iPhone 5s Motion Sensors Are Totally Screwed Up

The iPhone 5s Motion Sensors Are Totally Screwed Up

Since the iPhone 5s landed in the hands of new owners a few weeks ago, there have been reports that on-board sensors like the gyroscope, compass and accelerometer haven't been working properly on some devices. We've confirmed the new iPhone's failings on our own. It's not just off. It's embarrassing.

We tested two iPhone 5s units running the latest version of iOS 7 against the iPhone 5, as well as against real-world measuring tools to find out if the new iPhone's sensors are off, and if they are, by how much. In most cases, we used the iPhone's built-in iOS 7 apps for measurements, working under the assumption that Apple would properly calibrate its hardware to work with the software of its own design. We were wrong.


The iPhone 5s Motion Sensors Are Totally Screwed Up

In the GIF and still image above, you see a pretty dramatic illustration of the difference between the iPhone 5s internal inclinometer readings and a real measurement of inclination. A simple Stanley spirit level tells the whole story: The iPhone 5s level readout in the iOS 7 compass software read 2-3 degrees off in our tests, while other users are reporting that the level is off by as many as 4-6 degrees. We performed the same test with an iPhone 5, and readout was almost perfect, indicating that hardware is at least partly the culprit. That also means a fix might not be as easy as an OTA firmware update.

The iPhone 5s Motion Sensors Are Totally Screwed Up

We also tested the level using the free iHandy Level app to similar results. In all cases, we were sure to keep the side of the iPhone flush to the level.

Two degrees might not seem like much, but it's actually a reasonably big deal. If you use this level to set up shelves (or tackle any other home improvement gig) you'd end up with a mess.


The iPhone 5s Motion Sensors Are Totally Screwed Up

As with the simple inclinometer measurements, the iPhone 5s gyroscope readings show a discrepancy between the iPhone 5 and iPhone 5s. This shouldn't be a surprise since it's the same piece of hardware as the inclinometer, just with an added third dimension. Above is what happened when I tossed both phones on a level table. The iPhone 5 reads level, while the iPhone 5s reads -3 degrees off level.

The iPhone 5s Motion Sensors Are Totally Screwed Up

Why does this matter? Because a wonky gyroscope is going to totally screw up gaming. Check out the drift when I'm playing EA's Real Racing 3. The green light flashes, the car goes left. The phone is still and level.


The iPhone 5s Motion Sensors Are Totally Screwed Up

The compass is a little more challenging to test, because the numbers on both the iPhone 5 and iPhone 5s tended to jump around bit. After getting the readings steady, though the two phones consistently measured 8-10 degrees apart. It's also worth noting that on the iPhone 5s, the compass application was prone to either freezing up or giving wonky readings that could only be fixed by killing and restarting the app.

The iPhone 5s Motion Sensors Are Totally Screwed Up

When comparing the measurements against an actual compass, neither iPhone's compass points to the same magnetic north as the real tool; however, the iPhone 5 clearly has a more accurate measurement.

This compass shortfall won't have you confusing east from west when you get out of the subway. But for more detailed mapping and way-finding apps, a 10 degrees disparity could impact what an app thinks you're doing and which way you're going. You probably shouldn't be using an iPhone compass to navigate the woods or set your course at sea anyway -- but, yeah, don't do that.


The iPhone 5s Motion Sensors Are Totally Screwed Up

We did a brief test on the new iPhone's accelerometer data, and preliminary results seem to indicate that the 5s is registering way more latent motion than the iPhone 5. The above images show the readouts from the accelerometers of both phones sitting flat on a level desk. Our testing isn't conclusive here, but it's worth noting because the discrepancy is in line with those seen in tests of the other sensors.

Again, you can expect this to screw up gaming as well as readings on motion-based exercise apps, an especially unfortunate byproduct given how heavily Apple hyped its activity-tracking M7 processor (more on the hardware implications below).

What's going on, and what's the fix?

The faulty measurements from the iPhone 5s could either be a hardware problem or a software problem, and if you read through the experiences of users in the extensive MacRumors thread on the topic, there's an argument to be made for both.

The problem seems to be incredibly widespread, but it also affects different phones in different ways. If it were consistent across the board -- for example if the compass was 2-degrees off for everyone -- then it would be easier to pin the blame on iOS 7. The solution to the current sensor woes, then, could be as simple as a firmware fix to make the calibration more accurate.

As richard371 in the MacRumors thread points out, though, the inconsistency of the problem suggests -- and the fact that it doesn't show up on an iPhone 5 running iOS 7 -- that the hardware isn't being properly calibrated in the factory, and that means that there are millions of phones out there that might never be exactly right. That's a huge problem. (Some users have reportedly had luck taking their phones back and swapping them for others -- but just as many users report making the exchange and getting another malfunctioning unit.)

If it's indeed an underlying hardware problem, Apple will probably quietly resolve the issue with a tweak on future production units of the 5s, which still leaves millions of potentially defective units in circulation. It's possible that Apple could push a calibration tool or software fix that accounts for the inconsistent hardware performance in existing handsets, but it's very unlikely that the company will take all of these phones back (or that enough people will notice/care enough to get a new one.

Either way, it's a problem, whether you're a gamer, a home-improver, or someone who just wants their phone to work as advertised out of the box.

Pictures: Nick Stango



    I cant seem to replicate these issues.

    Oh wait, that's because i have a Nokia 920.

      And no apps to use on it because developers hate it!! The gaming won't be calibrated properly but at least we will get the games.

      worst 8 months I ever spent with a phone hands down. (also went through 3 replacements first for faulty proximity sensor/loose parts inside and yellow buttons) and the other two because the phone bricked itself doing a factory reset)

    Yeah this seems like a major stuff up....until I realise I never ever have even opened the compass or use my phone as a level or any of that junk. BUT...for the (small) amount of people who rely on those things....quite the annoyance...I assume.

      Yeah you're right. So long as I'm not personally hampered by a shortcoming in a phone then its not really a problem.

      do you play games that use the accelerometer or gyro etc?

        unless the game tests how perfectly level you can hold the phone, is it really likely to matter all that much? If you were playing the real racing gif above I doubt it'd really take that much to compensate, nor would it be likely to be all that noticeable.

    Only in reply to ea's real racing .gif

    I just want to confirm something, is the car a front wheel drive car that is driven for the gif?

    What it looks like to me is that 1/2 to 3/4 throttle is used off the line for the start, there is a small amount of torque steer( as there could/should be in real life depending on differentials, suspension, power setup etc) off the line which you do not counter, then the car tracks straight till it hits the ripple strip. It then moves slightly and continues to do so while on the grass. From my limited real life racing experience and from playing many computer games this looks like about right for the simulation.

    Even if its not a front wheel drive car there are many things like a small amount of wheelspin that need steering input to correct and when the phone is not being moved it tracks straight when these factors are removed.

    Just my 2cents....

    The gyro may me broken but this isn't a great example.

    Last edited 04/10/13 9:24 am

      That game does not take that into account....if you do not move the steering wheel/gyro the car will go directly straight

        I'm more interested in how you created those large animated gifs (if not with photoshop) :)

    I look forward to the eventual "It's not an issue, you just need to get over it" rhetoric from Apple.

      One of Tim Cook's legs is longer than the other. "Looks fine to me. You're all holding it wrong!"

      ... or perhaps the iPhone 5s is just so advanced that it highlights how wrong everything else is...?

      its nothing wrong with the iphone

      gravity is broken

        Gravity...pulling the iPhone to its grave

    Actually, it looks like the 5s' compass is more accurate, if only slightly.

    The sensors have never been accurate. Same story on my 3GS, 4 and 5s.

    I also doubt the integrity of some of the testing done in this article. In my experience the calibration/zeroing phase is crucial to obtaining the most accurate measurements possible and this was not discussed at all in the article.

    If the phone is placed on a level surface, zeroed, and then tilted from that position along a single axis/plane it seems to produce somewhat accurate and repeatable/predictable results. If the phone is rotated without being tilted at all, you will see that it doesn't hold zero until it's back in the same orientation as it was when it was zeroed.

    What this suggests is that the absolute measurement ability of the phone is flawed, but the relative measurement ability is solid. Just like a wii controller or wii u game pad needs to be periodically left flat somewhere to calibrate, so does the iPhone.

    An experienced developer will be coding some kind of regular calibration in to the game, most probably around the loading screen before a level begins when the phone is being held in the natural zero position for the game.

    I don't think anything you have written in this article supports your argument the phone will have problems in a gaming scenario.

    Tip of the iceberg! I have noticed varying degrees in "accuracy" (better described as difference) in all my phones. I just put it down to natural variation. This case looks to be a bit more consistently wrong, however.

    I haven't found the compass accurate on any smartphone. If you look closely, small movements are not picked up by the gyro, hence the compass doesn't update and orient.

    I don't know if anyone else realises this but in the app, you can tap on the screen to calibrate the level to a custom zero point. So if it's be reset by accident by the user, it will appear incorrect.

    Magnetic North or True North...?

    maybe needs a calibration program which can save an offset which is used by the accerometers. probably a whole bunch of offsets.
    Each device would have an intrument error and good instruments can be calibrated. You can't just send out millions of instruments and expect them all to be exact. Same applies to kitchen scales and electric verniers etc.
    The compass app makes you roll a ball in a circle to calibrate it.

    Last edited 04/10/13 12:39 pm

    "It’s possible that Apple could push a calibration tool or software fix that accounts for the inconsistent hardware performance in existing handsets, but it’s very unlikely that the company will take all of these phones back (or that enough people will notice/care enough to get a new one."


      Uh oh. That means all the comments are part of the parenthesised area too!)

      Whew. That's better.

    HELP, I'm lost at sea! Shouldn't have trusted the iPhone

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