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yepp

macrumors member
Original poster
Oct 20, 2018
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I heard “updated sensors” for series 9 and ultra2. Do we know if this is true and if yes, which sensors are updated?
 
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That was the rumour but I don't recall Apple mentioning that and the website doesn't mention it either.
 
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I’m curious too. Especially if the heart sensor is any better than the series 4 I currently own.
 
I’m curious too. Especially if the heart sensor is any better than the series 4 I currently own.

Per https://www.apple.com/watch/compare/ everything since the AW6 is one generation past the AW4 for the heart sensor.

AW4:
  • Electrical heart sensor and second-generation optical heart sensor
AW6:
  • Blood oxygen sensor;4electrical heart sensor and third-generation optical heart sensor
AW8:

  • Temperature sensor,7 blood oxygen sensor;4 electrical heart sensor and third-generation optical heart sensor
AW9:
  • Temperature sensor,7 blood oxygen sensor;4 electrical heart sensor and third-generation optical heart sensor
Ultra:

  • Temperature sensor;7 blood oxygen sensor;4 electrical heart sensor and third-generation optical heart sensor; depth gauge; water temperature sensor
Ultra 2:

  • Temperature sensor;7 blood oxygen sensor;4 electrical heart sensor and third-generation optical heart sensor; depth gauge; water temperature sensor
 
Thank you that’s exactly the info I was looking for! Apples chat support was not helpful at all 🤦‍♂️
 
That is immensely useful. Now, we need to find out whether the algorithms used with the sensor may have changed…

Of course, that should be part of the Watch OS, but it could depend on advanced CPU, neural learning engine, etc.

Better algorithms, even with the same sensors, could mean better heart rate, ECG, O2, sleep, temperature monitoring.

Any news on whether Watch OS 10 or the Watch Series 9 brings improvements in those areas?
 
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I could swear that I read that it was improved but now I can not find that same information.
‘Is it improved or not?
 
I suspect that the heart rate and blood oxygen sensors may be taking more frequent measurements on Series 9 and ultra 2. Why?

1) New S9 chip is supposed to be more power efficient although Apple still suggests 18 hrs and 36 hours battery life.
2) I heard that the finger tapping gesture requires oxygen measurement to accurately detect the gesture.
3) Ultra battery life on low power mode has jumped from 48 hours to 72 hours. Now, what does low-power mode disable? - Background measurements from health sensors.

I should emphasize — this is just my speculation. Any thoughts?
 
I suspect that the heart rate and blood oxygen sensors may be taking more frequent measurements on Series 9 and ultra 2. Why?

1) New S9 chip is supposed to be more power efficient although Apple still suggests 18 hrs and 36 hours battery life.
2) I heard that the finger tapping gesture requires oxygen measurement to accurately detect the gesture.
3) Ultra battery life on low power mode has jumped from 48 hours to 72 hours. Now, what does low-power mode disable? - Background measurements from health sensors.

I should emphasize — this is just my speculation. Any thoughts?


I don't think your train of thought it completely unreasonable, there should be optimization with the new processor, but I think that's too big a change to go unannounced.
 
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I suspect that the heart rate and blood oxygen sensors may be taking more frequent measurements on Series 9 and ultra 2. Why?

1) New S9 chip is supposed to be more power efficient although Apple still suggests 18 hrs and 36 hours battery life.
2) I heard that the finger tapping gesture requires oxygen measurement to accurately detect the gesture.
3) Ultra battery life on low power mode has jumped from 48 hours to 72 hours. Now, what does low-power mode disable? - Background measurements from health sensors.

I should emphasize — this is just my speculation. Any thoughts?
I wonder if the newer chip will support more future tech that they didn't announce yet. Could they just turn on other features down the line.
 
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2) I heard that the finger tapping gesture requires oxygen measurement to accurately detect the gesture.
I believe the double tap leverages changes in blood flow, so probably simply using the hr sensor. O2 readings take too long and are a huge battery suck, so probably not used for such a quick motion gesture.


If this is true, then he hr sensor would have to be active almost anytime the screen is “on.” So, presumably, it will be taking more frequent measurements. I don’t think the new watches have new sensor hardware, though. I would think they’d want to explicitly state that if it were so.
 
I believe the double tap leverages changes in blood flow, so probably simply using the hr sensor. O2 readings take too long and are a huge battery suck, so probably not used for such a quick motion gesture.


If this is true, then he hr sensor would have to be active almost anytime the screen is “on.” So, presumably, it will be taking more frequent measurements. I don’t think the new watches have new sensor hardware, though. I would think they’d want to explicitly state that if it were so.

I also think that it’s certainly still the same sensor hardware. You’re right, perhaps the heart rate measurements are measured more frequently (not blood oxygen). Google Pixel watch measures heart rate continuously every second, so it means that it must be feasible without huge battery drain.

Maybe, Series 9 and Ultra 2 similarly measures HR every second for gesture detection, although these measurements are perhaps still not recorded in the health app due to inaccuracy. Possibly, that’s why Apple chose not to mention such more frequent HR measurements in its presentation.

I know, this is too many speculations :)
 
I believe the double tap leverages changes in blood flow, so probably simply using the hr sensor. O2 readings take too long and are a huge battery suck, so probably not used for such a quick motion gesture.


If this is true, then he hr sensor would have to be active almost anytime the screen is “on.” So, presumably, it will be taking more frequent measurements. I don’t think the new watches have new sensor hardware, though. I would think they’d want to explicitly state that if it were so.
Not necessarily. It’s possible that the gesture detection only activates based on a trigger (interrupt) from the accelerometer at the moment of the first tap and the actual pattern then being recognised to identify a double-tap gesture is the subsequent opening of the fingers again followed by a closing of the fingers, presumably both detected by whatever blood flow changes Apple mentioned when discussing the feature, and terminating in another vibration from the fingers contacting each other for the second tap.

I’m not saying this is how it works but it’s at least concievable.
 
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If the sensor has not changed, the double tap thing should work with the original Ultra, too. I know the Ultra 1 has this in accessibility but it does not work on my Ultra.
 
If the sensor has not changed, the double tap thing should work with the original Ultra, too. I know the Ultra 1 has this in accessibility but it does not work on my Ultra.
The sensors may be the same, but Ultra 2 has a more advanced chip. So maybe the U2 is able to process a more complex algorithm to detect the finger taps than the U1.
 
If the sensor has not changed, the double tap thing should work with the original Ultra, too. I know the Ultra 1 has this in accessibility but it does not work on my Ultra.


Unless the double tap requires CPU and Neural Engine input that the S8 and below cannot match.


The accessibility double pinch is not great, but not terrible. I tried those features for a while (still have it turned on) and they're not terrible, but I can see a more contextual and accurate double tap being a victory.
 
The sensors may be the same, but Ultra 2 has a more advanced chip. So maybe the U2 is able to process a more complex algorithm to detect the finger taps than the U1.

It will be interesting to see! I purchased the Ultra 2 for this and to give my brother the Ultra 1 for his birthday, but after finding out the sensors are the same, i cancelled the order. Will have to find something else as a gift!
 
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