iPhone 6 and 6 Plus Equipped With Two Accelerometers for Power Management, Improved User Experience

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Original poster
Apr 12, 2001
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Apple has opted to equip the iPhone 6 and 6 Plus with two separate accelerometers, as discovered in Chipworks' comprehensive iPhone 6 and 6 Plus teardown. There's a three-axis Bosch BMA280 accelerometer and what Chipworks believes is a MPU-6700 six-axis accelerometer from InvenSense.

According to Chipworks, Apple may have decided to incorporate two accelerometers into the iPhone 6 and 6 Plus to both minimize power consumption and "improve the overall user experience."

The InvenSense accelerometer has a range of functions, allowing it to operate in several different modes, but it can draw more power than the Bosch accelerometer due to its higher sensitivity. The maximum sensitivity of the InvenSense is at 16684 LSB/g, much higher than the Bosch's 4096.

The InvenSense device can operate as a six axis inertial sensor, or as either a three-axis gyroscope or a three-axis accelerometer. It is rated to consume 3.4 mA in the six-axis mode, 3.2 mA in the gyroscope mode and 450 µA in the accelerometer normal mode. By contrast, the Bosch device operates as a 3-axis accelerometer only and it consumes 130 µA of current in the accelerometer normal mode. Both devices offer two low power levels of operation for the accelerometer function. The InvenSense device actually consumes less current in its lowest power mode, with a 1 Hz update rate.

The main benefit of the InvenSense is full six-axis integration of the data by the on-chip digital motion processor (DMP). This will provide a direct benefit for gaming and other applications that need sophisticated inertial sensing capabilities. In addition the InvenSense provides significantly higher sensitivity than the Bosch device. The price however, is higher power consumption.
The Bosch accelerometer is able to operate at a lower power than the InvenSense and it has a "much faster" cold start up time, at 3ms compared to 30ms, allowing it to be used when complete six-axis integration is unnecessary. Chipworks speculates that it may be used for tasks where higher sensitivity is unneeded, perhaps for rotating the screen from landscape to portrait mode or for pedometer functionality.

According to Chipworks, the inclusion of two accelerometers in the iPhone 6 and 6 Plus is an example of Apple's "elegant engineering." A single InvenSense accelerometer would have enabled the device to work perfectly well, but the addition of the Bosch accelerometer allows for lower power consumption in the appropriate situations.

Article Link: iPhone 6 and 6 Plus Equipped With Two Accelerometers for Power Management, Improved User Experience
 

iLoveiTunes

macrumors 6502
Feb 26, 2011
268
511
I am glad that we are finally getting back on track with actual iPhone specs and NOT the bendability results.
 

McGiord

macrumors 601
Oct 5, 2003
4,535
287
Dark Castle
Now...will this explain why the screen rotation with iPhone 5 running iOS 8 is having some irregular performance???
 

teknikal90

macrumors 68040
Jan 28, 2008
3,149
1,478
Vancouver, BC
It is exactly this type of clever engineering which is why Apple don't need to include 2Gb of ram just to look good in the specs race.
they dont need more ram
but they will
ie. 2 or three years from now
the iphone 5 is still very much future proof, 2 years after launch.
probably will still work fine on ios 9 too.

has a lot to do with the fact it has the same 1gb ram as the iphone 6.
 

Patriot24

macrumors 68030
Dec 29, 2010
2,811
793
California
OK, so I got the obvious, witty Android joke out of the way. Here's the real point:

A lot of people look at these devices being released every year with the sense that all these companies do (LG, Samsung, and others included) is slap the same old components on the inside and change the case or screen size. In reality, they are re-architecting a lot of the technology every year or two. This is not easy to do.

Only when we get tear downs and such do we get the full story of everything going on inside the shell. These guys are doing amazing work to move technology forward. The result is better devices and increased convenience/utility for the user.

The engineers that put this particular solution together aren't going to be recognized or win any awards, but they're doing great things.
 

Glassed Silver

macrumors 68020
Mar 10, 2007
2,096
2,558
Kassel, Germany
It is exactly this type of clever engineering which is why Apple don't need to include 2Gb of ram just to look good in the specs race.
Hmm, well then explain the very frequent reloading of Safari tabs, apps losing their state when multitasking between more than just 2-3 apps, don't dare to use background tasks like music players or something...

There is only so much you can get out of 1GB of RAM.

Glassed Silver:mac
 

The Mercurian

macrumors 68020
Mar 17, 2012
2,029
2,286
In 1996 I did a work placement in a semi-con company that was making semi-con accelerometers and they raved about them saying they would be the thing of the future - they have since gone bust - but I guess they were right!
 

milo

macrumors 604
Sep 23, 2003
6,888
518
It is exactly this type of clever engineering which is why Apple don't need to include 2Gb of ram just to look good in the specs race.
2G ram would't be for the specs race, it would be for Safari tabs not constantly reloading. Needing less ram is the poster child for apple's software engineering dropping the ball.
 

janderson0719

macrumors 6502
Aug 25, 2011
403
19
All I know is I'm really impressed with the 6+ battery.

What a huge upgrade from the iPhone 5 I had previously.
 

coolfactor

macrumors 601
Jul 29, 2002
4,643
4,680
Vancouver, BC
Hmm, well then explain the very frequent reloading of Safari tabs, apps losing their state when multitasking between more than just 2-3 apps, don't dare to use background tasks like music players or something...

There is only so much you can get out of 1GB of RAM.

Glassed Silver:mac
So maybe the app developers need to implement disk-based caching instead of consuming valuable RAM when the app is not in active use? I don't think more RAM is really the solution to these problems, such as how Safari behaves.
 

rsocal

macrumors 6502a
Sep 22, 2008
738
0
Southern Ca
OK, so I got the obvious, witty Android joke out of the way. Here's the real point:

A lot of people look at these devices being released every year with the sense that all these companies do (LG, Samsung, and others included) is slap the same old components on the inside and change the case or screen size. In reality, they are re-architecting a lot of the technology every year or two. This is not easy to do.

Only when we get tear downs and such do we get the full story of everything going on inside the shell. These guys are doing amazing work to move technology forward. The result is better devices and increased convenience/utility for the user.

The engineers that put this particular solution together aren't going to be recognized or win any awards, but they're doing great things.
Unfortunately, for so many people, it's never enough!

I hate to even say it but, the "it bends" shows the mentality of people who just don't get what these people are doing!:apple:
 

ChrisCW11

macrumors 65816
Jul 21, 2011
1,037
1,432
OMG get over the RAM debate

$0.05 more of extra RAM in a phone never hurt anybody, except Apple's bottom line, which is why they don't simply put 8gb of RAM in their phones by now.

I mean why did Apple go to 64bit mobile processing? It certainly is NOT necessary for MOST mobile applications, and there is many that have suggested even the iPhone's 5s A7 CPU is woefully underutilized, so why did Apple have to rush out a phone with an overpowered A8 CPU this time around? Certainly it looks much better on paper to see a CPU version bump and to boast about how many more times powerful the new iPhone 6 is over the previous generations.

So if you are going to suggest to me that Apple is not bumping up the RAM because they don't believe it's technically necessary and that Android phones are just doing so for prestige or necessity, bull-****. Apple started the whole "my specs are better then your specs" game a LONG time ago.

Apple most likely hasn't found a financial reason to spend more money on their phones to add the extra RAM, but you can be sure the moment Apple decides that a phone needs 32gb of RAM, then Tim Cook will be on stage proudly boasting about how the new iPhone X is so much better than all those phones with only a paltry 4gb of RAM.
 

AppleInLVX

macrumors 65816
Jan 12, 2010
1,093
511
Is this why my phone keeps thinking that my photos are portrait even though I'm holding the phone landscape? :confused:
 

ghettochris

macrumors 6502a
Feb 19, 2008
774
0
$0.05 more of extra RAM in a phone never hurt anybody, except Apple's bottom line, which is why they don't simply put 8gb of RAM in their phones by now.
I'm not sure exactly how much more, but running eight gigs of RAM takes more power than running one gig. There are some cons involved, mostly cost and power.
 

nagromme

macrumors G5
May 2, 2002
12,546
1,195
And here's what accelerometers get you WITHOUT elegant engineering:

http://gameovenstudios.com/bounden-on-android-delayed/

"We have been developing Bounden for Android alongside its development on iOS, and have tested the game on a number of devices. It was only a week ago that we started expanding our list of test devices, after we quickly discovered that: a) some devices had ‘broken’ gyroscopes that didn’t work on all axis, b) that some devices were faking gyroscopes by mixing and matching the accelerometer data with compass data, or c) that some devices did not have a gyroscope at all. ... At this point, we are left with one option: whitelist Android devices one by one and release the game when we feel good about the list."

http://www.wired.com/2014/08/hyperlapse-instagrams-new-app-is-like-a-15000-video-setup-in-your-hand/

"Instagram hopes to develop an Android version [of Hyperlapse] soon, but that will require changes to the camera and gyroscope APIs on Android phones."
 

Glassed Silver

macrumors 68020
Mar 10, 2007
2,096
2,558
Kassel, Germany
So maybe the app developers need to implement disk-based caching instead of consuming valuable RAM when the app is not in active use? I don't think more RAM is really the solution to these problems, such as how Safari behaves.
Virtual memory is the last thing a flagship smartphone should make extensive use of for simple things like keeping a FEW apps ready to go as soon as I multitask back into them, let alone keeping more than 3 or 4 Safari tabs loaded.

Come on, we applaud Apple's genius for including 2 accelerometers to save battery life, but then we accept 1GB of RAM in 2014?
No, just no.

I'll likely update sooner or later, because I can make use of quite some features that will be new to me as iPhone 5 owner and my contract allows for an upgrade soon, but I know damn well that with 1GB of RAM this will be one short-lifed phone in terms of performance on the second next iOS version.

Glassed Silver:mac
 
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