Ambient pressure in widgets?

Dan.Boilermaker said:

gaijin is correct.  Embedded pressure sensors include temperature compensation on-chip.  Many of those chips will provide a means for the user (in this case Garmin) to have access to the internal temperature reading and is what you as the wearer sees in the Temp Widget.  "Ambient" from the pressure sensor's perspective is the on-chip temperature at the point of the pressure measurement not the more general ambient air temperature external to the watch.

Exactly.  Thank you.

Dan.Boilermaker said:

gaijin is correct.

I'm assuming that you are referring exclusively to the particular issue of the pressure sensor used on the Instinct being or not being temperature compensated. That issue may indeed deserve a discussion, but if you want to do it, you should create a new thread. It is an issue that has nothing to do with the one being discussed in this thread (local pressure vs sea-level pressure) and, as such, its discussion here can only add more noise and confusion, something that we should avoid. There is enough of that here already. Having said that, your post made me feel that a last reply from me was necessary here.

Dan.Boilermaker said:

Embedded pressure sensors include temperature compensation on-chip.

Some do (nowadays most, I would agree), and some do not. As an electrical engineer with many years of circuit design, I have used both kinds. You have probably used both kinds, too (depending on your age and years of circuit design, I guess).

But what matters here is the specific one being used by Garmin on the Instinct, and the fact that Garmin explicitly says that there is no temperature compensation (see the above link that I sent to gaijin). That should settle the debate, independently of what "most" or "many" other chips in other gadgets do, right?

Of course, the manufacturer may be wrong in its statement (often these texts are flawed and misleading). Therefore, if you know for a fact that Garmin's statement is wrong because the pressure sensor that they use on Instinct is temperature compensated even though they say that it is not, then please:

a) tell us how you know that with such certainty that makes you decry the manufacturer's statement (maybe with an electrical circuit schematic, the specs of the chip used on Instinct and its parametrization, or some other hard fact, such as having been an element of the Instinct design team with perfect knowledge of what is inside it, etc). That would be most useful, and I, for one, would be very thankful.

b) be kind enough to warn Garmin, so that they may correct their wrong statement.

But please, do it only if you have the mentioned hard facts on the specific circuitry implemented on the Instinct. General notions about "most" or "many" such chips, or simple opinions (educated guesses as they may be) are, at this point, simply a waste of time and energy, as you very well understand.

Dan.Boilermaker said:

"Ambient" from the pressure sensor's perspective is the on-chip temperature at the point of the pressure measurement not the more general ambient air temperature external to the watch.

Of course. Which is precisely one of the reasons (but not the only one) why sea-level-reduction formulas such as the one discussed in this thread (which need air column temperatures external to the watch), if used on the Instinct, will introduce further errors (unless the watch is taken off wrist and stabilized at equilibrium with the external environment), as I stated above repeatedly.

NOTE: In contrast with the issue of knowing if the pressure measurement is or is not temperature compensated, this aspect has indeed a direct bearing to the topic of the thread.

Best regards 

Which is why I started my post with "Not 100% sure I want to get into this discussion but what the heck".  Should have stuck with my first instinct!!  Going back to first principals, the OP asked if there was a more convenient way to see absolute pressure - try the "Ambient Pressure" widget (one example.)

And why I started my reply to you saying "I fully understand your position. I'm also not sure if there is any point in posting my five cents"