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iOS App Acoustically Measures Distances Up To 25 Meters

samzenpus posted more than 2 years ago | from the new-tool-for-the-box dept.

Iphone 154

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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154 comments

Aliens (1)

ae1294 (1547521) | more than 2 years ago | (#38042816)

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...

Re:Aliens (0)

Anonymous Coward | more than 2 years ago | (#38043002)

The Aliens also need to have an app on their iOS too. What are the chances?

Re:Aliens (0)

Anonymous Coward | more than 2 years ago | (#38043014)

There's an app for that.

Nifty (1, Insightful)

Anonymous Coward | more than 2 years ago | (#38042822)

But still an advertisement.

Re:Nifty (5, Insightful)

bonch (38532) | more than 2 years ago | (#38043512)

So Slashdot can't report on anything, ever, if it's for sale somewhere. Got it.

Re:Nifty (-1)

Anonymous Coward | more than 2 years ago | (#38043550)

welcome to capitalism, fucktard. what progress did feudalism make again?

Re:Nifty (0)

Anonymous Coward | more than 2 years ago | (#38044276)

How about an app that can determine a girl's "true" cup size (minus the padding) from 25 meters? I'd get it.
roxy

Not impressive (4, Interesting)

girlintraining (1395911) | more than 2 years ago | (#38042828)

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.

Re:Not impressive (4, Informative)

grumbel (592662) | more than 2 years ago | (#38042876)

Yep, neat, but not exactly ground breaking. The OLPC had such an application for the last few years.

Re:Not impressive (2, Funny)

Anonymous Coward | more than 2 years ago | (#38042994)

No no no no no. Apple first. Apple first. [rocks back and forth]

Re:Not impressive (-1)

Anonymous Coward | more than 2 years ago | (#38043142)

Dur Apple hating is fun. Group think, nerd rage, lets waste all our energy disliking stuff and telling the internet about it!!1

Re:Not impressive (-1)

Anonymous Coward | more than 2 years ago | (#38043720)

- sent from my iphone

Re:Not impressive (2)

Kazymyr (190114) | more than 2 years ago | (#38043910)

I have used a program that did exactly that on my WinCE PDA, over 6-7 years ago.

Re:Not impressive (0)

Anonymous Coward | more than 2 years ago | (#38045082)

First thing I thought when I read about the app.

Was the program called SonarCE per chance?

Just use a damn tape measure! (0, Informative)

Anonymous Coward | more than 2 years ago | (#38042894)

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.

Re:Just use a damn tape measure! (-1, Flamebait)

Dunbal (464142) | more than 2 years ago | (#38042922)

"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"

But hey, Appletards don't care too much about numbers anyway, they make the head hurt.

Re:Just use a damn tape measure! (2)

hdd (772289) | more than 2 years ago | (#38043138)

"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.

Re:Just use a damn tape measure! (1)

n01 (693310) | more than 2 years ago | (#38043374)

Thanks for clearing this up! I will use the word accuracy in the next update!

Re:Just use a damn tape measure! (1)

abigor (540274) | more than 2 years ago | (#38044074)

Except for all those MB Airs I saw up at Google the other day. Yep, those Google programmers sure don't like numbers. Right?

Re:Just use a damn tape measure! (0)

Anonymous Coward | more than 2 years ago | (#38043312)

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.

Re:Just use a damn tape measure! (1)

n01 (693310) | more than 2 years ago | (#38043364)

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.)

Re:Just use a damn tape measure! (4, Insightful)

DrgnDancer (137700) | more than 2 years ago | (#38043392)

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.

Re:Just use a damn tape measure! (2, Interesting)

artor3 (1344997) | more than 2 years ago | (#38043976)

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.

Re:Just use a damn tape measure! (3, Insightful)

BitZtream (692029) | more than 2 years ago | (#38045202)

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.

Re:Just use a damn tape measure! (1)

Meski (774546) | more than 2 years ago | (#38045464)

No, the tricorder app is cute and clever, and measures a lot more things. Useful? That's debatable.

Re:Just use a damn tape measure! (-1)

Anonymous Coward | more than 2 years ago | (#38044240)

Sorry, I'm not quite following you. Could you perhaps re-state your position with more "fuck"s?

Re:Just use a damn tape measure! (0)

ynp7 (1786468) | more than 2 years ago | (#38045334)

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!

Re:Not impressive (0)

Anonymous Coward | more than 2 years ago | (#38042982)

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). :)

Re:Not impressive (1)

Anonymous Coward | more than 2 years ago | (#38043004)

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.

Re:Not impressive (3, Informative)

hedwards (940851) | more than 2 years ago | (#38043122)

GPS containing units had better be able to do that or they'd never get your location down to something reasonable.

Re:Not impressive (2, Insightful)

Anonymous Coward | more than 2 years ago | (#38043176)

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... :) ).

Re:Not impressive (5, Interesting)

Solandri (704621) | more than 2 years ago | (#38043086)

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.

Re:Not impressive (5, Interesting)

Hartree (191324) | more than 2 years ago | (#38043170)

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. :)

Re:Not impressive (4, Interesting)

Anonymous Coward | more than 2 years ago | (#38043246)

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.

Re:Not impressive (2, Funny)

Nerdfest (867930) | more than 2 years ago | (#38043306)

Sometimes dolphins can be real assholes.

Re:Not impressive (1, Funny)

Anonymous Coward | more than 2 years ago | (#38043724)

No, those are blowholes.

Re:Not impressive (0)

Anonymous Coward | more than 2 years ago | (#38044388)

Sometimes? Dolphins are generally assholes.

Re:Not impressive (2)

fragfoo (2018548) | more than 2 years ago | (#38043416)

I'm curious, how did you figured out it was the dolphins fault? You found interactions in sound recordings?

Re:Not impressive (0)

Anonymous Coward | more than 2 years ago | (#38043932)

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.

Re:Not impressive (-1)

Anonymous Coward | more than 2 years ago | (#38043096)

We all bow before you and your amazing accomplishment of shitting on everything, because THAT takes impressive ability that isn't at all common.

Re:Not impressive (4, Informative)

Anonymous Coward | more than 2 years ago | (#38043206)

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 [wikimedia.org], 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")

Re:Not impressive (2)

n01 (693310) | more than 2 years ago | (#38043342)

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.

Re:Not impressive (1)

CubicleView (910143) | more than 2 years ago | (#38044174)

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.

Re:Not impressive (1)

milkmage (795746) | more than 2 years ago | (#38045148)

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.

wait, dual-device mode? (4, Insightful)

Tyrannosaur (2485772) | more than 2 years ago | (#38042838)

I thought this was going to be a cool sonar thing- you'll need 2 iphones? get a tape measure...

Re:wait, dual-device mode? (1)

polymeris (902231) | more than 2 years ago | (#38042920)

I thought so, too.
The sonar thing sounds difficult. Less cool, but potentially easier: use the camera's autofocus. How accurate could that be?

Re:wait, dual-device mode? (2)

catmistake (814204) | more than 2 years ago | (#38043310)

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.

Re:wait, dual-device mode? (5, Informative)

n01 (693310) | more than 2 years ago | (#38043394)

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.

Star Trek? (5, Funny)

Anonymous Coward | more than 2 years ago | (#38042856)

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."

Re:Star Trek? (1)

Skapare (16644) | more than 2 years ago | (#38043066)

They didn't train the weapons officer to know to do this, yet he could just do it from those words?

Re:Star Trek? (2)

cgenman (325138) | more than 2 years ago | (#38045074)

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."

How about an echolocation app :) (4, Interesting)

TheLink (130905) | more than 2 years ago | (#38042860)

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 [youtube.com]
http://www.youtube.com/watch?v=GYWpxmcHTOc [youtube.com]

Re:How about an echolocation app :) (2)

tokul (682258) | more than 2 years ago | (#38043108)

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.

Re:How about an echolocation app :) (1)

Timmmm (636430) | more than 2 years ago | (#38044128)

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.

Re:How about an echolocation app :) (1)

cgenman (325138) | more than 2 years ago | (#38045110)

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.

Re:How about an echolocation app :) (1)

T-Bone-T (1048702) | more than 2 years ago | (#38045182)

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.

Re:How about an echolocation app :) (0)

Anonymous Coward | more than 2 years ago | (#38044206)

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 [wikipedia.org]

Re:How about an echolocation app :) (1)

tomhudson (43916) | more than 2 years ago | (#38044272)

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!"

This is news because it's on iOS, right? (5, Funny)

QuasiSteve (2042606) | more than 2 years ago | (#38042868)

Because such an app already existed for PocketPC (That'd be Windows Mobile):
http://nerdipedia.com/tiki-index.php?page=Sonar+CE [nerdipedia.com]

Oh, and desktop PC:
http://nerdipedia.com/tiki-index.php?page=Sonar&structure=index [nerdipedia.com]

I hear there's a flashlight app for iDevices, too - Slashdot should really look into that. It's magical.

Re:This is news because it's on iOS, right? (2)

spire3661 (1038968) | more than 2 years ago | (#38043000)

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.

Re:This is news because it's on iOS, right? (2)

QuasiSteve (2042606) | more than 2 years ago | (#38043530)

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 guess the host OS developers like the statistics-inflation caused by the million-and-one flashlight apps, and if one is included then why would a developer still bother? But that doesn't seem like a very strong argument as clearly there are a million-and-one such apps that compete with each other.
Maybe they think the (over)use of the 'flashlight' would cause complaints about battery/emitter life.. especially the LEDs found in current-gen smart phones have pretty serious current draw and if there's no reasonable API to change levels (the camera apps usually use two levels), 10 minutes with the emitter on really eats into power consumption. But that's not a very convincing argument either as most people don't use the flashlight apps for 10 minutes at a time.

Personally, I'm all for having a button - an actual physical button - that turns on the camera LED, on future phones. But I doubt I'll be seeing that anytime soon.

Re:This is news because it's on iOS, right? (1)

tomhudson (43916) | more than 2 years ago | (#38044292)

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).

Re:This is news because it's on iOS, right? (1)

QuasiSteve (2042606) | more than 2 years ago | (#38044610)

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 ).

2009 : Sonar Ruler (5, Insightful)

sugarmotor (621907) | more than 2 years ago | (#38042992)

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 [apple.com]
  * http://thenextweb.com/2009/08/20/amazing-iphone-app-lets-measure-distance-echoes-works/ [thenextweb.com]

Happy measuring!

Re:2009 : Sonar Ruler (-1)

Anonymous Coward | more than 2 years ago | (#38043586)

The problem with all of this is that most phone's microphones are designed specifically to try to eliminate echo reception.

Re:2009 : Sonar Ruler (0)

Anonymous Coward | more than 2 years ago | (#38044798)

Not compatible with iPod touch. Wasted $1. Jerks.

My $0.99 (0)

Anonymous Coward | more than 2 years ago | (#38043032)

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.

Re:My $0.99 (0)

Skapare (16644) | more than 2 years ago | (#38043080)

So where's the Android app to do this? Oh wait, it would probably spam everyone in the room, first.

Accessibility (0)

Anonymous Coward | more than 2 years ago | (#38043136)

I wonder if this could be coupled with Siri to give blind people info about their surroundings.

Re:Accessibility (0)

Anonymous Coward | more than 2 years ago | (#38043278)

Siri: Ooo look, there's another iPhone 7 meters north

"Novel"? Really? (3)

pipedwho (1174327) | more than 2 years ago | (#38043148)

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.)

Re:"Novel"? Really? (0)

Anonymous Coward | more than 2 years ago | (#38044472)

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.

Re:"Novel"? Really? (4, Informative)

pipedwho (1174327) | more than 2 years ago | (#38045052)

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.

Stand-alone (3, Insightful)

soundguy (415780) | more than 2 years ago | (#38043186)

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.

$1,200... (1)

Anonymous Coward | more than 2 years ago | (#38043626)

...seems a little expensive for a tape measure.

fir5t (-1)

Anonymous Coward | more than 2 years ago | (#38043636)

everyday...Redefine have their moments Darren RRed, which lube is wiped off in ratio of 5 to result of a quarrel too many rules and Gains market share the BSD license, Jesus Up The and piss cocktail. ASSOCIATION OF successes with the TCP/IP stack has towels on the floor some of you have these rules will racist? How is America. You, To the politically I know it sux0rs,

VERY VERY OLD NEWS (0)

Anonymous Coward | more than 2 years ago | (#38043654)

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 (0)

nauseous (2239684) | more than 2 years ago | (#38043676)

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.

Frequency? (3, Interesting)

wisebabo (638845) | more than 2 years ago | (#38043744)

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).

Re:Frequency? (4, Insightful)

Anonymous Coward | more than 2 years ago | (#38044984)

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.

Re:Frequency? (1)

Anonymous Coward | more than 2 years ago | (#38045240)

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

Re:Frequency? (0)

Anonymous Coward | more than 2 years ago | (#38045242)

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

Laser for measuring distance? (1)

Twinbee (767046) | more than 2 years ago | (#38044186)

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

Re:Laser for measuring distance? (0)

Anonymous Coward | more than 2 years ago | (#38044802)

Yes. So hopefully iPhone 5 has a laser!

Re:Laser for measuring distance? (0)

Anonymous Coward | more than 2 years ago | (#38045468)

Yeah, but could you do it with a SHARK??!!

For God Sake (1)

nedlohs (1335013) | more than 2 years ago | (#38045228)

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.

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