Calibration on iPhone 5s Compass and Level Appears Incorrect

[benfranke]

What people don't seem to realize is that this affects any app using Gyroscope data. I don't use my iPhone to level my cupboards and I sure wouldn't use the compass to find my way out of the woods when I'm lost.

However I sometimes take a panorama shot which now is even harder because I have to follow a -3° horizontal path.
The maps app shows me facing a slightly different direction, which might cause issues with routing apps that do not solely rely on GPS data but improve their navigation with sensor data, such as Wi-Fi/Cellular location and the gyroscope.
Game apps that rely on the gyroscope are obviously screwed right now, unless they allow you to recalibrate an offset value.

I really love my iPhone, but I'm not paying 700 bucks for something that is even remotely broken.

 

[ScubaCinci]

A spirit level is only accurate on it's given length. If you compare one like on the iPhone that is 2 inches in length against one who is 6 inches in length, they will not give the same readings. A 6 inches lenght compass against a 3 feet long one will also give different readings. The longer the better...yes size matters when it comes to compass accuracy.

So before you all laugh at it we should think of where would it be accurate to use such a spirit level. That's all...only my two penny's worth.

As a carpenter it makes me chuckle the gripe that some of you seems to have about it.

This ^ - I'm glad I'm not the only one.
Anyone who uses their phone as a level for actual carpentry work should be pointed to and laughed it with derision.

News flash...the GPS may be off a few meters too

 

[ValSalva]

This ^ - I'm glad I'm not the only one.
Anyone who uses their phone as a level for actual carpentry work should be pointed to and laughed it with derision.

News flash...the GPS may be off a few meters too

No wonder the framing to the addition to my house looks crooked

 

[ViperDesign]

he looks to be holding it wrong

 

[Jets fan]

 

[mono1980]

What App are they using for the level?

The built-in compass app, that now has a level function. It's pretty sweet.

 

[Old Muley]

The problem is they are using a Stanley level. Cheap, plastic and disposable...

 

[putongnihongo]

1 degree off here, I know it's petty but if I spend lots of $$$ on a device I want it to function as promised!

 

[Jets fan]

 

[Megakazbek]

I don't understand people who think it's not a big deal. It's basically a component that cannot serve its intended purpose: you can't measure levels or directions with it, you cannot properly control games or apps like Star Walk, etc. And those kind of apps are not tolerant to errors but on the opposite they are enabled exactly by high precision of sensor - even with 1 or 2 degree bias it's already useless as a level or as a gaming controller.

It's as if the mute switch didn't function on your phone: not a big deal because you can always mute from OS, but it would be still a part of your device that's there by design and yet doesn't work.

 

[Jets fan]

The problem is they are using a Stanley level. Cheap, plastic and disposable...

The Stanley level is a junk level but its accurate in a pinch!! I hope you fall off your high horse!!!!

 

[lostngone]

The internal compass/level/gyro is flawed.

Do you use any games that require you to tilt the phone? Driving games, star gazing apps, panoramic pictures that require you to move your phone level horizontally. The phone does not know what level is! Your car will always pull to the right or left in racing games unless you unnaturally tilt the phone. The stars will not match up with the horizon in star gazin apps.. Its a MAJOR issue.

It is not flawed

For it to be accurate an accelerometer has to be calibrated. When it is powered up an accelerometer has no idea what position it is in. Using other sensors in the device it can make a rough calculation but it is better to always manually calibrate.

 

[scottwaugh]

seems like all kinds of issues with iOS 7.. glad i am still on iOS 6 until a jailbreak comes out

This isn't an issue with iOS 7 - its an issue with the iPhone 5s and 5c which exhibit the issues quite often - wouldn't matter what iOS they were running. The 5 and 4s don't show the issues in iOS 7.

Definitely something Apple needs to fix as these hardware services are used by all kinds of applications, games to other more serious uses - hopefully an update will get it taken care of.

I don't understand people who think it's not a big deal. It's basically a component that cannot serve its intended purpose....It's as if the mute switch didn't function on your phone: not a big deal because you can always mute from OS, but it would be still a part of your device that's there by design and yet doesn't work.

I agree, a bit like watching the Samsung faithful defend Samsung's attempt to rig benchmarking results for their phones. It's something that works on earlier iPhones no matter the iOS version - it exhibits a rather consistent error (some are more or less, but most are the same amount) so it seems to be obviously a engineering error somewhere (software or hardware) slipped through. Apple just needs to fix it - and I'm sure they will.

 

[richard371]

Its actually not the gyro. The gyro just senses changes in motion. The accelerometer sense gravity and tells the gyro what is level. This is why if the accelerometer is off by 3 the gyro is too.

Apple is using the same chip for the gyro as the iPhone 5. They switched to a less accurate accelerometer in the 5S.

What gets me is Apple is touting the new motion processor and put a level app in with the compass. It amazes me how this got by testing.


http://www.insideactivitytracking.c...ate-accelerometer-and-gyroscope-measurements/

"With the iPhone 5s, Apple changed producers for its accelerometer component. According to teardowns by iFixit and EDN, the iPhone 5 used the LIS331DLH 3-axis accelerometer and the L3G4200DH gyroscope, which are both made by STMicroelectronics. According to a Chipworks teardown, the iPhone 5s (see the M7 teardown) uses a gyroscope component from STMicroelectronics, but Apple switched to Bosch Sensortec for the accelerometer, using the BMA220 3-axis accelerometer. According to the companies’ websites, the old accelerometer was capable of higher data output than the new accelerometer (16 bit output compared to 6 bit digital resolution). The Bosch accelerometer also has more typical output noise and a higher Zero-g Offset than the STMicroelectronics component–two aspects also contributing to the lower level of accuracy in the iPhone 5s. This new accelerometer might be a source of users’ issues measuring levels."

I wonder if Tim has a crooked one lol?

 

[Sodner]

Use the included iOs compass app, swipe to page 2. Put your phone flat on some level table. Mine shows -2. Rotate the phone keeping it flat on the table. Mine shows -2 in every orientation. Tap to set to 0 at some orientation. Rotate 180 degrees. Mine then shows -4.

My phone level is broke - something is wrong.

One way to check calibration of any level is to check for level then reverse the level. If something is actually level it will show 0 both orientations.

Try the compass. Compare it to another one. It's broke as well.

 

[avanpelt]

The compass appears to be off by 8-10 degrees, while the inclinometer is consistently incorrect by 2 degrees on level services.

Sorry to be *that* person; but I think you meant to say "surfaces".

 

[lostngone]

This isn't an issue with iOS 7 - its an issue with the iPhone 5s and 5c which exhibit the issues quite often.

I think it is an issue with iOS 7 and power saving with the new devices.

If Apple is powering down the accelerometer when not being used to save battery life then every time an app needs to use the accelerometer it will need to be calibrated.

 

[flat five]

How do we know the Stanley level is 'level'?

I would like to see the same test done with DeWalt or some other brand.

My iPhone reports the level fine on iOS 7.

you can check if a level is reading true by centering the bubble, draw a line, turn the level around, then see if the line/bubble match.. if they don't match, the level is wrong.

 

[flat five]

View attachment 438182

maybe hard to tell from the angle you shot the bubble from but from where i'm sitting, that looks right.. as in, the bubble isn't exactly in the middle and it's saying the shelf is slightly tilted (the right side is lower).. same thing the phone is saying.

i think this thread may be more about people not knowing how to use a level accurately

(though a 3' wide shelf at 2º tilt is 1.25" lower on one side.. the shelf probably isn't that far out of whack)

 

[anthony11]

I'm not sure that this is anything new. The compass on my 3GS was off more often than it was correct. I would push the orientation button in Maps, and the streets would point off at around 30 degrees angles to where the street actually went.

If I would orient the phone to point straight North, and then move it 180 degrees it would NOT indicate straight south. I demonstrated it to the Genii but they claimed both that it was "within spec" and alternatively, that they couldn't test it because the compass would only work outside of a building. They did nothing for me.

My first thought is that it shows magnetic north without deviation correction, which is only "incorrect" if it *claims* to show geographic north.

 

[BurgDog]

My first thought is that it shows magnetic north without deviation correction, which is only "incorrect" if it *claims* to show geographic north.

Need to go into settings/compass and enable "Use True North"

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i think this thread may be more about people not knowing how to use a level accurately

Those of us who do know how to use a level are seeing the problem.

 

[Sym0]

This is not a big deal, the fact that Apple has not provided a simple calibration procedure at the software level is a bit strange. No electronic level/angle/inclinometer/EDM is precise, but simple checks can be made to see how much it is out and then split the difference to calibrate.

As mentioned above, you can test a $2 Stanley level through to a $60K Robotic Theodolite using the same method, measure something one way, then again on 180 degree face. Split the difference (there will always be a difference, depending on how accurate the measuring device can measure to) and add that diff to the original measurement and you have the precise measurement.

A software level test should be able to make this obs and add it to all measurements. This is how the $60K Jiggas work, so a $700 iPhone? Should be possible.

 

[tbrinkma]

Uhh, can't you "set" 0??

If you set it on a table and tap, the level resets to 0....

I may be wrong.

That works while you're still using the app, but it doesn't 'stick' between uses.

So long as the hardware reliably reports the same value to the software, it's something that *can* be calibrated in software. I suspect it will involve a long-term fix on the production line when they figure out the cause, combined with a software update to fix the devices currently exhibiting the issue.

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20 pages late MacRumors. Nice job!

And yes people this is a real problem. It can affect the sports/exercise functionality (M7 Chip), many games, panoramic photos, etc. The phone does not know what level is, where north is. And they are all off to varying degrees. This is not a "your holding it wrong" fix. Its a potential recall of "x" million phones type problem.

It's incredibly unlikely that there will be a recall over this. If it were providing inconsistent readings, that would be a recall issue. Instead, it is providing consistent, but incorrect, readings. That can be fixed with a software patch once they identify the root cause.

 

[BurgDog]

Error different based on phone edge used

Laying my phone flat on some surface gives me a constant -2 error that cannot be calibrated out. Using any of the phone edges on the same surface gives me a 0 error.

 

[tbrinkma]

You are wrong, by tapping the level you are performing a differential calculation function, not a calibration.

Technically, that's all calibration is. Since the sensors are reporting a consistent result, a permanent recalibration would fix this issue, and that can be done in software. It is extremely unlikely, however, that Apple will release *that* fix before they've identified and fixed whatever the underlying hardware or assembly issue is.