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OverrRyde

join:2007-04-10
Waterdown, ON
Reviews:
·Start Communicat..

Asus tablet issue with gyro

Hi guys, not sure if right forum but giving it a shot!

i have an Android Asus TF300 that i dropped yesterday, not from very high, maybe 2-3ft max. it is in a protective sleeve.

Now the tablet works fine, nothing was broken, however, the screen rotate no longer works.

I did verify that the auto-rotate option is enabled and it is and also tried an app that checks the sensors, i think it is Androsensor, and out of the 3 axis (x-y-z), they all move except the y axis, it does not move. All others show a value change when i tilt/move the device but the y axis does not move at all, stuck at something like 19.0131 -insert random number

Do you believe i actually broke the gyro inside from that fairly "gentle" fall? anyone ever had this happen before?

thanks!



shdesigns
Powered By Infinite Improbabilty Drive
Premium
join:2000-12-01
Stone Mountain, GA

It is not a gyro, but a MEMS sensor.

You might have broken it or its connection to the main board.



OverrRyde

join:2007-04-10
Waterdown, ON
Reviews:
·Start Communicat..

said by shdesigns:

It is not a gyro, but a MEMS sensor.

You might have broken it or its connection to the main board.

that's what i was thinking, but would that not cause all axis to be defective or not get a reading from the sensor app instead of just the Y axis not responding?

public

join:2002-01-19
Santa Clara, CA

said by OverrRyde:

that's what i was thinking, but would that not cause all axis to be defective or not get a reading from the sensor app instead of just the Y axis not responding?

Each axis probably has a separate accelerometer.
You broke one by exceeding max rating. It does happen.


OverrRyde

join:2007-04-10
Waterdown, ON

ohh i think i understand

the fall/impact caused the accelerometer to "bust" basicly.

wow, that's shitty! and because the device is unlocked i can't send it to Asus for repair... guess im outta luck! :-S



Cho Baka
Premium,MVM
join:2000-11-23
there
kudos:2
reply to OverrRyde

is there any sort of restore or hard reset you can try?
--
The talented hawk speaks French.



aurgathor

join:2002-12-01
Lynnwood, WA
kudos:1

1 edit
reply to shdesigns

The sensor is probably I2C/SPI, and so it's the sensor that get busted, not the connection.

Not sure what's there internally, but if there's a moving element that could get stuck, the OP could try to unstuck it with an opposite force.

Alternatively, unless it's a BGA, the sensor can be replaced. (at last in theory )

quote:
Each axis probably has a separate accelerometer.
You broke one by exceeding max rating. It does happen.
Since there are quite a few 3D accelerometers on the market, I think that's very unlikely -- it makes no sense to use 3 for cost reasons.

--
Wacky Races 2012!

TheMG
Premium
join:2007-09-04
Canada
kudos:3
Reviews:
·NorthWest Tel

said by aurgathor:

Since there are quite a few 3D accelerometers on the market, I think that's very unlikely -- it makes no sense to use 3 for cost reasons.

There are 3 distinct/separate sensing elements on the same chip. One for each axis.

It's quite interesting how they are made. The structure looks like interleaving combs, on a microscopic level. The middle set of comb fingers is allowed to move (held by tiny springs) when subjected to a force. The whole thing acts like a capacitor, as such the capacitance changes as the movable element moves when force is applied to it.


jrs8084
Premium
join:2002-03-02
Statesville, NC
kudos:1
Reviews:
·AT&T U-Verse
reply to OverrRyde

said by OverrRyde:

ohh i think i understand

the fall/impact caused the accelerometer to "bust" basicly.

wow, that's shitty! and because the device is unlocked i can't send it to Asus for repair... guess im outta luck! :-S

Even if it weren't unlocked, I would question sending it back. Don't get me wrong-I have a few ASUS products and have recommended them. But, you have to know what you are getting into. You get a good deal because they cut big time on service. You pay shipping, they make it difficult to get an RMA, they have a reputation to deny repairs because of damage (your case) etc, sometimes your hardware never shows up in their system, etc. They end up fixing it, but it takes a few weeks.

Having seen their RMAs which boldly lists all the reason they will deny fixing your machine (and the obviously disgruntled attitude of the workers) my guess is that you would spend $ shipping it to be told no.


OverrRyde

join:2007-04-10
Waterdown, ON
Reviews:
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reply to OverrRyde

jrs8084 - that's interesting, I've had to email with Asus luckily but I do like their products too.

Anyhow, surprise! I again dropped it from an even lower height than before and now it works! I guess aurgarhor was right!

Thanks for the info guys!


lutful
... of ideas
Premium
join:2005-06-16
Ottawa, ON
kudos:1

Click for full size
said by OverrRyde:

Anyhow, surprise! I again dropped it from an even lower height than before and now it works! I guess aurgarhor was right!

It was a really bad idea to drop your tablet again.

I used to work at ST in 1999/2000 when first generation mems sensors were being developed. Designers want device to be essentially obliterated by shock before mems elements could be damaged. Please have a look at the maximum g specs of current generation and rest assured the sensor was not damaged.

Their buggy "free fall" handling algorithm most probably caused the original problem after first drop and apparent fix after second drop. It is possible that a hard reset would have done the same.


OverrRyde

join:2007-04-10
Waterdown, ON
reply to OverrRyde

hehe it was not dropped on purpose the 2nd time! Its what happens when you try to use a tablet while holding a curious 5mth baby!


TheMG
Premium
join:2007-09-04
Canada
kudos:3
Reviews:
·NorthWest Tel
reply to lutful

said by lutful:

Their buggy "free fall" handling algorithm most probably caused the original problem after first drop and apparent fix after second drop. It is possible that a hard reset would have done the same.

I've heard that stiction of the MEMS sensor element is a potential problem when it hits its limit? Perhaps the MEMS sensor was simply "stuck". Is this true/possible?

lutful
... of ideas
Premium
join:2005-06-16
Ottawa, ON
kudos:1

said by TheMG:

I've heard that stiction of the MEMS sensor element is a potential problem when it hits its limit? Perhaps the MEMS sensor was simply "stuck". Is this true/possible?

Yes, if you apply greater than maximum g spec shock, the cantilever arms will vibrate all the way down to the substrate. But they have to somehow get stuck and then remain stuck for more than a few microseconds. Really difficult unless you attach one to a bullet or missile.

Very high humidity and pollutants could cause stiction in mems microphones and some sensor designs which allows outside air and gases to come into the cavity. Otherwise this is a problem mainly during fabrication (due to processing liquids) and those chips are thrown out.


SmokChsr
Who let the magic smoke out?
Premium
join:2006-03-17
Saint Augustine, FL
reply to OverrRyde

Not to steal the topic from the OP, but while on this subject, anyone know if an IPhone 4's max G force can be retrieved after the fact?

To make a long story short, my I4 took a fall last weekend, 150' from a tower onto coarse gravel. It was in an Otter box and survived with no obvious damage or malfunctions. Just curious what the sensors saw on impact.

PS I did notice a more rapid than normal battery discharge time after the fall, upon inspection I saw some slight damage to one corner of the battery. I just changed the battery out for safety (it is a lipo after all) and to see if it was the battery at fault for the quick discharge.


TheMG
Premium
join:2007-09-04
Canada
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Reviews:
·NorthWest Tel

said by SmokChsr:

Not to steal the topic from the OP, but while on this subject, anyone know if an IPhone 4's max G force can be retrieved after the fact?

The sensors would not yield any useful information as the sensors typically found in these devices have a very limited range.

Resolution is more important than range in such applications.

+/- 2G is pretty typical.

Although, if the event was recorded, it could provide a measure of the amount of time that the device was in free-fall, thus giving an indication of how high it was dropped from. But that's about all the information you'd get.


aurgathor

join:2002-12-01
Lynnwood, WA
kudos:1
reply to SmokChsr

As per that is a 2/4/8G device, so the max it can read is +/- 8G.

One possible reason to record max G is for warranty purposes, and with a device like the iphone I don't think that's very important -- if it it is subjected to a high enough G against a hard surface, it will break.

That may be more important in case of hard drives where there may be no easily visible signs of high G that can result in a malfunction.
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