Elisha
macrumors 6502a
I know how it is used. It's still next to useless on a phone as opposed to an actual device dedicated to tracking your activity.
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iPhone SE and the missing barometer
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I know how it is used. It's still next to useless on a phone as opposed to an actual device dedicated to tracking your activity.
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If you're not interested in discussing the barometer, why are you commenting in a thread dedicated to the discussion of the barometer?
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gim
macrumors 6502
Well, I thought the M9 could be able to distinguish between climbing stairs and doing normal steps, therefore it seems quite possible.
Why are you being so reactionary? I started the thread to discuss the barometer. I'd be surprised if it has no benefit at all? I'm genuinely curious, do you have any evidence or links that might explain its uselessness?
hank moody
macrumors 6502a
zhenya
macrumors 604
I would bet that the iPhone is the single most used gps activity tracking device in the world by a significant margin.
Elisha
macrumors 6502a
Elisha
macrumors 6502a
Do you have any evidence that now that it's been taken off, your fitness tracking is going to be significantly impacted.
Anyone actually worried about it would get a proper fitness tracking wearable and not a phone that is not always on you 100% of the day.
Mr. Buzzcut
macrumors 65816
Yep, whenever I go to the doctor they record barometric pressure on my chart.
I don't recall too much fanfare when it was added. Maybe I missed something. How are y'all using it now? Honestly, for health, I think temperature would be much more useful to combine with heart rate and activity levels.
oneMadRssn
macrumors 603
I am 99% sure the barometer was not used for anything. Indeed, other than a weather enthusiast app, I don't see any use for it. Then again, it's not like the iPhone has a wind-speed sensor either...
- Counting steps on stairs and floors is done using the accelerometer. By integrating or taking the derivative of the acceleration vectors over time, one can calculate position and speed.
- Elevation on the ground is built-in to the GPS data. Indeed without it GPS would not work at all. Also, take a look at the raw GPS data output by your iPhone 6 or 6S if you ever get a chance. It is quite inaccurate; fluctuates 10-20 feet in all directions all the time. It only becomes accurate if lots of measurements are averaged, your directional vector is calculated, and this is analyzed in the context of a map where your position can be snapped to a known street or trail. You need a much larger antenna and very good signal to as many satellites as possible to get a better measurement.
- Barometric pressure is a very bad way to measure small changes in elevation (such as inside buildings). For example, going from sea-level to 25ft above sealevel results in a change of .08inHg, or approx 1millibar, which is less than natural fluctuations in pressure, which can be as much as 10millibars or .3inNg per hour. Meaning, the pressure change from climbing some stairs is pretty much indistinguishable to the sensor from the changes that just occur when you stand in one place, indeed, it's probably just noise to the sensor.
- The barometer is not helpful to your running / hiking / trail running / biking / skiing / whatever apps.
- Counting steps on stairs and floors is done using the accelerometer. By integrating or taking the derivative of the acceleration vectors over time, one can calculate position and speed.
- Elevation on the ground is built-in to the GPS data. Indeed without it GPS would not work at all. Also, take a look at the raw GPS data output by your iPhone 6 or 6S if you ever get a chance. It is quite inaccurate; fluctuates 10-20 feet in all directions all the time. It only becomes accurate if lots of measurements are averaged, your directional vector is calculated, and this is analyzed in the context of a map where your position can be snapped to a known street or trail. You need a much larger antenna and very good signal to as many satellites as possible to get a better measurement.
- Barometric pressure is a very bad way to measure small changes in elevation (such as inside buildings). For example, going from sea-level to 25ft above sealevel results in a change of .08inHg, or approx 1millibar, which is less than natural fluctuations in pressure, which can be as much as 10millibars or .3inNg per hour. Meaning, the pressure change from climbing some stairs is pretty much indistinguishable to the sensor from the changes that just occur when you stand in one place, indeed, it's probably just noise to the sensor.
- The barometer is not helpful to your running / hiking / trail running / biking / skiing / whatever apps.
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zhenya
macrumors 604
I'm talking about people who use specific apps for tracking running/hiking/biking/etc. Again, I'm pretty sure the iPhone is the single most commonly used device for such things.
And yet there are apps that leverage its data, including, as I noted, the running app I use. If a barometer is a useless tool for tracking elevation, then why is it still included in virtually every high end gps watch?
oneMadRssn
macrumors 603
I don't purport to know every running app. I do know some physics, math, and how to read a spec sheet. It just doesn't make sense in a location/elevation sort of use.
Do you know what specifically the app you're refering to uses it for? Does the developer explain in what way this barometric pressure data is implemented?
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I did more reading on this. Altitude can be estimated using barometric pressure, but only to about a 100meter accuracy. So this is petentially useful in, for example, an unpressurized cabin airplane or helicopter for novelty, maybe for climbing a mountain, but certainly not useful for indoor floor by floor elevation.
So maybe if people trail run and have ascents and descents of 600+ft, the barometer might have some input then. Otherwise, I am not sure that sensor makes any useful input what so ever.
Elisha
macrumors 6502a
I get that people dislike losing something they had before even if they never used it. But in this case as it has already been pointed out by @oneMadRssn it was useless to begin with.
Folks, all weather apps have barometric pressure including the built in weather apps. There's no need for a barometric sensor in a phone, it just happens to be in the some of the modems Apple purchases. You could say apple dropped the ball by not including an IR blaster, wireless charging, dog whistle, altimeter, trundle wheel, DNA sensor, breathalyzer, etc.... But do we really need every sensor in the world?
I7guy
macrumors Westmere
I use a barometer app to track the atmospheric pressure and the readings over time are indicative of when I will get a sinus attack. So not useless.
Thank you for your contribution. But isn't it time you remind yourself that you're not interested in the barometer?
[doublepost=1458807753][/doublepost]Some folk are kinda weird on here.
Anyway, as I stated from the start. It's not a huge deal for me. I would have liked it for it's added tracking accuracy, but the phone still looks good for my needs.
See you later and thanks for all the opinions.
zhenya
macrumors 604
10 meter accuracy seems to be the more accepted number for a moderately calibrated unit, and with a barometer paired with a phone knowing local weather data and gps, calibrating it automatically and constantly should be fairly trivial, making it much more accurate still. I do runs with climbs of greater than 1000' elevation gain several days or more per week, fwiw.
Implemented correctly, the best solution is to have a unit that contains both systems, continuously calibrated, and used in conjunction.
Elisha
macrumors 6502a
I7guy
macrumors Westmere
Pressure changes don't relate linearly to altitude. This chart may help some of you. http://www.aeco.com/download/altitude.pdf
The resolution of the barometer (in coarse terms) is important. I have no idea what the 6s sensor's resolution is. In aviation meteorology we use .01" of mercury as our reporting steps.
The resolution of the barometer (in coarse terms) is important. I have no idea what the 6s sensor's resolution is. In aviation meteorology we use .01" of mercury as our reporting steps.
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