[mowbot] ultrasound

robin nospam at acm.org
Tue, 24 Sep 1996 15:06:46 +0100

Thomas A Maier <tmaier+ nospam at andrew.cmu.edu> wrote:
> You have to isolate the transmitter from the
> receiver in such an application so that you ONLY get the echo.
I'm not so sure you do. As long as you can measure the strength of
the return, rather than just its presence or absence, you can keep the
transmitter on all the time and watch the varying strength of the echo.
This doesn't work in range-finding applications because you have to
have pulses so you can measure transit time. A range-finder typically
doesn't even try to measure the echo's strength; it even fiddles with
the gain as time passes so it can hear echos for a long way away.

I'll try some experiments. I reckon that a set up like this will do:
tx ## rx
\ /
The analogue output from the receiver will surely have some useful
information content.


R.M.O'Leary <robin nospam at acm.org> +44 973 310035  P.O. Box 20, Swansea SA2 8YB, U.K.