Support for O2 Flex (update: model PO6)

[bohdan-s]

Any plans to support the O2 Flex (https://shop.sleephq.com/products/home-sleep-test-with-device) ?
Seems to be 1/2 the price of the rings.

[ilyakruchinin]

Someone would have to buy it or find an equivalent Viatom model to confirm.

[ilyakruchinin]

The SleepHQ O2 Flex is based on the Viatom / Wellue O2Ring Air (also known in OEM listings as the PO6 series).

It is designed as a lighter, budget-friendly alternative to the flagship Wellue O2Ring (PO2 series). Key hardware distinctions from the standard O2Ring include:

Form Factor: A lighter, thinner silicone loop design compared to the bulkier body of the original O2Ring.

Display & Vibration: It strips back or simplifies the onboard OLED feedback mechanism and haptics to cut manufacturing costs and reduce weight.

Firmware/Protocol: Like the standard Wellue devices, it uses Viatom's core BLE protocol for continuous pulse oximetry, allowing it to sync directly with both Viatom/Wellue companion apps and the SleepHQ mobile/desktop ingest tools.

[ilyakruchinin]

Likely already supported (DISCLAIMER: NO GUARANTEES - WE NEED A REAL USER/OWNER TO CONFIRM)

[ilyakruchinin]

The SleepHQ O2 Flex uses the older Gen 1 Viatom BLE protocol, not the newer Gen 2 protocol.
Technical Breakdown
Gen 1 Protocol (O2 Flex / Wellue O2Ring classic):
Sampling & Storage Interval: Writes historical record entries at a 4-second resolution.
BLE Communication: Uses Viatom's legacy command/response framing over custom Nordic-style UART characteristics (0xAA header packets with sequential block downloads). Real-time telemetry broadcasts live packet bursts containing current SpO2, PR, and motion flags.
Ecosystem Support: Fully compatible with open-source parsers, SleepHQ's standard sync routines, and legacy desktop software (O2 Insight Pro).

[ilyakruchinin]

Unless SleepHQ have customised firmware IDs (again, unlikely) I'd say it is highly likely already supported.
If not - should be easy to add support.
See above disclaimer.

[bohdan-s]

Amazing!
Off topic, but does the Gen 2 provide anything extra other than the 1s sampling?
Finding it hard to justify the nearly double price of the Ring S (Gen2) over the Ring (Gen1)

[ilyakruchinin]

SleepHQ O2 Flex (Budget Ring) vs. O2Ring S (Gen 2)

Beyond the difference in data recording resolution (4-second sampling on the budget model vs. 1-second sampling on Gen 2), there are several key hardware, firmware, and architectural distinctions between the two devices.

---

Comparison Matrix

Feature	SleepHQ O2 Flex / Budget Model	O2Ring S (Gen 2 / Pro)
Charging Interface	Proprietary magnetic dock / pogo-pin cable	Native USB-C port
Continuous Battery Life	~12–16 hours per charge	Up to 24 hours continuous monitoring
Data Recording Interval	4-second resolution	1-second resolution
Optical Front-End & DSP	Standard DC baseline filtering; basic motion logic	200 Hz raw sampling chip with updated frequency-domain noise filtering
Motion Artifact Handling	Higher sensitivity to false desaturation dips during finger movement	Improved dynamic filtering to discard motion noise during bed turns
Onboard Display	Stripped back / minimal LED indicator to reduce cost & power draw	Integrated OLED screen displaying live SpO2, PR, and battery levels
Vibration & Haptics	Fixed-intensity or simplified alert motor	Fully customizable threshold alerts (SpO2 drop thresholds, low/high PR)
Onboard Storage	~1–2 overnight sessions	4 sessions × 10 hours (~36,000 data points per session)
Enclosure & Form Factor	Thinner, lightweight silicone loop	Contoured ergonomic chassis with reinforced finger ring clasp
BLE Protocol	Legacy Gen 1 framing (0xAA header, standard UART services)	Gen 2 binary block protocol (optimized for high-density 1s data sets)

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Key Hardware & Practical Differences

• Native USB-C Charging:
  The O2Ring S integrates a native USB-C charging interface directly on the body, doing away with the proprietary magnetic cables or docks that can be easily lost or misaligned.

• Battery Endurance & Power Management:
  The Gen 2 architecture extends continuous runtime up to 24 hours, providing ample headroom for back-to-back night tracking or naps without requiring an immediate daytime recharge.

• DSP & 200 Hz Optical Processing:
  The Gen 2 optical sensor samples raw PPG signals at 200 Hz before filtering, allowing the internal DSP to isolate genuine vascular desaturations from motion artifacts and perfusion drops caused by hand shifts during sleep.

• Onboard UI & Custom Haptics:
  While the O2 Flex simplifies the interface to keep weight and cost down, the O2Ring S features a built-in OLED display for real-time readings and programmable haptic vibration alarms that can wake the wearer when SpO2 drops below a configurable threshold.

[ilyakruchinin]

Of the above, I'd say 1s data sampling is the only significant difference

[bohdan-s]

Thank you :) I now realise I could of used ChatGPT myself ;)
Just want to say Thank you! I’ve been using SomnuTrace for a week so far and it’s exceeded expectations!

[zzzdrkarlzzz]

Just found one on ebay, item 186186521371, Wellue Oxyfit Bluetooth Finger Pulse Oximeter Heart Rate Monitor TGA Certified for $50.
I'll get it next week and report back if somnotrace can pair with it.

[zzzdrkarlzzz]

Received the Wellue Oxyfit.
Somnotrace detected it straight away and pair without issue as a gen 1 device

Data captured without issue

For some reason i took it off last night around the 4hr mark so can not confirm data collection past the 4hrs. Will test again tonight.
For $50 seems like a good option

[ilyakruchinin]

@zzzdrkarlzzz - any updates on the 4-hour limit?
Please let us know.

[zzzdrkarlzzz]

Sorry for the delay, been away.
A few quirks.
6.5 hr session that only uploaded the last 4 hrs
The ring does not reconnect itself and therefore doesn't "stream" the data (if it is meant to?) so it appears the 4 hr limit is real if that behavior can't be fixed. seem like the ble connection goes stale?
To get last nights data into Somnotrace, I had to un-pair then re-pair again. It re-paired without hassle and then automatically downloads the 4 files.
I've attached a log it it helps. Let me know if i can provide any further info to help as for the cost this could be a good device to help add the extra o2 data
Somnotrace.log
I will upload a screenshot of the nights traces when i get back home

[ilyakruchinin]

Thank you. I've created a new issue for this (honestly, I don't think it should require re-pairing).
#288
The 4 hour limit is real AFAIK (cannot be fixed). But MAYBE we can go to capture live streaming instead (instead of pulling files AFTER the fact). Low priority (sorry), but on the roadmap.

I'll first check the logs (a bit later) and see if there is anything obvious about the re-pairing issue (which shouldn't be needed).

[zzzdrkarlzzz]

Whenever you can get to it, much appreciated. Let me know if you need any further data from my end.
Thanks for all the effort you have put into ST

[beren12]

check out https://www.reddit.com/r/SleepApnea/comments/1t325mz/i_just_finished_testing_over_20_overnight_pulse/ and https://optimizeyourbiology.com/continuous-oximeter-database emay sleep o2 is the best overall in testing, and is on ebay for like $30 right now. I just ordered one.

[ilyakruchinin]

Not supported by ST.
Has a different protocol. Its author has deleted the GitHub repo with specs (although pip modules still available).
Unless we know the reason for the repository removal, I wouldn't count on it being supported.

[beren12]

yeah what poor timing...