
Oura Ring 2 Teardown - zdw
https://www.ifixit.com/Teardown/Oura+Ring+2+Teardown/135207
======
z3ugma
I saw a talk on consumer wearables in sleep at the Sleep Trends conference
this spring. There was a great presentation comparing consumer sleep trackers,
and how their advertised reporting of "accuracy" can be misleading.

If you do a thought experiment: let's say I make a "sleep tracker" that is
just a piece of plastic, no sensor, and write an algorithm that always
presumes the wearer is in stage N2 sleep. Since we spend around 50% of our
night in N2 sleep, this algorithm would start with a fairly high baseline
accuracy of 50%.

Sensitivity and specificity are much better measurements of accuracy, because
they measure the false positive and false negative rates. A comparison of Oura
against a medical polysomnogram showed that while it's very good at detecting
sleep, it's very bad at detecting _not_ sleep:

From
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6095823/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6095823/):
"ŌURA ring had a 96% sensitivity to detect sleep, and agreement of 65%, 51%,
and 61%, in detecting “light sleep” (N1+N2), “deep sleep” (N3),and REM sleep,
respectively. Specificity in detecting wake was 48%"

The current state of the art in sleep measurement really requires some sort of
EEG measurement beyond just PPG and HR, what Oura uses. The Dreem headband is
a good example ([https://dreem.com/](https://dreem.com/)), but it's definitely
more cumbersome than a ring. It's tailored more like a medical service for
insomnia than for the average consumer interested in quantified self.

~~~
marcinzm
>It's tailored more like a medical service for insomnia than for the average
consumer interested in quantified self.

There used to be a EEG headband aimed at the quantified self group (cost $100
or $150) but they went out of business. Probably because for that group a
fitbit like tracker was good enough. So I'm guessing the medical side and
higher price point is seen as a better business model.

~~~
scrollaway
Last time this came up I mentioned the Dreem headband which is still actively
produced.

~~~
marcinzm
The post I replied to mentioned Dreem but they're at a $500 price point from
what I can tell which is beyond the usual non-medical need consumer.

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dirtyaura
A long-time HN user here and I’m stoked to see our product on the HN front
page

Note: If you are interested in working at Oura, we are hiring SW Engineers
both in Helsinki, Finland and San Francisco.

Current open positions can be found on
[https://ouraring.com/careers](https://ouraring.com/careers) and new positions
are opening in a few weeks.

~~~
robterrell
Congrats on getting your product ripped apart on video ;)

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amacbride
Ultra-low power indeed: I often get 6+ days of use before having to recharge.
I’ve been very happy with mine; the sleep tracking seems quite consistent with
my subjective experience, and the activity/exercise detection matches closely
with the data from my Apple Watch.

~~~
gregwebs
I love the aura ring. AFAIK it is clearly the best non-intrusive sleep tracker
and I would recommend it to anyone for _sleep_ tracking. But in my experience
the activity tracking is horrible because the ring achieves low power
consumption by being off most of the time. I would suggest using a different
device for daytime activity tracking.

~~~
gambiting
Serious question - what is sleep tracking useful for? While I can see the
benefit of tracing activity, I have no idea why would I want to track my
sleep. I fall asleep, I wake up, what is there to track? Or rather, even if it
tells me that I had a period of less/more movement during the night, what kind
of actionable information can you possibly get out of it?

~~~
sprucely
It allowed me to identify food intolerances that had a significant impact on
my sleep.

~~~
Tronno
I am struggling with a similar problem (food, and gas in particular, affecting
my sleep) and was wondering if you'd be willing to share more about your
experience.

~~~
sprucely
Sorry for such a late reply. For me the two biggest culprits are sulfites
(increased sleep disturbances) and fructose (reduced deep sleep and more
chaotic cycles).

What's weird about the fructose is I don't have the symptoms associated with
such an intolerance; namely gas. Good news is that there is an enzyme
(Fructaid) that helps mitigate it for me, so I don't have to completely cut it
from my diet.

In the US, sulfites can be sneaky. Labels are required to list them if
directly added to a product, but not for sulfite-containing ingredients
sourced from a third-party. So the raisins in that trail mix very likely
contain sulfites.

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Jhsto
Also worth noting that the ring itself is not designed by Oura but by another
company: [https://haltian.com/reference/oura-
ring/](https://haltian.com/reference/oura-ring/)

Further, even though Oura is a private company, its financial information is
public (as is any Finnish company's):
[https://www.finder.fi/Tuotekehitys+tutkimus-+ja+suunnittelup...](https://www.finder.fi/Tuotekehitys+tutkimus-+ja+suunnittelupalvelut/Oura+Health+Oy/Oulu/yhteystiedot/2792854)

~~~
dirtyaura
This is incorrect, the Oura ring 2 has been mostly designed by in-house team,
not Haltian. They have been involved in the process though.

~~~
Jhsto
Thanks for the correction! I don't know the details on the second iteration
(assumed same applies as with the first gen), so I assume you have better
information.

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Erlich_Bachman
Before buying one I tried to make research about its effectiveness and there
are some very alarming reports, coming, of all places, from the research
published by the same company. So this isn't even biased...

    
    
        “From EBE analysis, ŌURA ring had a 96% sensitivity to detect sleep, and agreement of 65%, 51%, and 61%, in detecting “light sleep” (N1), “deep sleep” (N2 + N3), and REM sleep, respectively. Specificity in detecting wake was 48%.”
    
        Specificity in detecting wake was 48%! If this was a medical test, it would never be approved by FDA.
    
        A specificity of 48% means that there is a 48% chance that someone is awake when the device says they are asleep.
    
        That is horrible.
    

This is very surprising and alarming. As the author later goes on to describe,
this has real implications and possible negative effects, this is not just a
benign error here and there. Users are apparently supposed to use the Oura
data to change or at least adjust and improve their sleep habits, and of
course if they will do it based on faulty information, the adjustments
themselves are going to be faulty and it can lead to worse or sub-optimal
sleep!

Apparently you can still use Oura to track heart rate and HRV, but their own
proprietary markers like “readiness” are probably based on all of their data
including sleep, so they are not going be that accurate either.

~~~
wvl
This matches my experience having received one Nov 2018 (and returning it a
few weeks later). It was constantly getting my actual sleep times wrong, more
often than not marking me as being asleep while watching tv in the evening.

After contacting support, their solution was an upcoming update to their app
where I'd be able to edit the data so that I could override the app whenever I
knew it was wrong. Which completely invalidates the primary reason to own this
product. I mean, if I knew when I was asleep, why would I need a ring to track
it?!

So given that it couldn't properly track sleep, doesn't track activity (by
design), the only other purpose in my mind was to track HRV. And count me as
skeptical of the accuracy of that data as well.

------
BiteCode_dev
Just did the Tour du Mont Blanc (8 days of mountain hiking) with the oura 2 in
plane mode. It recorded everything.

I misplaced it in the washing machine twice and it still works as brand new.

Besides the proprietary aspect of the platform and false positive reporting
sleeping while not, I have only good things to say about mine.

Nifty little device.

------
gregwebs
If you have an oaura ring you can participate in a USCF study that is trying
to determine if it can help predict COVID: [https://ouraring.com/ucsf-
tempredict-study](https://ouraring.com/ucsf-tempredict-study)

I think the idea is similar to what the NBA is doing: monitor doctors and
nurses with the ring to try to detect COVID. But they are trying to properly
study the idea.

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krustyburger
I am impressed with my ring after having had it for about a year. The battery
life seems to be as good as ever. The only concern I have is that I often have
to wear it on a different finger. My hands are less bloated, which I credit
partly to having been more active since I’ve had it.

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wazHFsRy
From my experience the last thing you need for good sleep is a tracker. I’d
try to fix sleep hygiene first and adapt a strict sleep schedule you do every
day.

~~~
scrollaway
Some people (myself included) fix (sleep) hygiene problems by first closely
watching and diagnosing them.

Your comment would sound silly if it said "last thing you need for good code
is a debugger, I'd try to add a linter first". Or "last thing you need to
maintain a good weight is a scale, I'd try to eat better first".

Neither are exclusive, and the former helps the latter if you use it well.

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underyx
> The Oura Ring came out in May 2019

Wait, what? I got mine in Feb 2019. Did they re-release it or something?

~~~
dirtyaura
Oura ring 2 launched in Dec 2017 and shipments started in April 2018.

~~~
voisin
That’s a long time since new launch. Have they refined it since 2018?

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unicornporn
Didn't know what this ring was. Is it better than binary sleep/wake tracking?
Here's the closest thing to a study on this thing I found:
[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6095823/](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6095823/)
:-/

~~~
dirtyaura
There are a few others, some of them by in-house science team

[https://iopscience.iop.org/article/10.1088/1361-6579/ab840a](https://iopscience.iop.org/article/10.1088/1361-6579/ab840a)

[https://www.researchgate.net/publication/335764849_Following...](https://www.researchgate.net/publication/335764849_Following_the_heart_what_does_variation_of_resting_heart_rate_tell_about_us_as_individuals_and_as_a_population)

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sadfasdfsad
It's a great device.

If there is a primary flaw, it's that it can't be resized. If you are
sufficiently motivated to become more active, the ring becomes too loose over
time.

Not the worst problem, but it ends up in caught in the drain more than I'd
like.

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oneplane
I wonder if it's currently technically feasible to make a version with
swappable batteries while maintaining the same form factor, functionality and
other properties the product has as-is.

I know a lot of other products could have better serviceability and
repairability if one were to sacrifice form factor, dimensions or aesthetics,
but for a product like this it doesn't seem obvious to me how one would go
about that, but it'd be very interesting to speculate on.

~~~
theshrike79
Not really no, the whole package is encased in a completely waterproof way.

Any kind of swappability would require connections, which in turn would
compromise the IP rating.

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cinntaile
What's the reason that you can't use this ring for exercise? It feels like
such an obvious feature to include so there must be some technical reason?

~~~
hobofan
I would assume that to achieve a 7 day battery life they only take rare
measurements of your heart rate, which makes it unfit for the kind of high
resolution heart rate tracking people are used to from fitness watches. They
also mention that any sport which has a significant level of hand involvement
might disturb the reading.

They do still track general intensity of activity though, which for general
health is probably a more relevant metric than exact heart rate.

~~~
dirtyaura
Night-time PPG measurement of Oura ring IS high-resolution. PPG is measured
only when you are still enough.

Activity tracking is based on accelerometer data.

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xnzakg
Anyone else prefer the text + pictures teardown format over the video
teardowns they've been doing recently?

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nwah1
Would it be possible to have this device charged kinetically, or via body
heat, or ambient wifi?

