also have the Polar HRM) and download raw data.

---

https://support.polar.com/e_manuals/Team_Pro/Polar_Team_Pro_...

>The export raw data function exports second-by-second data from a training session. Raw data export gives you a zip file with player specific folders which contain a CSV file, and a .txt file and a GPX file.

> The CSV file contains second by second information about heart rate, speed, distance, acceleration/deceleration and running cadence.

>The .txt file contains unfiltered RR interval data that can be analyzed with third party heart rate variability tools.

>The GPX file contains location information that can viewed in third party tools.

[founderling]

That looks good! Will buy one next time I am in an electronics store.

I find it surprising that a we still need a chest belt to measure heart beats. I can put a finger on my wrist and feel every beat perfectly. Strange that a wrist band cannot do the same.

[nabla9]

You don't need chest belt. I can go running without the strap and use only the HRM from wrist (it's optical).

The chest band is still more accurate (and cheaper). It gets the minor variations in HR from beat to beat. When you get closer to your maximum HR your hard beat gets more even. HR variability gives more info.

[founderling]

Now I am confused. You can use the "Polar H10" on your wrist? The product description seems to only mention strapping it to your chest.

[nabla9]

Heh, no. I have Polar M430 and H10.

M430 in my wrist. It has it's own optical HR sensor. It does not need H10 to measure HR. Polar H10 is the chest strap, it used electrodes with skin contact to measure HR.

When H10 is available and paired to M430, M430 uses H10 to get more accurate HR measurement data from the strap.

H10 works also alone with a free Polar app so you don't need the wrist monitor, although M430 has GSP and screen so it can measure also distance.

[rahimnathwani]

"I can put a finger on my wrist and feel every beat perfectly

Right, but probably only when you're stationary. Try taking your own probably when you're walking or typing.

[founderling]

In fact, I only want to use it at home while sitting in front of the computer. I want to make some biofeedback experiments to figure out if I can influence my heart rate via meditation.

[wnkrshm]

Maybe this [0] could be of interest to you as well then.

[0] https://github.com/giladoved/webcam-heart-rate-monitor