iOS App Acoustically Measures Distances Up To 25 Meters

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iOS App Acoustically Measures Distances Up To 25 Meters

Posted by samzenpus on Sunday November 13, 2011 @08:07AM from the new-tool-for-the-box dept.

n01 writes "A recently published app for the iOS platform uses the propagation of sound waves to measure distances of up to 25 meters in a dual device mode. The technique works through repeatedly sending a chirp signal from the master device to which the other (reflector) device synchronizes itself and then replies in a similar fashion. A novel combination of techniques has been engineered to enhance the robustness in noisy environments, such as using an optimum-autocorrelation-signal and semi-automatic frequency calibration together with an averaging over multiple cycles."

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Aliens by ae1294 · 2011-11-13 08:10 · Score: 1

Now you to can be a space marine up until the point the aliens get to you and all you got for xmas was a stinking ipod...
1. Re:Aliens by Anonymous Coward · 2011-11-13 08:38 · Score: 0
  
  The Aliens also need to have an app on their iOS too. What are the chances?
2. Re:Aliens by Anonymous Coward · 2011-11-13 08:40 · Score: 0
  
  There's an app for that.
Nifty by Anonymous Coward · 2011-11-13 08:11 · Score: 1, Insightful

But still an advertisement.
1. Re:Nifty by bonch · 2011-11-13 10:22 · Score: 5, Insightful
  
  So Slashdot can't report on anything, ever, if it's for sale somewhere. Got it.
2. Re:Nifty by Anonymous Coward · 2011-11-13 12:49 · Score: 0
  
  How about an app that can determine a girl's "true" cup size (minus the padding) from 25 meters? I'd get it.
  roxy
3. Re:Nifty by Meski · 2011-11-13 17:04 · Score: 1
  
  Size? it's ratio that's important. Think golden ratio, perhaps...
4. Re:Nifty by zevans · 2011-11-14 02:23 · Score: 3, Funny
  
  I strongly prefer empirical methods in this case.
  
  --
  "... and more and more now there are all kinds of electronic goodies available" -- Pink Floyd 1972
5. Re:Nifty by tehcyder · 2011-11-14 03:21 · Score: 0
  
  welcome to capitalism, fucktard. what progress did feudalism make again?
  Fuck off, even under capitalism there are rules about what is an ad and what is not.
  
  --
  To have a right to do a thing is not at all the same as to be right in doing it
6. Re:Nifty by Anonymous Coward · 2011-11-14 08:37 · Score: 0
  
  you took a really long time to respond. what i meant by "welcome to capitalism" is that innovation is in the form of salable products. something true since the industrial revolution, but not at all in feudal times.
XO (OLPC) by itamblyn · 2011-11-13 08:12 · Score: 5, Informative

http://wiki.laptop.org/go/Distance
Not impressive by girlintraining · 2011-11-13 08:12 · Score: 4, Interesting

That's not very impressive. Anyone who has two devices that are syncronized to a common timing source (which most cell phones are) can accomplish this. You just say "I started transmitting at x and you received it at y. x-y/speed of sound at sea level = your result. Now if it could be done with one device, and use doppler effect,etc., to map out the room and roughly what's inside it (like in Batman) then we'd be getting somewhere.

--
#fuckbeta #iamslashdot #dicemustdie
1. Re:Not impressive by grumbel · 2011-11-13 08:19 · Score: 4, Informative
  
  Yep, neat, but not exactly ground breaking. The OLPC had such an application for the last few years.
2. Re:Not impressive by Anonymous Coward · 2011-11-13 08:33 · Score: 0
  
  That's not very impressive. Anyone who has two devices that are syncronized to a common timing source (which most cell phones are) can accomplish this.
  You don't need even that, as you can see in the first video. Device A sends out a signal, device B sends the signal back after a certain delay. Device A can then calculate the distance, since the elapsed time is twice the travel time + the delay.
  Physics wise it's straight forward. Nevertheless, it's a nice idea and a nice project to bring that to reality with two devices like that (or any other smartphone, for that matter). :)
3. Re:Not impressive by Anonymous Coward · 2011-11-13 08:36 · Score: 2, Funny
  
  No no no no no. Apple first. Apple first. [rocks back and forth]
4. Re:Not impressive by Anonymous Coward · 2011-11-13 08:38 · Score: 1
  
  I seriously doubt they are using their clock times for this. Yes, they are synchronized to a common timing source, but to measure distance, you require sub-millisecond accuracy. Clock drift means the cell phone clock probably isn't that accurate, if it was even that accurate at the moment it was synchronized, which is also unlikely.
5. Re:Not impressive by Solandri · 2011-11-13 08:51 · Score: 5, Interesting
  
  Fun story. While I was at MIT/Sea Grant working on robot submarines, we'd lay an array of underwater beacons for navigation. To conserve power, they'd listen for a certain sequence of sounds from the sub, then reply back with their unique ping. The sub could measure the time it took to receive each unique ping, and thus determine its position by using the ping times and knowledge of where the beacons were. Kind of an underwater GPS. The beacons could last a year or more when used like this, which was a big deal because it was really annoying to locate and retrieve one just to load it with a fresh battery.
  
  On one particular deployment, we left the beacons because we were planning to return a few months later. When we got back, the beacons weren't working. We retrieved them and all the batteries were dead. So we recharged the batteries and redeployed them. After our tests were over, we left the beacons again. When we returned a couple months later, they were all dead again.
  
  Eventually we figured it out. The dolphins in the area had figured out the sound sequence used to make the beacons respond (probably just listened in on our sub). They thought it was pretty cool to get an acoustic response every time they used that code, so they'd been merrily chirping away during those months, draining our batteries.
6. Re:Not impressive by hedwards · 2011-11-13 08:59 · Score: 3, Informative
  
  GPS containing units had better be able to do that or they'd never get your location down to something reasonable.
7. Re:Not impressive by Hartree · 2011-11-13 09:09 · Score: 5, Interesting
  
  Mark Tilden tells a similar story about a prototype floor cleaning robot.
  It took some effort to find out why it worked when he watched it, but when he came home after being away, it was always sitting still in the middle of the room without having cleaned most of the room.
  The culprit: His cat would repeatedly trigger its collision avoidance sensor to make it turn away. It was a fun cat toy.
  It's hard to design against active maliciousness. :)
8. Re:Not impressive by Anonymous Coward · 2011-11-13 09:10 · Score: 2, Insightful
  
  Yes, but for example the iPod touch (for which this software is supposed to work) is not a GPS enabled device. But there is no need for clock synchronization anyway, the way they use their two devices. Since the second device replies after a certain delay, the first device just has to take into account that the time difference between signal and reply is twice the travel time plus the delay (and then correct for the offset introduce by microphone and speakers not being at the same place... :) ).
9. Re:Not impressive by Anonymous Coward · 2011-11-13 09:19 · Score: 4, Informative
  
  You just say "I started transmitting at x and you received it at y. x-y/speed of sound at sea level = your result.
  And then "your result" has at minimum a wavelength or two of precision, which sucks mightily at audio frequencies. This is why they use a nonperiodic (in this case chirped) waveform and correlation instead of "I started transmitting". You could have read this, at least, before making an ass of yourself.
  Not that it's so novel as they try to make it sound, either -- SONAR and RADAR guys did all that long ago, and you'd get the basics needed to implement it in your first semester of DSP in any EE program. In fact, if they're even doing "semiautomatic frequency calibration", they're obviously using linear chirps -- exponential chirps are relatively immune to Doppler or other frequency shifts, and since there's no analog design, are no harder to implement -- suggesting they haven't had (or slept through) any formal education in the field.
  It just bugs me when people who know even less run down every decent, if not outstanding, project like this with their own mix of even lamer approaches ("just as good!") and pie-in-the-sky fantasy ("then I'll get excited")
10. Re:Not impressive by hedwards · 2011-11-13 09:22 · Score: 1
  
  Good point, the summary said iOS so I was thinking iPhone.
11. Re:Not impressive by Anonymous Coward · 2011-11-13 09:30 · Score: 4, Interesting
  
  That sounds pretty awesome. Do you know if anyone from the biology department at MIT went back there to study that behavior? Since dolphins already use echolocation to navigate, I just wonder if they were doing more than amusing themselves, and actually managed to adapt to use the beacon system for their navigation. I'm not a biologist, and don't know much about dolphins, so I don't know if that's feasible or not, but it would be pretty amazing.
12. Re:Not impressive by poena.dare · 2011-11-13 09:33 · Score: 2
  
  Check out these pix... incredibly impressive (or not?)
  Acoustic Location and Sound Mirrors: http://www.aqpl43.dsl.pipex.com/MUSEUM/COMMS/ear/ear.htm
  bwahahaha
  today we can do it with iPads!
13. Re:Not impressive by Nerdfest · 2011-11-13 09:42 · Score: 2, Funny
  
  Sometimes dolphins can be real assholes.
14. Re:Not impressive by n01 · 2011-11-13 09:53 · Score: 2
  
  Please watch the second video, it shows how the app can be used with just one iOS device and headphones.
  
  I agree that by having the clocks exactly synchronized this could be a lot easier. (But even 1 ms of deviation means an uncertainty of around 34cm.) The challenge was to do it without having the devices synced by an external source (it works on iPod touch devices and iPad as well) and without using a communication channel other than sound.
15. Re:Not impressive by fragfoo · 2011-11-13 10:04 · Score: 2
  
  I'm curious, how did you figured out it was the dolphins fault? You found interactions in sound recordings?
  
  --
  Sig? Heil
16. Re:Not impressive by Anonymous Coward · 2011-11-13 11:06 · Score: 1, Funny
  
  No, those are blowholes.
17. Re:Not impressive by Kazymyr · 2011-11-13 11:41 · Score: 2
  
  I have used a program that did exactly that on my WinCE PDA, over 6-7 years ago.
  
  --
  I hadn't known there were so many idiots in the world until I started using the Internet -Stanislaw Lem
18. Re:Not impressive by Anonymous Coward · 2011-11-13 11:43 · Score: 0
  
  I suspect the culprit dolphins were young males who thought it was great that every time they farted they got an acoustic response from your beacons.
19. Re:Not impressive by CubicleView · 2011-11-13 12:31 · Score: 1
  
  Seems impressive enough to me, maybe a bit useless though. Thinking of alternatives, it might be possible to do it with image recognition as well. Judge the distance by the size of the target iphone or whatever.
20. Re:Not impressive by Anonymous Coward · 2011-11-13 13:15 · Score: 0
  
  Sometimes? Dolphins are generally assholes.
21. Re:Not impressive by DriedClexler · 2011-11-13 15:14 · Score: 1, Interesting
  
  They didn't, because the story is bullshit.
  
  --
  Information theory is life. The rest is just the KL divergence.
22. Re:Not impressive by Anonymous Coward · 2011-11-13 15:34 · Score: 0
  
  First thing I thought when I read about the app.
  Was the program called SonarCE per chance?
23. Re:Not impressive by milkmage · 2011-11-13 15:54 · Score: 1
  
  well.. it's not doppler but Batman isn't real anyway:
  Single device (headphone) mode:
  This mode works on the iPhone 3GS (and newer), iPod touch 3rd Generation (and newer) and on all iPads. You either need one of those devices and headphones with a mic or headphones without a mic and a iOS device with a built-in mic (excluding the iPod touch 3rd Generation). The resolution in this mode is 1mm or 1/10 of an inch, depending on the unit system you have selected.
24. Re:Not impressive by raddan · 2011-11-13 17:08 · Score: 1
  
  I suppose we should add "messing with my sonar buoys" to the list.
25. Re:Not impressive by cheeks5965 · 2011-11-13 18:10 · Score: 1
  
  oh that;s cool. X has been done, so it was easy. show me X^10!!! I might get off the couch for that!!! you know, some people actually work hard to improve the world, rather than sitting back and judging while not contributing. OOOH BURRN!!!!
  
  --
  -- Flame me and I will happily flame you back. Bring it!
26. Re:Not impressive by Anonymous Coward · 2011-11-14 00:54 · Score: 0
  
  > His cat would repeatedly trigger its collision avoidance sensor to make it turn away.
  LOL
  Or... his stupid cat would repeatedly get in the way ;)
27. Re:Not impressive by sifi · 2011-11-14 00:56 · Score: 1
  
  Thank-you for this - it made my day!
  
  Please can we ban radar and bring them back immediately.
  
  --
  Sig (appended to the end of comments you post, 120 chars)
28. Re:Not impressive by tehcyder · 2011-11-14 03:33 · Score: 1
  
  That sounds pretty awesome. Do you know if anyone from the biology department at MIT went back there to study that behavior? Since dolphins already use echolocation to navigate, I just wonder if they were doing more than amusing themselves, and actually managed to adapt to use the beacon system for their navigation. I'm not a biologist, and don't know much about dolphins, so I don't know if that's feasible or not, but it would be pretty amazing.
  Unfortunately, when they went back the dolphins had all been executed by Navy SEALS for reasons of national security.
  
  --
  To have a right to do a thing is not at all the same as to be right in doing it
29. Re:Not impressive by Anonymous Coward · 2011-11-14 04:01 · Score: 0
  
  Grandpa, what is a PDA?
30. Re:Not impressive by torgis · 2011-11-14 05:42 · Score: 1
  
  Another very good reason to punch a dolphin in the mouth.
31. Re:Not impressive by torgis · 2011-11-14 05:50 · Score: 1
  
  Even using the system clock with millisecond-level accuracy, you can still get accuracy down to within .343 meters, which is 1.13 feet. Assuming the speed of sound in dry air at 20C and 1 atmosphere pressure (thanks Wolfram!) is ~343.2 m/s, that's not bad at all.
32. Re:Not impressive by Unequivocal · 2011-11-14 07:09 · Score: 1
  
  How do you know that? Serious question -- b/c the story is a good one and if it's BS I'd like to know.
33. Re:Not impressive by DriedClexler · 2011-11-14 07:26 · Score: 1
  
  Burden of proof. If this were real, we would have links now. In the absence of evidence, we side with "don't believe the dubious claim". That's why I'm not asking you how you know there's not a monster under my bed, because if the monster is BS, "I'd like to know".
  
  --
  Information theory is life. The rest is just the KL divergence.
34. Re:Not impressive by SmurfButcher+Bob · 2011-11-14 08:49 · Score: 1
  
  That would be one of them, yes.
  Still have it, in fact!
  
  --
  
  help me i've cloned myself and can't remember which one I am
35. Re:Not impressive by Unequivocal · 2011-11-14 11:33 · Score: 1
  
  Thanks. Here is just a request from one of the teaming masses - I'd have preferred if you had said "this story is probably BS." Saying it's BS makes it sound like you have some fact or evidence that falsifies the claim, like a snopes report or personal knowledge. I wouldn't compare his story to monsters under the bed, but I do agree it has some traits in common with an urban legend.
36. Re:Not impressive by DriedClexler · 2011-11-14 12:45 · Score: 1
  
  Oh. Good point, I gave the wrong impression about what I knew. Sorry.
  
  --
  Information theory is life. The rest is just the KL divergence.
wait, dual-device mode? by Tyrannosaur · 2011-11-13 08:12 · Score: 4, Insightful

I thought this was going to be a cool sonar thing- you'll need 2 iphones? get a tape measure...
1. Re:wait, dual-device mode? by polymeris · 2011-11-13 08:25 · Score: 1
  
  I thought so, too.
  The sonar thing sounds difficult. Less cool, but potentially easier: use the camera's autofocus. How accurate could that be?
2. Re:wait, dual-device mode? by catmistake · 2011-11-13 09:43 · Score: 2
  
  how is this news? what I don't get... there have been acoustic tape measure apps on AppStore for a couple years now (just search AppStore for tape measure).... and none of them require more than one phone. I have expect to see a slashdot summary soon announcing the new development of the combustion engine.
  
  --
  The Admin and the Engineer
3. Re:wait, dual-device mode? by n01 · 2011-11-13 10:01 · Score: 5, Informative
  
  You can also use the device in a single device mode (with headphones), as shown in the second video. I just thought that the dual device mode would be more interesting and therefore emphasized it in my submission.
4. Re:wait, dual-device mode? by LWATCDR · 2011-11-14 02:37 · Score: 1
  
  This could be really useful for navigation inside a building. You could position transponders like this in say a mall or warehouse store and integrate it into a app.
  Need to find the nearest restroom? Need to find Bed Bath and Beyond.
  Where can I buy spray paint? It would have to use sounds outside of human hearing to not drive people nuts but it could be very cool.
  
  --
  See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
5. Re:wait, dual-device mode? by zevans · 2011-11-14 02:43 · Score: 1
  
  The autofocus in {smartphone} doesn't measure distance. It does it heuristically using sharpness of image. When you touch an off-centre subject on the screen of an iPhone you are telling it "make this bit of the image sharper than any other part" and it figures out the "best" way to do that. It has no clue whether that's 1 foot away or whether it's the moon.
  
  --
  "... and more and more now there are all kinds of electronic goodies available" -- Pink Floyd 1972
Star Trek? by Anonymous Coward · 2011-11-13 08:15 · Score: 5, Funny

Weapons Officer: "Captain I can't get a fix on the enemies position."
Science Officer: "We could try using an optimum-autocorrelation-signal and semi-automatic frequency calibration together with an averaging over multiple cycles."
Captain: "Good idea."
Me at home: "Who makes up this stuff."
1. Re:Star Trek? by Skapare · 2011-11-13 08:48 · Score: 1
  
  They didn't train the weapons officer to know to do this, yet he could just do it from those words?
  
  --
  now we need to go OSS in diesel cars
2. Re:Star Trek? by cgenman · 2011-11-13 15:33 · Score: 2
  
  Weapons Officer: "Captain I can't get a fix on the enemies position."
  Science Officer: "We could try using an optimum-autocorrelation-signal and semi-automatic frequency calibration together with an averaging over multiple cycles."
  Weapons Officer: "You mean, use the auto-shootey?"
  Science Officer: "Use the auto-shootey."
  
  --
  The ______ Agenda
How about an echolocation app :) by TheLink · 2011-11-13 08:15 · Score: 4, Interesting

Some humans can learn echo location[1], but just wondering if we could have an app that sends clicks and chirps and processes the echos and creates a picture or 3D model.
But it might need two or more "ears" to quickly build a 3D image of the environment.
[1] http://www.youtube.com/watch?v=qLziFMF4DHA
http://www.youtube.com/watch?v=GYWpxmcHTOc
--
- Too many replies beneath your current threshold
1. Re:How about an echolocation app :) by tokul · 2011-11-13 08:56 · Score: 2
  
  if we could have an app that sends clicks and chirps and processes the echos and creates a picture or 3D model.
  
  I am not sound technician, but such app won't see the difference between open space and sound absorbing surface. Picasso might draw better 3d model than echo app given that different materials have different sound absorbing characteristics.
2. Re:How about an echolocation app :) by Timmmm · 2011-11-13 12:22 · Score: 1
  
  Yeah it's impossible with one microphone/speaker. Sorry batman.
  I suppose in theory (read: it will never work) you could do it if you have lots of phones in an area. And you beefed up the phone speakers a lot.
3. Re:How about an echolocation app :) by Anonymous Coward · 2011-11-13 12:36 · Score: 0
  
  Some humans can learn echo location
  Correction - most humans can learn to do this. It takes about 5 days with 4 sessions a day of 15 minutes to learn the basics of how to listen to objects in your local environment. Takes about 10 minutes to prove it to yourself in an large open space.
  
  , but just wondering if we could have an app that sends clicks and chirps and processes the echos and creates a picture or 3D model.
  But it might need two or more "ears" to quickly build a 3D image of the environment.
  With humans - we just move our heads. Make tsck sound, listen, move head, repeat. I learnt the tsck technique, but I'm told clicking is more reliable.
  link
4. Re:How about an echolocation app :) by tomhudson · 2011-11-13 12:48 · Score: 1
  
  With humans - we just move our heads. Make tsck sound, listen, move head, repeat. I learnt the tsck technique, but I'm told clicking is more reliable.
  
  So the real story is that Africans have been doing echo-location for generations, and that's why their names have click sounds in them! "Where is Mb*click*saba? - Oh, I hear where you are!"
5. Re:How about an echolocation app :) by cgenman · 2011-11-13 15:40 · Score: 1
  
  The iPhone does have 3 speakers and 2 microphones. Most aren't particularly good ones, mind you, and individual addressability is a problem. It's really not practical. Add in a gps and camera, and it's not quite as bad as you make it out to be.
  Of course, using a camera properly would be cheating. But I'm a bit surprised nobody has done it on the iPhone.
  
  --
  The ______ Agenda
6. Re:How about an echolocation app :) by T-Bone-T · 2011-11-13 16:03 · Score: 1
  
  As an iPhone owner, I'm curious how you claim it has 3 speakers and two microphones. Did you mean 2 speakers and 1 microphone? I see an earpiece speaker and a bottom speaker with a microphone on the other side of the dock connector.
7. Re:How about an echolocation app :) by Anonymous Coward · 2011-11-13 17:31 · Score: 0
  
  It's quite possible. It's known as synthetic aperture radar. You have one antenna, but you move it around.
8. Re:How about an echolocation app :) by ceoyoyo · 2011-11-13 17:32 · Score: 1
  
  It's got an earpiece speaker, a bottom speaker (maybe the OP thought it was stereo, meaning two bottom speakers), the regular speaking mic and a noise cancellation mic. So two speakers and two microphones.
9. Re:How about an echolocation app :) by T-Bone-T · 2011-11-14 01:10 · Score: 1
  
  Thanks for clearing that up.
10. Re:How about an echolocation app :) by Commontwist · 2011-11-14 11:43 · Score: 1
  
  Maybe could use a single iPhone if you could combine all the data from audio input/output, GPS, and the visual camera data. Dunno how much number crunching that would need though.
This is news because it's on iOS, right? by QuasiSteve · 2011-11-13 08:18 · Score: 5, Funny

Because such an app already existed for PocketPC (That'd be Windows Mobile):
http://nerdipedia.com/tiki-index.php?page=Sonar+CE
Oh, and desktop PC:
http://nerdipedia.com/tiki-index.php?page=Sonar&structure=index
I hear there's a flashlight app for iDevices, too - Slashdot should really look into that. It's magical.
1. Re:This is news because it's on iOS, right? by spire3661 · 2011-11-13 08:38 · Score: 2
  
  What I want to know is why do i need a 3rd party app to turn on the flash emitter? This is Doom 3 levels of stupidity regarding the utility of a light source.
  
  --
  Good-bye
2. Re:This is news because it's on iOS, right? by wahaa · 2011-11-13 09:07 · Score: 2
  
  And for Android:
  https://market.android.com/details?id=com.dicon.sonar&hl=en
3. Re:This is news because it's on iOS, right? by QuasiSteve · 2011-11-13 10:27 · Score: 2
  
  What I want to know is why do i need a 3rd party app to turn on the flash emitter? This is Doom 3 levels of stupidity regarding the utility of a light source.
  You know, that's a good question. However, the answer has to be a bit three-fold.
  People have been using cellphones as makeshift flashlights pretty much since the first cellphones with a reasonably bright white screen came onto the market.. and why not, the screen was bright enough to navigate indoors, bright enough for the whole "finding the lock of your door" (because I guess some people don't just learn where it is after living somewhere for ages), etc.
  So whenever you needed a 'flashlight' in those times, just press any random button on your phone and you have your light - so you didn't need an app and you had a button to turn it on.. even though it was a side-effect.
  Then came the phones that had a small light bulb or LED that acted as a camera flash - they would often be used for illumination as well to aid in focusing. This means that on those phones, you would have a rather brighter light source than the screen if you could just get that light to turn on. Thankfully, for most phones, that just meant pressing the camera button. Yes, the camera 'app' would launch, but at least there was your light.
  On most Windows Mobile devices there were APIs to turn on the emitter or your app could just fake being the camera app without actually doing anything with the camera - and your app could be bound to a button and on the light would go.. another press and you could turn it off again. But you didn't really need this app.
  Then come the newer generation of phones, however. I'm going to assume it at least still has a dedicated camera button - but if it's an Android, that might mean you can't just press it.. you have to long press it. Next, the emitter isn't just always on anymore.. half-press starts illumination, until focus is acquired or couldn't be acquired, and it turns off again.
  So at this point, your makeshift flashlight-by-using-camera function has already been crippled. If you want a more continuous light source (aside from the screen, and the trend is dark backgrounds and displays become ever darker in the blacks, so that may not be a good option anymore) you'll have to grab one of the apps. If you're lucky, you can at least bind that to a button. In Windows Mobile that was something that was built-in.. bind any button to any app. On Android, at least? Not so much. You'll need another set of apps to do that.
  Now fast forward again and we're doing away with not just as many physical buttons as possible, but even the virtual buttons.. and remapping them is a no-no. Device makers are saying that buttons is far too confusing, too much freedom, too much power. Less buttons is more. So now you can't even bind an app to a button anymore, and for your makeshift flashlight to work, you'll have to just start up the flashlight app.
  Thankfully, you can at least still put that on the 'home' screen. Not that doing so is very useful when your device is locked.. you'll first have to slide a button to unlock it, or input a code/pattern/phrase/mugshot/fingerprint... at least until somebody makes a custom lock screen that has a flashlight option - if custom lock screens remain allowed, that is.
  But that's only part of your question... why do we need apps: because built-in functionality no longer caters to the need.
  The other part should be obvious.. why DOESN'T the built-in functionality cater to that need?
  Well, again, manufacturers are doing away with the buttons.. which means that whatever thing is going to turn on the emitter is going to be an 'app' anyway. A button would be infinitely more useful.. a button that would work even if the device were locked would be grand. But alas, it's a button and manufacturers are convinced buttons are evil.
  So why doesn't a 'flashlight' app at least ship with most devices? That's one I don't have any plausible answer to. I
4. Re:This is news because it's on iOS, right? by BarryJacobsen · 2011-11-13 12:04 · Score: 1
  
  Or you could use the built in camera app and turn on the flash...
  
  --
  Track your TV Shows with your iPhone - FREE
5. Re:This is news because it's on iOS, right? by tomhudson · 2011-11-13 12:52 · Score: 1
  
  Wouldn't it be smarter to, for the same $0.99, buy a combo laser pointer/led light keychain thingee, complete with batteries? You can also use it to tease the dogs and cats and enrage skunks (yes, skunks get REALLY mad when you try to tease them with a laser pointer, and will charge if you're not careful ... been there done that, left the vicinity asap while there was still a fence between us).
6. Re:This is news because it's on iOS, right? by QuasiSteve · 2011-11-13 13:50 · Score: 1
  
  That depends on one's definition of 'smarter', of course.
  Is it a better light source and comes with additional perks (such as the laser pointer, maybe a UV-B emitter, too)? Yes.
  On the other hand.. it's an additional thing to carry. In combination with your keys, that might not seem so bad. On the other hand, the keys are prone to scratch them up. But there are models that have the emitters recessed within the body so that, even if aesthetically it ends up shredded, at least your beam would be fine.
  That does leave the batteries, however... most of the keychain ones run on an AAA-battery at best, but usually coin cells.. although those do come in rechargeable form, you'll have to get a charger for them, first.
  Compare this again to the cellphone which most people carry even when they don't carry their keys (because somebody else is at home to let them in, say... but being able to call said somebody else in case you get stuck somewhere is rather useful), is thus not an additional item for most people, and recharges easily off the included recharger, re-used recharger or practically any USB connection (as long as there's a micro/mini tip, as applicable).
  Perhaps flipping the question around would be interesting... why not add a laser pointer to the cell phone? And I say: indeed, why not? That could open up a whole host of 'new' apps ( that is to say, apps that replicate pre-existing laser-dependent applications ).
7. Re:This is news because it's on iOS, right? by Anonymous Coward · 2011-11-13 17:20 · Score: 0
  
  The massively small install base of Pocket PC, along with the fact that finding and installing compatible software was a daylong task thanks to no functional app store means that demonstrating this app working on two devices anywhere other than a microsoft campus building would have been about as statistically possible as being struck by lightning.
  So, yeah, this is news because there is a very good chance I could see it work.
  Your high-horse is waiting.
8. Re:This is news because it's on iOS, right? by Anonymous Coward · 2011-11-13 19:33 · Score: 0
  
  Troll, Windows CE is everywhere, in GPSs, some projectors, a whole bunch of older phones and it was easy to install stuff, you did not even have to ask Apple for permission.
9. Re:This is news because it's on iOS, right? by tomhudson · 2011-11-14 03:27 · Score: 1
  
  Please re-read what I wrote. You don't need a battery charger - $0.99 includes the batteries - 3 coin cells.
  The emitters are recessed 1mm.
  Nobody's going to worry about keys scratching the aluminium surface of a 99-cent pointer.
  Now please consider a real-life scenario - you have the light on your key-chain, so you don't have to fumble around looking for both your keys AND your light. And if you drop it in the dark, you won't break anything.
  Winter is coming - it's a lot easier to drop a phone while wearing gloves.
10. Re:This is news because it's on iOS, right? by Doc+Ruby · 2011-11-14 04:57 · Score: 1
  
  Is there an Android app (or, preferably, library) that can use the sonar to sense the size and rough shape of a whole room, making a 3D model? Maybe by correlating distance pings with the accelerometer (and GPS for added position context) while waving the device around.
  
  --
  --
  make install -not war
11. Re:This is news because it's on iOS, right? by tlhIngan · 2011-11-14 05:20 · Score: 1
  
  What I want to know is why do i need a 3rd party app to turn on the flash emitter? This is Doom 3 levels of stupidity regarding the utility of a light source.
  You can turn on the flash without a third party app.
  Camera App, click the thunderbolt and select "On". It defaults ot Auto, but you can have it forced on and off as well.
  Third party apps make it a little easier though - some do nothing but turn it on at launch and turn it iff when you hit the home button.
  It's for potentially improving photos, not as a general purpose flashlight. Which is why it eats a ton of battery and can get dimmer as the protection circuits kick in to prevent it from overheating.
12. Re:This is news because it's on iOS, right? by QuasiSteve · 2011-11-14 10:50 · Score: 1
  
  Please re-read what I wrote. You don't need a battery charger - $0.99 includes the batteries - 3 coin cells.
  
  Which tend not to last very long. Yes, you can just buy new ones (or at $0.99 just buy a new keychain light). Not very environmentally awesome, but I realize some people find that rather shrugworthy anyway.
  Anyway, this is getting further and further from the discussion of why one needs flashlight apps on phones and the use of a phone as a flashlight in the first place.
  Best option? Get that $0.99 keychain flashlight and if it craps out, at least you've still got your phone. With a flashlight app.
Just use a damn tape measure! by Anonymous Coward · 2011-11-13 08:21 · Score: 0, Informative

Fuck, it's even easier just to use a damn tape measure. You don't have to synchronize them or any of this bullshit. Not only is a tape measure easier, but it's a fuck of a lot cheaper, too. Now you don't have to drop at least $1000 on some Apple devices.
It's one thing to use technology when it simplifies some existing task or job, but it's just fucking stupid when you use technology that only makes a simple task even more awkward, difficult and expensive.
1. Re:Just use a damn tape measure! by hdd · 2011-11-13 09:02 · Score: 2
  
  "Please note that while the resolution of the measurements may be as low as 1mm, the precision usually is not. While I have taken great care to make the app as reliable as possible, there are simply too many factors affecting the measurement process and the precision. That is why I want to be clear about one thing: there is absolutely no warranty that the measurements taken with Acoustic Ruler Pro are correct"
  Another good example of incorrect usage of the word precision. In this case, the method is actually quite precious, as in measurements are very repeatable. What the author meant is that the accuracy is not very good. I tried out the app just now, at the range of 22 inch (width of my monitor), it under estimates the distance by 1 inch; and for something half an inch apart, it over estimates by over an inch. It is possible to measure the non-linearity using a control setup, but the result would be largely useless, as measurement of different items requires placing the item near the source and receiver, and this will likely change the acoustic behavior of the environment and affect measurement accuracy.
  
  --
  This Sig is removed due to factual inaccuracy
2. Re:Just use a damn tape measure! by Anonymous Coward · 2011-11-13 09:43 · Score: 0
  
  If you must go high-tech get one of there:
  http://www.boschtools.com/Products/Tools/Pages/BoschProductDetail.aspx?pid=GLR225
  Cheaper and more accurate then a pair of ipods.
3. Re:Just use a damn tape measure! by n01 · 2011-11-13 09:57 · Score: 1
  
  Nobody in their right mind would buy two iOS devices just to use this app. But somebody who's got two of them already might consider buying this app for under a dollar. (Just one purchase required if you have both devices on the same iTunes account.)
4. Re:Just use a damn tape measure! by n01 · 2011-11-13 09:58 · Score: 1
  
  Thanks for clearing this up! I will use the word accuracy in the next update!
5. Re:Just use a damn tape measure! by DrgnDancer · 2011-11-13 10:01 · Score: 4, Insightful
  
  One suspects that the primary use case for this application is not, "Hey, we need to measure this, let's go get two iPhones!" It's "Hey we need to measure this and happen to have two iPhones, but no tape measure." Most people carry their phones around with them all the time, but unless they're contractors don't carry tape measures. The point of near ubiquitous mobile computers is that you can use them for lots of things. This is a cute and clever thing that you can now use them for.
  
  --
  I don't need a million points of light, just two points of multi-mode fiber and a 10 Gig-E router.
6. Re:Just use a damn tape measure! by artor3 · 2011-11-13 11:52 · Score: 2, Interesting
  
  No, the primary use case is "oh, this is nifty, let me play with it". The accuracy is nowhere near good enough for any measurement that actually matters.
7. Re:Just use a damn tape measure! by abigor · 2011-11-13 12:12 · Score: 1
  
  Except for all those MB Airs I saw up at Google the other day. Yep, those Google programmers sure don't like numbers. Right?
8. Re:Just use a damn tape measure! by Ol+Olsoc · 2011-11-13 14:17 · Score: 2
  
  Tape measure? Where do I get that app?
  
  --
  The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.
9. Re:Just use a damn tape measure! by BitZtream · 2011-11-13 16:08 · Score: 3, Insightful
  
  You could measure room wall lengths close enough for basic estimates on how much paint to buy or fence length estimates and such where you don't need cut to fit accuracy.
  
  --
  Persistent Volume manager for Kubernetes - https://github.com/dwimsey/openshift-pvmanager
10. Re:Just use a damn tape measure! by ynp7 · 2011-11-13 16:45 · Score: 0
  
  There's a flaw in your analysis. How is Apple supposed to sell anything if people stopped buying technology that makes simple tasks more awkward, difficult, and expensive? Think of Steve Jobs's poor, starving children!
11. Re:Just use a damn tape measure! by Meski · 2011-11-13 17:14 · Score: 1
  
  No, the tricorder app is cute and clever, and measures a lot more things. Useful? That's debatable.
12. Re:Just use a damn tape measure! by tftp · 2011-11-13 17:17 · Score: 1
  
  but unless they're contractors don't carry tape measures
  And unless they are contractors they don't need to measure anything. Do you recall an event in your life when you, completely out of the blue, needed to measure something like that? I can only think of the hardware store like Home Depot, but measuring tape is readily available there.
13. Re:Just use a damn tape measure! by Spacezilla · 2011-11-13 19:37 · Score: 1
  
  I tried out the app just now, at the range of 22 inch (width of my monitor)
  I'm 99.6% sure you got it right, considering this is slashdot and all, but you're sure your monitor is 22" wide, aren't you?
  (Just checking in case you're thinking you have a 22" monitor, so it must be 22" wide. Unlikely all things considered, but I still have to ask.) :)
14. Re:Just use a damn tape measure! by icebraining · 2011-11-14 01:17 · Score: 0
  
  Do you recall an event in your life when you, completely out of the blue, needed to measure something like that?
  Yes.
  
  --
  Dilbert RSS feed
15. Re:Just use a damn tape measure! by zevans · 2011-11-14 02:28 · Score: 1
  
  It's good enough for photography. It's good enough for buying carpet, tiles, or paint.
  
  --
  "... and more and more now there are all kinds of electronic goodies available" -- Pink Floyd 1972
16. Re:Just use a damn tape measure! by tehcyder · 2011-11-14 03:24 · Score: 1
  
  Fuck, it's even easier just to use a damn tape measure. You don't have to synchronize them or any of this bullshit. Not only is a tape measure easier, but it's a fuck of a lot cheaper, too. Now you don't have to drop at least $1000 on some Apple devices.
  That would be a valid comment if anyone actually bought an iPhone for use exclusively as a tape measure.
  
  --
  To have a right to do a thing is not at all the same as to be right in doing it
17. Re:Just use a damn tape measure! by tehcyder · 2011-11-14 03:43 · Score: 0
  
  Except for all those MB Airs I saw up at Google the other day. Yep, those Google programmers sure don't like numbers. Right?
  No one is saying that ALL Apple users are illiterate, innumerate, rich, gullible fashion victims.
  
  Just the vast majority.
  
  --
  To have a right to do a thing is not at all the same as to be right in doing it
18. Re:Just use a damn tape measure! by GrumpySteen · 2011-11-14 04:04 · Score: 2
  
  You can get enough accuracy for buying paint and fence length by counting your steps.
  You have to walk from one end of the measurement to the other whether you're counting steps or just putting the phones in place, but you don't have to walk back to the starting point to pick up a phone, however, so the entire process is easier and faster if you just count steps.
19. Re:Just use a damn tape measure! by GrumpySteen · 2011-11-14 04:11 · Score: 2
  
  The prostitute that laughed at you and said "that's not even four inches" doesn't count.
The Ping comes into the real world! by Commontwist · 2011-11-13 08:34 · Score: 1

Skynet: coming soon to an iPhone near you.
1. Re:The Ping comes into the real world! by Doc+Ruby · 2011-11-14 04:58 · Score: 1
  
  Can you believe that TCP/IP ping was named after the real world sonar ping that these apps are bringing to phones? Reality is so impressive when you use your brain.
  
  --
  --
  make install -not war
2. Re:The Ping comes into the real world! by Commontwist · 2011-11-14 11:27 · Score: 1
  
  Reality is even better with people who have a sense of humor.
  If you want to get ping picky one could say that 'named' is not the same as 'function'. TCP/IP pings are indeed technically different than sonar pings due to measuring time between terminals back and forth. Sonar measures distances by means of audio reflection alone (one source and one receiver) whereas this method is more in tune with TCP/IP measuring because it requires two terminals sending signals back and forth to measure distance.
2009 : Sonar Ruler by sugarmotor · 2011-11-13 08:35 · Score: 5, Insightful

This didn't seem to do that good of a job, but was 2 years ago.
* Sonar Ruler, By Laan Labs: http://itunes.apple.com/app/sonar-ruler/id324621243?mt=8
* http://thenextweb.com/2009/08/20/amazing-iphone-app-lets-measure-distance-echoes-works/
Happy measuring!

--
http://stephan.sugarmotor.org
1. Re:2009 : Sonar Ruler by Anonymous Coward · 2011-11-13 14:27 · Score: 0
  
  Not compatible with iPod touch. Wasted $1. Jerks.
My $0.99 by Anonymous Coward · 2011-11-13 08:41 · Score: 0

This article is an ad, and nothing more, for a $0.99 app download. This isn't revolutionary, it isn't even all that neat, since it has been done for years, silently, on automobiles. If carmakers can figure it out, the technology is probably pretty mature.
1. Re:My $0.99 by Skapare · 2011-11-13 08:50 · Score: 0
  
  So where's the Android app to do this? Oh wait, it would probably spam everyone in the room, first.
  
  --
  now we need to go OSS in diesel cars
Accessibility by Anonymous Coward · 2011-11-13 09:01 · Score: 0

I wonder if this could be coupled with Siri to give blind people info about their surroundings.
1. Re:Accessibility by Anonymous Coward · 2011-11-13 09:35 · Score: 0
  
  Siri: Ooo look, there's another iPhone 7 meters north
"Novel"? Really? by pipedwho · 2011-11-13 09:04 · Score: 3

When I see the word 'novel' applied to techniques that have been used for decades, I smell 'patent lawyer'. And be extension: astroturf.
Signal processing techniques applied to sonar (whether active, passive or beaconed) including signal correlation, spectral adaptation/equalisation, and filtering are standard fare in this field.
Maybe by novel they mean "on an iPhone"?
That being said, there is nothing that says this won't work - as it worked extremely well 20 years ago on dedicated systems with far less processing power. (Those systems, however, used multiple arrayed transducers and tailored beam patterns to significantly reduce the effective noise floor.)
1. Re:"Novel"? Really? by Anonymous Coward · 2011-11-13 13:25 · Score: 0
  
  Maybe by novel they mean "on an iPhone"?
  Actually, yes. The theory might be the same, but making it work in practice with what a device gives you is something else.
  As someone who's been experimenting with doing the same thing, let me assure you it's really quite a bit more difficult to do this with the commodity speakers and microphones found in smart-phones. Because these are designed and optimized for music and speech, the dynamic response of the transducers and the signal processing in the audio firmware/hardware plays havoc with any frequencies that fall outside our perceptual range. Not only that, "standard" techniques often assume the presence of specialized hardware such as, as you mentioned, multiple, specially-crafted, properly-oriented transducers. Furthermore, multi-path can be a major problem for sonic ranging if you are in a small-ish or crowded room. Doing the same thing with the speakers/microphones of a smartphone, the placement and orientation of which you have no control over, is not the same thing at all.
  Might be surprising to you, but "techniques that have been used for decades" with specialized equipment don't transfer over as well to commodity equipment.
2. Re:"Novel"? Really? by pipedwho · 2011-11-13 15:27 · Score: 4, Informative
  
  Keep in mind that all that 'specialised equipment' evolved out of a need to improve the simpler predecessor systems.
  Sonar and sonic range finding systems use all that 'extra equipment' to achieve ranges far in excess of 25m and in mediums much more variable than air. The impulse response of miniature consumer grade condenser microphones and speakers are more than adequate for air use within an octave of the audible spectrum. The speakers in the iPhone are primarily limited by their output power, and the fairly omnidirectional nature of the microphones may lack overall sensitivity, but both are simple parameters that really only end up reducing total available range and accuracy (as compared to specialised custom hardware using the same algorithmic solutions).
  Applying the same design principles that would normally be applied to a specialised system design to an iPhone implementation, would be very unlikely to provide anything unknown to someone in the industry. This is very similar to early stage engineering "proofs of concept" that are used to test various parameters within a system design, without the interactive complexity of implementing the entire system.
  There is nothing within this extremely simple setup that hasn't been done as part of a larger system design. A single (consumer grade) speaker + microphone used in transmissive, active echo, or for passive echolocation is not unusual. Considering the iPhone has excessive processing capability to implement all the standard approaches (correlation, convolution, deconvolution, filtering, impulse response measurement, etc), there is no real need to be 'clever' as such.
  'Back in the day', when trying to do this with a 10MIPS DSP in real time with moving objects, it was much more important to come up with better algorithms and shortcuts. Of course, this could otherwise have easily been done with standard theoretical methods and a modern processor a hundred times more powerful.
  I see patents pop up all the time that describe things that are far from novel. Most of those patents are usually 'invented' by people with no real experience in the given fields. ie. Ideas that seem like earth shattering discoveries to the uninitiated, but are really just standard techniques used by properly skilled engineers.
  I'm not saying that this iPhone app is bad/good, just that it is VERY unlikely to contain any actual improvements to the current state of the art (or the state of the art 20 years ago for that matter). I say this, because there is no real need to do anything new to achieve the results that they are claiming.
  BTW, in the past I've worked on sonar/radar systems for air, ocean and rock. The biggest problem in 'noisy' environments is a lack of output level. Multipath isn't a major problem for a point to point (ie. line of sight, shortest path) ranging device - unless you're talking about wave guide shapes/sizes over long distances.
3. Re:"Novel"? Really? by Anonymous Coward · 2011-11-13 20:35 · Score: 0
  
  In my experience, the response of acoustic speakers is not that great for anything other than speech and music. If you have a smartphone, try generating a white noise signal and watch the spectrum of the audio input (there are audio spectrum analyzer apps around); it won't be anywhere near flat.
  On the other hand, my acoustic signal processing experience mainly has been with signals that were somewhat spread out (data communications), which is where the non-linear frequency response of audio I/O messed things up. The chirp signals these guys use probably occupy a much more linear part of the spectrum.
  
  I'm not saying that this iPhone app is bad/good, just that it is VERY unlikely to contain any actual improvements to the current state of the art (or the state of the art 20 years ago for that matter). I say this, because there is no real need to do anything new to achieve the results that they are claiming.
  Here's the part that I've found really problematic on iOS devices: audio processing latency. Most signal processing of the type you describe typically work with real-time systems which makes timing straightforward. But this is not so on iOS devices, even with their low-latency API... Worse than the latency, there is a fair bit of jitter. Sure, you can do real-time stuff at the driver-level, but an app in the app store does not get that level of control. I have some idea about how to account for it, but I'm not sure how these guys have done it (I'd guess the "multi-cycle" approach has something to do with it).
  
  I see patents pop up all the time that describe things that are far from novel. Most of those patents are usually 'invented' by people with no real experience in the given fields. ie. Ideas that seem like earth shattering discoveries to the uninitiated, but are really just standard techniques used by properly skilled engineers.
  Patents are a different matter. Sure, you'll find standard stuff described all over in the text of the patent, but what really matters are the claims. The rest of the patent is only to provide background information and detailed description of what the claims cover. Of course, often patents do slip through with claims covering existing stuff, but in my experience this is not as common as /. tends to think. In my experience, in the past few years, the various patent offices have become very good about finding relevant prior art.
4. Re:"Novel"? Really? by Doc+Ruby · 2011-11-14 04:59 · Score: 1
  
  Is there an Android app (or, preferably, a library) that can use the sonar to sense the size and rough shape of a whole room, making a 3D model? Maybe by correlating distance pings with the accelerometer (and GPS for added position context) while waving the device around.
  
  --
  --
  make install -not war
5. Re:"Novel"? Really? by pipedwho · 2011-11-14 15:36 · Score: 1
  
  In my experience, the response of acoustic speakers is not that great for anything other than speech and music. If you have a smartphone, try generating a white noise signal and watch the spectrum of the audio input (there are audio spectrum analyzer apps around); it won't be anywhere near flat.
  On the other hand, my acoustic signal processing experience mainly has been with signals that were somewhat spread out (data communications), which is where the non-linear frequency response of audio I/O messed things up. The chirp signals these guys use probably occupy a much more linear part of the spectrum.
  Unless the transducer has a significantly non-linear or narrow band response, it is extremely easy to compensate for this with only a minor signal to noise / distortion degradation. An impulse response and deconvolution is a good starting point when trying to subtract out the effects of imperfect devices (obviously within reason - you can't reverse the effects of a null or total signal cancellation, but a +/-10dB variation across the required spectrum wouldn't be too much to ask).
  
  Here's the part that I've found really problematic on iOS devices: audio processing latency. Most signal processing of the type you describe typically work with real-time systems which makes timing straightforward. But this is not so on iOS devices, even with their low-latency API... Worse than the latency, there is a fair bit of jitter. Sure, you can do real-time stuff at the driver-level, but an app in the app store does not get that level of control. I have some idea about how to account for it, but I'm not sure how these guys have done it (I'd guess the "multi-cycle" approach has something to do with it).
  In a system like this, the continuous streaming nature of the conversion process (crystal locked ADC/DAC sample clocks) acts as the synchroniser, and a 100ms (or even a few hundred milliseconds) latency isn't likely to cause a major problem (unless you have a huge number of feedback rounds between the two devices and expect instant results). Fractional sample rate conversion is useful for perfect synchronisation, but probably not necessary here. And jitter is only problematic if you're seriously underpowered (in which case you just increase the latency until all your processing can be completed before you are required to output a result based on that data), or you're trying to drive the sampling clock source from a recovered clock source (generally a bad idea and obviated by use of fractional sample rate conversion if required).
  
  Patents are a different matter. Sure, you'll find standard stuff described all over in the text of the patent, but what really matters are the claims. The rest of the patent is only to provide background information and detailed description of what the claims cover. Of course, often patents do slip through with claims covering existing stuff, but in my experience this is not as common as /. tends to think. In my experience, in the past few years, the various patent offices have become very good about finding relevant prior art.
  I have seen many times the 'standard stuff' claimed as the 'inventive step' underpinning the patent. Patents are hard to read at the best of times and I have mostly only ever reviewed them when requested to by a client that requires an interpretation of what is really being claimed. It doesn't take long to get pretty jaded when you've been doing that for a while. That being said, it's been a couple of years since I've done this, so maybe as you say things have improved. But, since this has been going on for over 20 years (and probably since the dawn of the patent system), I very much doubt it. Maybe they're rejecting more things that are obvious, but it really does take someone skilled in the field to be able to understand the problem and do this properly - including point out the prior art that may not use the same terminology as used in the patent. (eg.
Stand-alone by soundguy · 2011-11-13 09:14 · Score: 3, Insightful

About 20 years ago, I had a hand-held device roughly the size of a smart phone but twice as thick that did distance measuring all by itself. It was infrared and as I recall, it was something like $25.00 from Rat Shack or Home Depot or some place like that. A 30 foot tape measure is about $8.00 and works a lot better.

--
Nothing worthwhile ever happens before noon
1. Re:Stand-alone by Anonymous Coward · 2011-11-14 00:39 · Score: 0
  
  I saw that from a friend of mine. He worked on an architectural firm. Those folks use it all the time!
2. Re:Stand-alone by north.coaster · 2011-11-14 01:45 · Score: 1
  
  Polaroid was selling ultrasonic sensors and an experimenters kit that could be used for this purpose thirty years ago. While there are definitely applications where this type of technology is useful, I agree that a tape measure works great for most purposes.
3. Re:Stand-alone by Muad'Dave · 2011-11-14 02:03 · Score: 1
  
  Radio Shack has Parallax Ping Modules in stores around here. I was absolutely flabbergasted to see them after so many years of RS being useless for the experimenter.
  
  --
  Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
Overkill by History's+Coming+To · 2011-11-13 09:41 · Score: 1

Or you can use a piece of string, as long as it's no shorter than 25m.

--
Please consider this account deleted, I just can't be bothered with the spam anymore.
$1,200... by Anonymous Coward · 2011-11-13 10:46 · Score: 1

...seems a little expensive for a tape measure.
VERY VERY OLD NEWS by Anonymous Coward · 2011-11-13 10:51 · Score: 0

There have been apps that do this very same thing around on iphones for about 2 to 3 years now!!!! how the heck is this news???? its a blatant advertisement! I think im going to stop reading slashdot now... and stick with el reg...
Steam is responsible by nauseous · 2011-11-13 10:54 · Score: 0

Steam is responsible for this and should be accountable for any misuse of your personal information. I'm ready to go legal by punishing these companies for their security flaws and allowing our personal information to be breached. It's ridiculous! We need to stand up and go after all companies not keeping up-2-date on security for our personal data. They're responsible for keeping our data secure.
Gee! All you need is... by Telephone+Sanitizer · 2011-11-13 10:55 · Score: 0

Gee! All you need is a 25 meter headphone cord for this to work.
Everyone has that!
1. Re:Gee! All you need is... by n01 · 2011-11-13 20:34 · Score: 1
  
  Or two iOS devices...
Frequency? by wisebabo · 2011-11-13 11:08 · Score: 3, Interesting

Is there any benefit to moving to ultrasonic frequencies? Other than making it inaudible (so you don't bother people but maybe dogs!), would this improve the resolution? Does the range decrease? Do consumer level devices cover such a broad spectrum?
By the way, has anyone made an iOS or Android App that can record in the ultrasound (or infrasonic) ranges and change it so that we can listen in audible ranges? Might be neat to see/hear what the bats are doing!
Also, how DO bats build up a good 3D map of their surroundings using just one "speaker" and two "microphones"? Do they send out beams or are their ears swiveling? And, with the limited amount of computing power on a smartphone, would it be able to duplicate it? A bat's brain doesn't seem particularly large and they are doing this FAST (on the fly, ha ha).
1. Re:Frequency? by Anonymous Coward · 2011-11-13 15:13 · Score: 4, Insightful
  
  Is there any benefit to moving to ultrasonic frequencies? Other than making it inaudible (so you don't bother people but maybe dogs!), would this improve the resolution? Does the range decrease? Do consumer level devices cover such a broad spectrum?
  As I mentioned in another comment, I've been experimenting with a similar application on iOS devices. Yes, consumer devices do cover ultrasonic frequencies, but barely. For average humans, ultrasound begins above 18 - 19 KHz, and devices with 48KHz range can produce up to 24KHz frequencies... in theory. The problem is that the commodity speakers/microphones in smart-phones are optimized for the human perceptual range, and since ultrasound is beyond that, the transducer dynamic range and/or the in-built signal processing conspire to significantly attenuate and distort ultrasonic signals. Using an iPad, in preliminary experiments, I could only get a range of ~5m using ultrasound, whereas these guys say they can go up to 25m.
  Moving to ultrasound also can affect resolution negatively. Since you're effectively using a much smaller bandwidth signal, your positioning accuracy reduces, on top of which, multipath problems get much worse. (Smaller bandwidth because by limiting the signal to ultrasound, you only get a bandwidth between ~18KHz and 24KHz for a 48KHz sampling frequency, and the iPad microphone strongly attenuates signals after the 20KHz range.)
  
  Also, how DO bats build up a good 3D map of their surroundings using just one "speaker" and two "microphones"? Do they send out beams or are their ears swiveling? And, with the limited amount of computing power on a smartphone, would it be able to duplicate it? A bat's brain doesn't seem particularly large and they are doing this FAST (on the fly, ha ha).
  Bat ears are highly specialized. This link gives a brief overview of how bats do echo-location:
  http://science.howstuffworks.com/environmental/life/zoology/mammals/bat2.htm
  I believe smartphones have, or will soon have, enough processing power to do the necessary signal processing if we can design the right algorithms. The problem is it would also need highly specialized audio transducers to get any useful signals, which may not necessarily fit into a smartphone form factor.
2. Re:Frequency? by Anonymous Coward · 2011-11-13 16:21 · Score: 1
  
  Actually, scientists are still trying to figure out how bats can do what they do, as well as they do. Even the massive military and scientific radar sets have trouble matching the kind of sonar analysis that bats perform instantaneously. Dolphins can perform similar feats of acoustic wizardry, at levels that radar sets are just now able to begin emulating to any reasonable degree of comparison. Many advances in military target-tracking radars have been at least influenced by observing bats in chase of flying insects. Bats change their frequency, pulse repetition rate, and signal patterns in order to accurately determine the insect's location during final aquisition, even when surrounded by other actively echolocating bats of the same species.
  A single antenna (transmit and receive) (speaker and microphone) is sufficient when used along with short, time-encoded pulses and doppler processing to build up 3D environment maps, but noise levels will limit the accuracy of measurements performed using these methods.
  "Blip, Ping, and Buzz," [http://www.amazon.com/Blip-Ping-Buzz-Making-Sense/dp/0801886651] is an excellent book, of a moderate technical level, that describes the operation of modern pulse-compression synthetic-aperture radar and compares that to the processing methods that biologists and radar scientists have inferred that bats and dolphins must use in order to demonstrate their observed behavior.
  -Antenna/Electromagnetics/Radar graduate student
3. Re:Frequency? by Anonymous Coward · 2011-11-13 16:21 · Score: 0
  
  yes in fact higher frequency sound waves diffract less are far more directional than low frequencies. so you can point the phone in the direction of the distance you want to measure. a low frequency wave would go in all different directions, so its hard to point the phone in any particular direction and get that distance exactly.
  http://hyperphysics.phy-astr.gsu.edu/hbase/sound/diffrac.html
4. Re:Frequency? by Anonymous Coward · 2011-11-13 18:12 · Score: 0
  
  http://lmgtfy.com/?q=bat+detector
5. Re:Frequency? by sharpneli · 2011-11-13 20:45 · Score: 1
  
  I bet you can go to 25m too if you just average the signal enough (use multiple cycles). The chirp and averaging both are there just to increase the signal to noise ratio. I'd say the best way is just to use all the available bandwidth in the device (range resolution is determined by bandwidth), not limiting oneself to just audible or inaudible parts of the spectrum.
6. Re:Frequency? by Muad'Dave · 2011-11-14 02:06 · Score: 1
  
  Actually, scientists are still trying to figure out how bats can do what they do, as well as they do.
  Because the ones that can't "do what they do as well as they do" died off? :-)
  
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  Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
Laser for measuring distance? by Twinbee · 2011-11-13 12:33 · Score: 1

Can't a laser do this kind of job instead of sound?

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Why OpalCalc is the best Windows calc
1. Re:Laser for measuring distance? by Anonymous Coward · 2011-11-13 14:27 · Score: 0
  
  Yes. So hopefully iPhone 5 has a laser!
2. Re:Laser for measuring distance? by Anonymous Coward · 2011-11-13 17:14 · Score: 0
  
  Yeah, but could you do it with a SHARK??!!
3. Re:Laser for measuring distance? by treeves · 2011-11-14 07:44 · Score: 1
  
  Yes.
  
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  ...the future crusty old bastards are already drinking the Kool-Aid.
For God Sake by nedlohs · 2011-11-13 16:16 · Score: 1

At least say "I recently published an app for the iOS platform that" instead of "A recently published app for the iOS platform".
Pretending it's something interesting you just stumbled across is being deceptive.
For that matter by Sycraft-fu · 2011-11-13 18:48 · Score: 1

You can buy devices that do it standalone, with only one device. Home Depot sells them. They shine a laser for aiming and generate repeated clicks. They then listen for the reflection and give you a distance measurement using that. Works reasonably well. Have to use it in a somewhat quiet indoor space, and if you aim it at something that absorbs sound it doesn't work, but for all that it lets you get a quick and pretty accurate distance measurement for cheap.
There are more expensive ones that use laser pulses to do it all optically and are more accurate and work in more environments, however they do cost like 10x as much since it requires much more precision timing equipment to deal with things moving at light speed instead of the speed of sound.
Nothing special about this kind of technology.
1. Re:For that matter by Doctor+Memory · 2011-11-14 06:18 · Score: 1
  
  I had one of the standalone ones, it was basically useless for anything other than measuring your distance to a perpendicular, flat, hard surface that wasn't too far away. If you use one in a long narrow room the echoes interfere with the reflected signal, if you point it at a bookshelf or a framed picture without glass the signal gets attenuated too much, and forget about trying to measure the distance between a couple of curved columns. I bought one of the laser ones to replace it and yeah it was like 4x the price (~US$100), but the only problems I've had with it are when trying to use it to measure the distance to a window, and even then the beam's narrow enough I can usually find a point on the frame to use.
  
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  Just junk food for thought...
Active Sonar already did it by Anonymous Coward · 2011-11-14 00:08 · Score: 0

I got an app called Active Sonar that does just this when I first got my iPhone 2 or 3 years ago. It was created by an audio processing company as sort of a demo of their skills. The app shows dots in the vertical axis showing distances at which it gets returns, and each pulse gets a new horizontal row... the effect is that for instance if you're walking towards a wall you'll see a line getting lower over time, or if you're sitting still and a cat walks between you and the wall you'll have a straight line where the wall is and then a little line will appear and disappear lower down as the object moves between you and the wall. Pretty neat.
App did this 3 years ago. by Anonymous Coward · 2011-11-14 01:42 · Score: 0

Sonar Ruler did this 3 years ago.
Thanks for the comments! by wisebabo · 2011-11-14 01:53 · Score: 1

I (tried to) learn a lot from these postings (some of it was at the limit of my understanding though). I appreciate the information!
3D Space Modeler for Android? by Doc+Ruby · 2011-11-14 05:03 · Score: 1

Is there an Android app (or, preferably, library) that can use the sonar to sense the size and rough shape of a whole room, making a 3D model? Maybe by correlating distance pings with the accelerometer (and GPS for added position context) while waving the device around..

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make install -not war