It is possible to use just one transducer. I have seen
transformer-coupled systems that works this way. I think it is a little
trickier to get right but also more elegant.


Em 22/10/2013 17:41, Brooke Clarke escreveu:
> Hi Lindy:
>
> These are raw transducers which are much harder to use than range finder =
modules.
> for example:
> https://solarbotics.com/product/40300/
> or
> https://solarbotics.com/product/40310/
>
> Search eBay for ultrasonic range finder.
>
> To roll your own you need to (1) drive the transducer with a short pulse =
of 40 kHz drive and then use a second=20
> transducer as a receiver with a narrow band amplifier centered at 40 kHz =
then envelope detect that.  The two different=20
> model numbers you mention have different bandwidths which determines the =
rise and fall time of the pulse they can=20
> generate.  The range finder modules have done all that for you and probab=
ly for less money.
>

--=20
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