Timeline for What makes smartphones tilt-sensitive? Will they retain this ability in zero-gravity conditions?
Current License: CC BY-SA 3.0
58 events
| when toggle format | what | by | license | comment | |
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| May 21, 2017 at 3:01 | review | Close votes | |||
| May 22, 2017 at 3:02 | |||||
| May 15, 2017 at 20:18 | comment | added | user541686 | @Fattie: That doesn't make any sense though. Even on Earth if I lie down on my side on my bed and hold my phone, it will rotate the screen, whereas the same relative position to me will not result in a rotation if I'm standing up. So unless you claim the behavior is already "wrong" on the ground, in which case it's obviously less likely to be "right" elsewhere, clearly "correct" behavior is not relative to the person, it's relative to gravity. So it doesn't make sense to ask what it is in zero gravity... | |
| May 15, 2017 at 13:30 | comment | added | Trevor_G | @JeannePindar that's not what I was saying, I was intimating that when you use accelerometers, the first thing you do on power on is calibrate them and remove the offset caused by the gravitational effects on the mass involved. After that it's about the delta. This would be the same in any environment. | |
| May 15, 2017 at 13:28 | comment | added | Baldrickk | @Mehrdad the enemies gate is 'down' | |
| May 15, 2017 at 10:57 | comment | added | Fattie | Many of the comments here are quite incorrect. "They have accelerometers."( it's a bit like saying "a car has brakes". Overwhelmingly, a car has a motor (yes, it also has brakes). Gyros are far more important in phones. *"[accelerometers] will not function correctly in zero gravity." Totally incorrect. Obviously from a physics stand point, they of course work in freefall. Practically you can get a hundred apps on the app stores, that are those "action sports" apps (put in your pocket while you do diving, ski jumping, whatever); they perfectly show your action during the freefall phase. | |
| May 15, 2017 at 10:54 | comment | added | Fattie | "What does it mean to even "work" in zero gravity? What is down?" it couldn't be more straightforward, Mehrdad. In an ordinary working spaceship, when the crew are sitting around, they refer to "down" as "the floor". No big deal. If (remarkably!) you were making a small game on a phone for space crew, let's say a steering wheel (some sort of car game).. Quite simply, you'd just define "down" as the rest state when the user was sitting there ("at the starting line"), and then detect "left and right turns" (twist on the z axis) from that basis (ie, the gyros would tell you that trivially). | |
| May 14, 2017 at 12:23 | answer | added | Fattie | timeline score: 8 | |
| May 14, 2017 at 8:10 | history | edited | paracetamol | CC BY-SA 3.0 |
added 6 characters in body
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| May 13, 2017 at 18:57 | comment | added | user541686 | What does it mean to even "work" in zero gravity? What's the definition of "down"? "Toward Earth"? | |
| May 13, 2017 at 15:39 | comment | added | Jeanne Pindar | @Trevor if you can (even theoretically) detect the difference between gravitational acceleration and other acceleration, you need to contact your nearest physics department immediately. That would be a significant development! | |
| May 13, 2017 at 12:26 | comment | added | JDługosz | «There isn't much a phone can do to help protect itself when dropped so I doubt they added anything special to cope with the situation.» but I would totally pay for an app that made the phone scream when falling. | |
| May 13, 2017 at 2:51 | comment | added | uhoh | Good question! I've linked here in How do iPads on the ISS know which way is “up” for their users?. | |
| May 13, 2017 at 0:13 | history | edited | bitsmack | CC BY-SA 3.0 |
Added tag, fixed small typo
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| May 12, 2017 at 23:51 | answer | added | bitsmack | timeline score: 10 | |
| May 12, 2017 at 19:46 | comment | added | Fattie | "The feature will not function correctly in zero gravity" this is completely wrong. the usual software app creators write will likely not function in zero g. | |
| May 12, 2017 at 19:44 | comment | added | Fattie | there are a number of utterly different devices at work; that seems to be a basic confusion in this QA. | |
| May 12, 2017 at 17:01 | answer | added | user_sp | timeline score: 0 | |
| May 12, 2017 at 15:15 | comment | added | njzk2 | @paracetamol there is grammar girl: quickanddirtytips.com/education/grammar/… (not sure if you count that as a good reference, though) | |
| May 12, 2017 at 14:52 | vote | accept | paracetamol | ||
| May 12, 2017 at 14:52 | comment | added | paracetamol | @njzk2 Utterly shocked [I'll be looking for a better reference though, just to confirm that ;) ] | |
| May 12, 2017 at 14:49 | comment | added | njzk2 | that's not what begging the question means, though: begthequestion.info | |
| May 12, 2017 at 14:46 | comment | added | FreeMan | And I'll give myself a comment down-vote for incorrectly and redundantly using "correctly"... meh indeed! | |
| May 12, 2017 at 14:44 | comment | added | paracetamol | @Free Meh... :3 | |
| May 12, 2017 at 12:59 | comment | added | FreeMan | I'm giving you a +1 on your question simply for correctly spelling "For all intents and purposes" correctly, especially as a high school student! The rest of it is good, but boy did that jump out at me, congrats! | |
| May 12, 2017 at 5:35 | history | edited | paracetamol | CC BY-SA 3.0 |
added 8 characters in body
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| May 12, 2017 at 0:10 | review | Close votes | |||
| May 14, 2017 at 15:52 | |||||
| May 11, 2017 at 16:52 | comment | added | user98663 | The XBox 360 game console can be operated either lying flat on a table or standing vertically. It would detect this orientation not with an accelerometer but by a very simple two-position tilt switch. The sensor was basically a set of contacts positioned such that a tiny gold-plated metal ball would make or break one of two mutually-exclusive switches. And thus it could figure out which way up it was. It used this information to (among other things) select which of two icons would show up in notification messages. Pretty pointless but it was cheap and easy to implement. | |
| May 11, 2017 at 16:12 | history | tweeted | twitter.com/StackElectronix/status/862702007265763328 | ||
| May 11, 2017 at 15:50 | answer | added | Trevor_G | timeline score: 10 | |
| May 11, 2017 at 15:02 | comment | added | Trevor_G | Not so sure the rotational information in all phones would work in the space-station though. Since, they are using G as the reference signal from each accelerometer, you don't need anything else to detect rotation since the G-Factor will change between the three axis accelerometers. So unless they have a different spin sensor they probably don't. Though I guess, doubling up on accelerometers, and enough math would give you the visibility. | |
| May 11, 2017 at 14:54 | comment | added | Trevor_G | @EugeneSh. indeed. Tilt would be referenced to the last known direction. That is, it would know it turned 90 degrees. but whether the displayed image is shown in the right direction would be indeterminate. For an ideal system, it would not matter, since everything would be cumulative from when the thing first came to life, was powered up, and was presumably self-calibrated. In reality, like a gyro, occasional reference point fixing would be required in a weightless scenario. | |
| May 11, 2017 at 14:53 | comment | added | Eugene Sh. | @JorenVaes I would use SSD instead :) | |
| May 11, 2017 at 14:47 | comment | added | Joren Vaes | This raises the question: Do laptops on the ISS require special firmware, to prevent the harddrive constantly going into drop-protection mode? | |
| May 11, 2017 at 14:44 | comment | added | Trevor_G | Yup, what @Andrew is saying is what I was saying too. The fact that your cell phone might not work the same in the international space station, is more a factor of how the software works, not how the accelerometers work. Though the software would probably indicates the phone has been thrown up rather than dropped. | |
| May 11, 2017 at 14:43 | comment | added | user57037 | I am aware of the drop detection. I don't think it is out of the question that programmers would anticipate operation in a weightless environment, though. In particular, if the orientation is not strongly determined by something close to 1g, the device may simply suppress display orientation changes. | |
| May 11, 2017 at 14:31 | comment | added | Eugene Sh. | @Andrew is right. If you look at some accelerometer chips you will see some pins for the "drop detection" interrupt. | |
| May 11, 2017 at 14:29 | comment | added | Andrew | @mkeith If the phones software does have code specifically for a zero gravity situation it will assume the phone has been dropped. Some laptops with mechanical HDDs will park the drive in this situation to avoid data loss, HDDs are better able to withstand high G forces when parked. There isn't much a phone can do to help protect itself when dropped so I doubt they added anything special to cope with the situation. | |
| May 11, 2017 at 14:27 | comment | added | Eugene Sh. | @mkeith probably it will rotate the screen like crazy. You can simulate this behavior by dropping the smartphone from the Tower of Pisa :) | |
| May 11, 2017 at 14:24 | comment | added | user57037 | The tilt or orientation sensors basically assume that they are in a gravitational field. They measure the direction of acceleration and call that direction "down." If placed in a path or location where "down" does not exist, I expect that the sensor would not function correctly, but I don't know exactly what it would do or whether the firmware covers this operational mode. By now, I imagine someone has taken a smartphone into space. Would be interested to hear about it. | |
| May 11, 2017 at 14:20 | comment | added | Trevor_G | @mkeith yup I know. I'm just being pedantic. It's just that a TRUE accelerometer measures change in speed. Weight on a spring is something different. | |
| May 11, 2017 at 14:20 | comment | added | Eugene Sh. | BTW, you won't be able to feel any "tilt" as well in the weightless environment. Because there is no "straight" position defined there. | |
| May 11, 2017 at 14:18 | comment | added | Eugene Sh. | @Trevor But it won't be able to measure the tilt since there won't be any reference vector. | |
| May 11, 2017 at 14:17 | comment | added | Trevor_G | @pjc50 ya ya, but that is not relevant in a static situation. An accelerometer should still measure it's own acceleration in a weightless environment. | |
| May 11, 2017 at 14:17 | comment | added | paracetamol | @mkeith Great! I'll wait for a day (for the answers to pool in), and then I'll go about "accepting" an answer. I'm looking forward to yours ^_^ | |
| May 11, 2017 at 14:14 | comment | added | pjc50 | @Trevor have you heard of "acceleration due to gravity"? | |
| May 11, 2017 at 14:14 | comment | added | Trevor_G | @mkeith an accelerometer should not care about gravity. | |
| May 11, 2017 at 14:13 | comment | added | user57037 | Looks like a couple of other people are going to do a good job answering. But if I feel I still have something to offer after they answer, I will write an answer or comment on their answer. | |
| May 11, 2017 at 14:12 | comment | added | paracetamol | @mkeith You're probably at it right now, but... could you post that as an answer? [Since this sounds interesting, you'll get my upvote ;) ] | |
| May 11, 2017 at 14:11 | answer | added | Joren Vaes | timeline score: 99 | |
| May 11, 2017 at 14:09 | comment | added | user57037 | They have accelerometers. To an accelerometer, gravity looks the same as acceleration. This is how they sense orientation. The feature will not function correctly in zero gravity. You are correct that accelerometers have moving parts, however they are very small moving parts. Google accelerometer. Many smartphones also have something similar to a gyro to detect the rate of pitch, roll and yaw. Sometimes these sensors are called "angular rate sensors." The accelerometer is not good at detecting pitch, roll and yaw, but it is good at detecting orientation in a gravitational field. | |
| May 11, 2017 at 14:08 | history | edited | paracetamol | CC BY-SA 3.0 |
added 15 characters in body
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| May 11, 2017 at 14:08 | answer | added | pjc50 | timeline score: 17 | |
| May 11, 2017 at 14:08 | comment | added | paracetamol | @ks0ze Hypothetical situation, should've mentioned that, thanks! | |
| May 11, 2017 at 14:07 | comment | added | ks0ze | Zero-gravity doesn't actually exist, so are you talking about a weightless environment or hypothetical situation? | |
| May 11, 2017 at 14:06 | comment | added | Chris M. | Good information on micro electro-mechanical systems (MEMS) here as well. pcb.com/Resources/Technical-Information/mems-accelerometers | |
| May 11, 2017 at 14:06 | comment | added | brhans | Accelerometers measure acceleration due to gravity (and other forces). One accelerometer per axis. | |
| May 11, 2017 at 14:06 | comment | added | JIm Dearden | What you are talking about are accelerometers see digikey.com/en/articles/techzone/2011/may/… | |
| May 11, 2017 at 13:57 | history | asked | paracetamol | CC BY-SA 3.0 |