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how a sonar range detector works?


I have now been working with a IR range detector. But i have tried to find some information on how a sonar work, as some of my firends said that it will be better to use.

Any1 know how a sonar for obstracle/range detection work?

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Ok thanks Benbo

If i can get the cash, i might get a SRF10(www.robot-electronics.co.uk), but cost alot here in Denmark. But think it is the best i have found so far, as it is also small, and should be easy to work with. After what i can see on the datasheet.

Hope that i get some extra founds to my project.

And i have some problems with getting the components to make it my self.

Sonar rangefinders can find both the distance to an obstacle and the obstacle itself. Assuming the code is good.

Thanks for your repleys.

Just 1 quick question, BoBBy, can you use the sonar to both detect an obstractle, and to measure the distance to the object?

I made my own sonar. Here is the link to my blog. There is a schematic and a video showing the sound wave sent and recieved on an oscilliscope.

Yeah, that one is kewl, but i use this one's ne555 configuration to make 40khz wave: http://users.encs.concordia.ca/~dave/project/elec.html#Obstacle detection sensor and an lm324 instead of lm358, with 2 Rx, so i get stereo sonar :> 

One transducer generates pack of 40KHz wave, timer starts and it counts until second transducer receives this pack. Using time between transmitting and receiving sound you can calculate distance (sound's speed in air - about 340m/s, depending on wind , pressure and so on).