Nice iPhone app lets you acoustically measure distances of up to 25 meters(iqtainment.wordpress.com)

79 pointsby greenalevor 15 Jahren58 comments

iqtainment.wordpress.com

Nice iPhone app lets you acoustically measure distances of up to 25 meters

http://iqtainment.wordpress.com/acoustic-rul

11 comments

This is like the 3rd time I've seen this submitted by a new user account in the last day.

http://news.ycombinator.com/item?id=3227929 (by new user quadrix)

http://news.ycombinator.com/item?id=3221160 (by quadrix again)

http://news.ycombinator.com/item?id=3228256 (by new user greenale)

http://news.ycombinator.com/threads?id=makramer09 (new user or shill account makramer09)

http://news.ycombinator.com/threads?id=jgeorge (new user or shill account jgeorge)

http://news.ycombinator.com/threads?id=alexenko (new user or shill account alexenko)

mkopinskyvor 15 Jahren

He seems to have a WP plugin allowing site.com/ac* to forward to /acoustic-ruler/. I'm not sure whether to consider that smart for allowing typos, or evil for allowing this type of behavior.

syncerrvor 15 Jahren

I used one of the codes on reddit. Though it looks like it's free now.

Nice work!

Couple of thoughts:

- I only have ear phones with a mic. It wasn't immediately clear how I should measure something. Perhaps a tutorial? If I hadn't watched the video first, it would have been difficult.

- It's loud, is there a different frequency that could be used?

- Without any other background info, it leads one to think that the temperature is the only additional variable in the equation. Wouldn't it then be possible to tell the temperature with a known distance?

- Unless I have multiple iOS devices, I can only measure just past a meter (from the video). Combining this with the fact that it's not very precise, it would be much more useful if I could measure longer distances (e.g., sonar).

X-Istencevor 15 Jahren

Free? I still see it listed as 99 cents in the app store.

syncerrvor 15 Jahren

It looks like it's showing up for some as free.

http://www.reddit.com/r/iphone/comments/lz0i6/hello_riphone_...

Amaanvor 15 Jahren

No, it was free. 9 or 8 days ago.

greenalevor 15 Jahren

Thanks for your feedback.

In theory it would be possible to tell the temperature if you have a know distance. The only problem seems to be that the clock of the ADC/DAC is often not running exactly at its nominal frequency. So, if you have a known distance, slide the temperature slider until the result matches (this works even after the measurement is complete). I've thought about this problem but decided against having an additional slider for the clock calibration, because I think that would have been to difficult to understand.

heresyvor 15 Jahren

Not sure if I'm doing something wrong, but even after reading the instructions & watching the video I'm getting odd results which don't match what is in the video at all.

I realize there is a disclaimer that it may not necessarily be accurate, but it varies between 0 and some wildly innacurate value like 30 cm when I'm holding it 1 or 2cm away.

[deleted]vor 15 Jahren

z01dvor 15 Jahren

What's the difference to sonar ruler? http://itunes.apple.com/de/app/sonar-ruler/id324621243?mt=8

All codes are taken :-(

greenalevor 15 Jahren

AFAIK Sonar Ruler works by reflecting the sound off a wall e.g.

My app supports a dual-device mode where you can measure the distance between two iOS devices, and it works reliably up to 25 meters.

aw3c2vor 15 Jahren

Apart from people asking for or giving out codes, has anyone tried it yet and is willing to share his/her experience in an comment worth reading? ;)

ya3rvor 15 Jahren

One quick question:

How accurate is this in noisy environments?

viraptorvor 15 Jahren

If they use some specific waveform that is identified on the other side then it should be either perfectly accurate or fail to measure anything depending on background noice - not lose precision. Reflections from the walls is what I'd be more worried about.

greenalevor 15 Jahren

The biggest source of error is actually the variation in the speed of sound. It increases around 2% when the temperature increases 10°C. Then there is a source of error because it seems the clock frequency of the ADC/DAC on the iPhone is not 100% accurate. If you recalibrate the app with a known distance (by moving the temp. slider until the displayed distance matches the actual distance) it should be pretty precise. No warranties, however. If the noise level is too high, it usually just doesn't show the measurement. There's one other source of error, that was actually the hardest to filter out: The sound doesn't only travel on the shortest path (line-of-sight) but on many paths. And often the sound from the longer paths arrive amplified, compared to the shortest path.

tomkinstinchvor 15 Jahren

It's too bad that the temperature sensor in the iPhone isn't accessible through the public API.

It has the hardware to measure temperature, but we can't use it.

(See: http://www.iclarified.com/images/news/3832/14751/14751.png )

gregschlomvor 15 Jahren

Random guess: this may not be a full temperature sensor but just an on/off switch that is triggered when the temperature is above some limit.

samg_vor 15 Jahren

It would require an Internet connection, but GPS + some weather API would do.

jrockwayvor 15 Jahren

Weather APIs know the indoor temperature?

incongruityvor 15 Jahren

Pairs nicely with my sonic screwdriver...

greenalevor 15 Jahren

Hello HN! Here are some promo codes for you:

    M7TF3KPJH3WX
    KJXW974YELWX
    PE6RANNF4R6Y
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You can redeem them as follows:

1) On your iPhone/iPod/iPad, tap the App Store icon from the Home Screen.

2) Navigate to the New section on the Featured tab.

3) Scroll to the bottom of the list to locate and tap the Redeem button.

4) Enter the promo code and tap the Redeem button in the upper right.

5) Tap done on the Thank You screen, then tap the home button to return to the home screen.

6) After a second, you should see the my app installing. (If the promo code was not used before...)

7) Please upvote if you took a code and leave a comment telling which was your code (so the next person doesn't have to try in vain).

8) If all codes are used up, please reply to this comment, I will then post more. This is more efficient than posting all codes at the start.

eggbrainvor 15 Jahren

I took KJXW974YELWX, I'll definitely let you know what I think of the app.

lachygvor 15 Jahren

Oh well! Looks like they're all gone. Mega cool product you've got there :-)

lachygvor 15 Jahren

Can't respond to your latest, but I took: H9FERRJ3TXJ9

greenalevor 15 Jahren

Thanks for telling! Here are some more:

    37LFWL69JKTT
    L7F9JEEKAT6K
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oneweekwondervor 15 Jahren

7) Please upvote if you took a code and leave a comment telling which was your code (so the next person doesn't have to try in vain).

sigh Looks like nobody read your post seeing all of are used.

[deleted]vor 15 Jahren

axxlvor 15 Jahren

Thanks! I can't respond to your other comment for some reason, but I took EKWRFRRYM6JH

alexenkovor 15 Jahren

I used TF7YAPRHJWH7 (can't reply to latest comment). Thank you!

X-Istencevor 15 Jahren

Thanks so much! Very cool product.

brianxq3vor 15 Jahren

and all gone again :(

greenalevor 15 Jahren

Thanks for reporting this!

    HXRH69ATPNEX
    TF7YAPRHJWH7
    RFPEPJEYMJFP
    WMWWRAWNXAXL
    7RJKAMNA9AFE
    6F93JHNXMHYM
    EKWRFRRYM6JH

unfastenvor 15 Jahren

I used WMWWRAWNXAXL. Thanks, I'll be trying it out a bit later.

Amaanvor 15 Jahren

Yeah, weirdly there wasn't a reply link on your post greenale. Thanks, I got F3K7JNAXWHMF.

greenalevor 15 Jahren

Thanks to soulashell and Amaan for pointing out all codes are gone. Strangely there is no reply link on your posts.

Enjoy some more:

    LKNYJXP6JMKF
    F3K7JNAXWHMF
    T9P4L7JE4LF4
    AYERK4LE33X6
    4KWJETFKJFFR
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nopalvor 15 Jahren

Thanks! I used LKNYJXP6JMKF.

makramer09vor 15 Jahren

thanks! used J7KFM7W737MW

amirmcvor 15 Jahren

all gone

ColinDabritzvor 15 Jahren

I can't reply below (is that an HN feature of some kind?) but all of these:

    JH4FKF7L4MR7
    HALW7E3RWFRN
    AM69Y3A6HLYF
    YNJYRTAFEKLL
    4MJW7RWY346L
    9339EPNA3JT6

Are taken. I would love a chance to play with this app! Thanks.

greenalevor 15 Jahren

Thanks for telling me!

Have some more:

    JH4FKF7L4MR7
    HALW7E3RWFRN
    AM69Y3A6HLYF
    YNJYRTAFEKLL
    4MJW7RWY346L
    9339EPNA3JT6

Thank you HN for your tremendous interest!

ColinDabritzvor 15 Jahren

And now the reply link shows up. I assume there is a reply-delay feature?

These codes are all taken.

greenalevor 15 Jahren

I'm sorry, I don't have any more codes. I got only 50 codes, and posted all of them on the internet already.

The app is available for $0.99: http://itunes.apple.com/us/app/acoustic-ruler-pro/id47508196...

[deleted]vor 15 Jahren

sevvor 15 Jahren

All taken! Any possibility for more?

xukivor 15 Jahren

I took 9339EPNA3JT6. Thanks!

amirmcvor 15 Jahren

Thanks. I took AM69Y3A6HLYF

evo_9vor 15 Jahren

I used: 6F93JHNXMHYM

Thanks!

soulashellvor 15 Jahren

All codes are taken.

[deleted]vor 15 Jahren

X-Istencevor 15 Jahren

All codes have been used at time of writing.

introspectifvor 15 Jahren

fascinating. I'd love a code to try this out if still possible.

greenalevor 15 Jahren

Did you try the codes? Are all taken already? Please let me know because then I will post some more

MasterScratvor 15 Jahren

I'd also love to try this, we're working on indoor positioning here and this is a solution we had been considering. Have you done any test with ultra sounds?

introspectifvor 15 Jahren

yep, no luck. i have a good friend just finishing up his phd in a the field and working on applications for similar technology for european automakers.

[deleted]vor 15 Jahren

jbverschoorvor 15 Jahren

all gone :(

makramer09vor 15 Jahren

more codes please!

10dpdvor 15 Jahren

Oh come on its $0.99 - hardly much to ask considering the amount of time and effort thats been spent on the app.

emmettvor 15 Jahren

Sock puppets are not welcome on Hacker News. Please don't do this.

10dpdvor 15 Jahren

Sock puppet?

emmettvor 15 Jahren

A bunch of new accounts having the conversation that these new accounts are having is highly suspicious to say the least.

polemicvor 15 Jahren

I had an app on my old HTC Touch Pro 2 a couple years ago that did this. Yawn.

gbelotevor 15 Jahren

So? Not being the first to make this kind of app doesn't dimish the coolness of what these guys built.

polemicvor 15 Jahren

For sure, but IMHO it makes this more of an advert than 'news'. It's certainly a much nicer implementation.