SparkFun Forums

[luiznunes]

Hi,
I hope I am on the right topic. ( and sorry for my english )
I am doing a project with a robot, I need some help, if possible. I need to use a separate ultrasound emitter and receiver. so:
- Is it possible to measure at the receiver side the wave transmitted by the transmiter?
- will the ultrasound wave have attenuation at 2 or 3 metters from each other that I can measure?
- they need to be right in fron of each other?

thanks for any help you may give.

[luiznunes]

basically I would like to to something like this:
https://www.youtube.com/watch?v=yHyuzKRZFUY

but using ultrasoud. so instead of making some noise, I use a ultrasound emitter, and have two ultrasound receivers, instead of two normal microphones.

[Valen]

Hi,
I hope I am on the right topic. ( and sorry for my english )
I am doing a project with a robot, I need some help, if possible. I need to use a separate ultrasound emitter and receiver. so:
- Is it possible to measure at the receiver side the wave transmitted by the transmiter?

Receivers receive ('measure' if you will) and transmitters transmit. So I guess, yes.

- will the ultrasound wave have attenuation at 2 or 3 metters from each other

Any sound front that expands will have attentuation. The energy has to spread over a larger area as the wavefront expands.

that I can measure?

How would you be sure of the strength of the transmitted signal, if the transmitter and receiver are seperate? To measure you need a reference.

- they need to be right in fron of each other?

thanks for any help you may give.

Ever heard of shadows and reflections? Or which way are they pointing? Same direction or opposed? Explain why you need this requirement. Not that it likely is going to change anything if they are co-linear.

basically I would like to to something like this:
https://www.youtube.com/watch?v=yHyuzKRZFUY

but using ultrasoud. so instead of making some noise, I use a ultrasound emitter, and have two ultrasound receivers, instead of two normal microphones.

You do realize that the transmitter in this movie is his finger snapping, and the speaker and his mouth making noise!?! The sensor is just a bunch of microphones that senses the volumes on the left and right and compares them. (binaural sensor) More sophisticated solutions compare the phase shift, or time arrival difference and deduct the angle of approach from the microphone displacement.

What are you trying to measure with this?

[luiznunes]

I am trying to do a binaural sensor yes. Basically I need one transmitter and I can have 2 receivers at 120mm from each other and I need them to give information to a motor to point to the transmitter, and maybe using a pre-defined table of distance/signal strength, to calculate the distance.
You think it is impossible?
Thanks for the help.

[Valen]

In general I don't think this is impossible. Plenty of people have experimented with binaural techniques, with variyng amounts of succes. You want to do it with ultrasound noise. That means you'll likely have to make a custom design. Which you probably need to do anyway, as I know of no ready made receiver systems that do what you want. (Not that I know all of them ofcourse) An important condition for succes is that you have a little knowledge and experience with this kind of electronics. Have you experimented with ultrasound ranging devices yet? Maybe made your own analog ultrasound ranging device?

My reason for replying here was more to get a better understanding of what you wanted. As it didn't seem to make much sen sense. But I do not have a solution.

Ultrasound tends to be fairly narrow beams and directional. So I'm not sure if the detection cone is wide enough to make this usefull.

[luiznunes]

So unlike audible sound, ultrasound is always a narrow beam?

[Valen]

I didn't say always, it tends to, or it is often so. It depends on the design of the transmitter/receiver. In many cases the transmitter and receiver are sensitive in a cone of 30-60 degrees wide. This would be desirable for ultrasonic distance measurement equipment. But maybe animal repelant ultrasonic noisemakers have a wider emission pattern.

[luiznunes]

Humm. First of all thank you for your help.
So, I need to find and buy 3 transducers ( 1 for transmit and 2 for receive) and create a circuit for the transmitter and another for the receiver. Then use a comparator to compare both the receivers. And hope this works..

[luiznunes]

Anyone knows where I can buy ultrasonic transducers in Europe? Sparkfun does't have anymore..
I only find range finders..

[skimask]

http://lmgtfy.com/?q=https%3A%2F%2Fwww. ... transducer

[luiznunes]

....

I already google those terms..
and only found range finders
at least in europe. that's why I asked for help, but ok.

[Valen]

If you search for "ultrasound sensors" then you do get many ready made distance sensors. They are popular with robot-builders. But I also found several transmitter and receiver devices. I know for sure conrad.com has them. Even a experimentaion kit for kids.

[luiznunes]

thanks. Conrad has it.