Subject:
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Re: sonar (fwd)
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Mon, 18 Nov 1996 01:57:49 GMT
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Original-From:
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MAR ERICSON <mar@cooper.&stopspam&edu>
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Viewed:
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1016 times
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> > I have a Polaroid unit. This is what it looks like. There is ONE
> > transducer a nd a ranging module(driving circuit). The transducer acts
> > as both a "speaker" a nd a "microphone" as opposed to separate units
> > in the Panasonic case.
> >
> > So...someone correct me if I'm wrong...the Digikey things are
> > missing the dri ving circuitry. As an analogy to the Polariods, you
> > only get the "speaker" and "microphone" part. Thus you have to build
> > this yourself which will cost some $.
>
> yes. the polaroid board is pretty sophisticated, really, in that it
> ramps up the input gain the longer it waits for the ultrasonic
> reflection pulse. this compensates for the exponential falloff in
> "volume" as sound disperses on the way out and again on the way back.
>
> it's possible to build a simple ckt with an oscillator for output, a
> fixed gain input, and a 567-style tone decoder, but this doesn't work
> as well.
>
> if you did do this, the HB's IR output could serve as the oscillator,
> since it's a 40kHz ckt with a power transistor output.
>
> -Fred
Garth,
To get a detailed idea about the device electronics, call (617)386-3965, Polaroid Corp., OEM Components Group.
They will give you FREE literature on this.
I imagine that it will help you if you want to investigate making your own electronics for the dual transducer system.
But...as David said, it will probably be involved and not worth it...unless it's some real custom application. You will have to play with Oscilloscopes and stuff. :)
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