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Comment by brandonb | Hacker News Reader

I suspect they also need oxygen saturation (introduced in the Apple Watch Series 6 in 2020) in order to make their overall sleep apnea detection algorithm work. Given that it only works with the Series 9 or above, it's possible they're also using the the temperature sensor as another input into their algorithm.

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They explicitly only mentioned accelerometer. If they used more sensors, in particular temperature sensor, it's hard to imagine they wouldn't mention in, especially that it would justify them limiting the feature to Series 9 and 10.

However, reading on PAT (Peripheral arterial tone) and existing FDA-approved devices using that, they indeed use oxygen but not temperature. See for example "WatchPAT ONE" device.

Perhaps they aren’t worried about justification

Did Apple resolve the patent issue that disabled oxygen saturation in the Series 9?

Although it's possible that Sleep Apnea detection uses the oxygen saturation sensor but doesn't show its results directly.

It wouldn't surprise me if they did the latter. The oxygen saturation sensor is fundamentally just another optical sensor with a different wavelength of light -- so if you feed all three wavelengths, plus the accelerometer, into a neural network, you may be able to pick up on oxygen-related physiological signals without explicitly processing an oxygen timeseries.

No. I was very curious to see if it might be a last minute thing where it came back but the pages for the series 10 clearly don’t list it and if you use the comparison tool it’s highlighted as gone.

I hope it’s just still disabled. It would suck for someone to buy a new watch, the fix the dispute in 2 months, and you never get the feature until you buy another new watch.

They’re clearly not bending. I don’t know if they’ve given up or waiting on an appeal or maybe home a new administration will tell the ITC to go away or what.

Non-US watch series 10 specification pages mention it still, so it's there and just disabled. I wonder though if they could legally enable it after the fact on watches imported while the ban was in effect

They're still appealing, but the underlying patent expires in 2028, so maybe they'll wait it out.

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