Sensor hardware difference from Series 0 to Series 3 Apple Watch?

[timidhermit]

I like to know if there are ACTUAL hardware differences in the heart rate / activity sensors mounted on the underside of the Apple Watch from Series 0 to Series 3? In particular, did Apple use a different manufacturer, model, type of sensors?

For odd reasons, I can't seem to find an article on this particular topic. For example, is the heart rate sensor accuracy the same between Series 0 and Series 3 if the sensor hardware is identical?

 

[chrisu91]

I think they switched something (or it could just be software). I’ve noticed inaccuracies with my Series 3 but not first generation. I’ll open the heart rate app and it’ll say something like 59bpm 1 minute ago, and then it’ll refresh and jump up to a more accurate 75bpm. This is all at rest so there shouldn’t be that large of a discrepancy.

Same thing sometimes happens when polling my heart rate. It will initially display either a high or low HR, and rapidly jump around to different numbers. I have a 12 second video showing my watch reading my HR at 99bpm, 4 seconds later dropping to 86, and then down to 81.

 

[Otflyer]

I think they switched something (or it could just be software). I’ve noticed inaccuracies with my Series 3 but not first generation. I’ll open the heart rate app and it’ll say something like 59bpm 1 minute ago, and then it’ll refresh and jump up to a more accurate 75bpm. This is all at rest so there shouldn’t be that large of a discrepancy.

Same thing sometimes happens when polling my heart rate. It will initially display either a high or low HR, and rapidly jump around to different numbers. I have a 12 second video showing my watch reading my HR at 99bpm, 4 seconds later dropping to 86, and then down to 81.

I think all watch models are the same. My SS series 3 does what yours does.