sonar

[ohms]

hey guys i just want to know how the sonar's output look on a oscilliscope and how to read it

thx

 

[zachtheterrible]

sonar is used to measure distance between objects and get a picture of a solid object via sound waves, like dolphins use, or bats. I think that it is usualy used underwater.

If you want to measure distance, you would have to make a calculation based upon the time that the sound is emitted, then received, after being reflected back by a solid object.

To "see" with it, you would need something a lot more advanced than an oscilliscope, i have no idea how that is done.

On an oscilliscope though, all that you would see is a sound wave. I don't think that there's any way of doing much with sonar using an oscilliscope.

i dnt know much about this subject so i might be wrong :lol:

 

[DigiTan]

I don't know if this the type of sonar you had in mind, but if you're looking for acoustic signatures --like an attack sub might-- you could apply some type of simplified spectal analyzer (or even a waterfall display). This approach is more useful in passive sonar applications in my opinion, so it might be useful if you're interested in projects like hydrophones where you have a specific sound signature in mind (a boat, a gasleak, etc).

If you're interested in distance-measuring or collision avoidance, I'd check out Parallax's . In that case, the sonar "pings" could be visible as a train of 40KHz-modulated square waves on a scope. The returned amplitude varied with distance, while the wave period varied occaisionally due to the doppler effect (moving targets involved?). One bot project took their approach even further and had the sonar sweep back and forth in 120-degree arc. A PC was used to combine the echo strenght (base reflectivity) and angle to produce a fairly accurate 2D map. Very interesting stuff!

 

[evandude]

i've never heard of using the amplitude for distance measurement... when it's a LOT simpler to simply filter the receiver with a tone decoder and use the time the pulse takes to return to measure the distance...

 

[ohms]

this is the sonar that i am using **broken link removed**
i think i figured out out the output of the device. but not sure what the signal means. the device have a 11Mhz crystal in it

 

[DigiTan]

That's a tough one (not much data in the web about DM S50). I'm pretty certain the 11MHz XTAL is driving the µcontroller--unless that frequency is being divided. Does it have some kind of data interface or a connector?

 

[pradeep_vesker20008]

hi
anyboady know about sonar in detail with prototype circuit?

 

[Externet]

hey guys i just want to know how the sonar's output look on a oscilliscope and how to read it

thx

It looks like bursts of sinewaves.
The sinewaves are the ultrasonic carrier, the vertical span is its amplitude ; the duration of the burst is one parameter measured in time; the silence between bursts is another time measured parameter. There is other considerations as noise and distortion.

Something like these:

http://ve6atv.sbszoo.com/platinum/images_wf/mb-line.gif

**broken link removed**

http://www.linkwitzlab.com/images/graphics/10burst1.gif

Miguel