Homebrew sonar

echolocation

Eddie has an interesting writeup about his experience playing around with echo location. He uses a cheap computer speaker and microphone for all of the measurements. The program he wrote generates a sweeping chirp from 5-20kHz in the space of 4.5 milliseconds. Eddie knows what a perfect echo would look like so he can compare the measured values to the theoretical to determine the distance. For his final test he moved the box while it took 150 measurements. This data generated a parabola showing where the object was in the room. Have a look at his site for more details and his code if you are interested.

20 thoughts on “Homebrew sonar

  1. Interesting hack, I was just thinking about using something like this to homebrew a distance finder between vehicles while driving on the road.

  2. The best hack since a long time! And it really works! Not like the useless radiosonde. How abot locating mosquitos in your appartment? ten mics and it should be possible. Passivly or activly…
    M

  3. I’ve been wondering for awhile if it would be possible to rig a sonar device to find lost remote controls or keys… or something.

    Anyone have any ideas how to rig this to do that?

    Stupid I know, but could be fun.

  4. I’m wondering about doing this in a car, myself, possibly with commercial ultrasonic transcivers. (Mostly because I want the outside of the vehicle to stay reasonable looking.)

    I’m also wondering about trangulation from multiple microphones, possibly with laser-pointers on stepper motors, to kill flying beasties, but that’s a little out there…

  5. Joe: looking at the source for the authors page, i see nothing malicious about it? perhaps you could shed some light?

    Anyway, i think this is an awesome project. perhaps he could do one with ultrasound for more clarity?

  6. i jest did it and danm that is awsome and very easy to make i hooked it up to my laptop went out side did a little mod and found some shit UNDER GROUND!!!!!!!!

  7. This is all very interesting and timely for me. I have been looking into developing some sort of sonar system for one of my robots. I want to use the sound card built into the laptop computer I’m using. This work fits the bill nicely and pushes me in the right direction, I think. Interestingly, the auto-correlation signal looks somewhat like a higher-order Coifman wavelet. Wavelets are being used extensively in radar, sonar, and audio analysis.

  8. I have tried this very same thing and it didn’t seem to be that great. I could tell there was something in the path or that the object is moving farther away but, the thing I didn’t like is there is now way to export the results for programming purposes.

  9. when browsing author’s other pages on his site, upon viewing the main menu, Symantec AV found a _possible_ threat. I’m just saying, I didnt bother to try and see what it was, but I didnt like the idea of it. The AV doesnt get triggered very often at all, so thought I’d pass it along.

    Scan type: Auto-Protect Scan
    Event: Security Risk Found!
    Threat: Downloader
    File: C:DOCUME~1XXXXXAPPLIC~1OperaOperaprofilecache4OPR002~2.HTM
    Location: Unknown Storage
    Computer: XXXXX
    User: XXXXXXXXXXXXXXX
    Action taken: Clean failed : Quarantine failed : Delete succeeded : Access denied
    Date found: Wednesday, July 05, 2006 10:26:51 AM

  10. when browsing author’s other pages on his site, upon viewing the main menu, Symantec AV found a _possible_ threat. I’m just saying, I didnt bother to try and see what it was, but I didnt like the idea of it. The AV doesnt get triggered very often at all, so thought I’d pass it along.

    Scan type: Auto-Protect Scan
    Event: Security Risk Found!
    Threat: Downloader
    File: C:DOCUME~1XXXXXAPPLIC~1OperaOperaprofilecache4OPR002~2.HTM
    Location: Unknown Storage
    Computer: XXXXX
    User: XXXXXXXXXXXXXXX
    Action taken: Clean failed : Quarantine failed : Delete succeeded : Access denied
    Date found: Wednesday, July 05, 2006 10:26:51 AM

  11. Using piezoelectret speaker/mic yeilds better performance underwater no? I have been interested in homebrew sonar a while ago, and discovered that these kinds of speakers/mics work very well underwater.

  12. I could see it work when you have no echos. Did he take multipath in to account? How about phase shift? Then again he’s using not so great speakers and a very low grade mic. Chances are this will only work for a very small room and not be very accurate.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s