[tamadevr]

We are hoping to provide software-only packages as well however at the moment, most wearables actually don't provide the realtime peak-to-peak heart rate interval data required to do the type of closed loop biofeedback we do. Once wearables are able to support this type of data we would love to provide Flowly software-only.

[disabled]

To do accurate and reliable HRV analysis you need a sensor (PPG/ECG/etc) that has a sampling rate of 500-1000 Hz minimum. This is especially the case for closed-loop. This is in order to do further calculations such as via respiratory sinus arrhythmia, to detect respiration rate.

“More conservative guidelines advise between 500 and 1000 Hz (Riniolo and Porges, 1997; Berntson et al., 2007), which may be particularly relevant in case of lower amplitude RSA (Riniolo and Porges, 1997).”

See: https://www.frontiersin.org/articles/10.3389/fpsyg.2017.0021...

In terms of notable hardware you may want to look at this:

https://plux.info/kits/511-bitalino-mini-solo-kit-810121033....

Anyways, this series of boards (biosignalsplux) interfaces with Android/iOS/Unity/etc via hardware-specific SDKs.

Obviously Unity is for SteamVR or just Steam in general.

The boards also have official support for the package LabStreamingLayer (there are also LSL interfaces for Unity on GitHub), which is extremely useful for the kind of work you are doing, with respect to calculations, processing, and analysis.

I actually routinely work with physiological signals generated from the autonomic nervous system, and I do both processing and interfacing sides of this work. I also have an immune-mediated form of ANS failure, so I have personal relevant and translatable experience with respect to your project as a patient too.

I hope this info helps!

[tamadevr]

Thank you for summarizing this so clearly and explaining why most wearables don't provide the data we need to do biofeedback training. Appreciate your insight here.