Newsgroups: comp.robotics
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From: dombrows@lds.loral.com (Brian Dombrowski, 5424)
Subject: Re: Measuring distance by ultrasonic
Message-ID: <1994Sep12.131311.13115@lds.loral.com>
Sender: news@lds.loral.com
Reply-To: dombrows@lds.loral.com
Organization: Loral Data Systems
References: <CvxvEM.Kuo@world.std.com>
Date: Mon, 12 Sep 1994 13:13:11 GMT
Lines: 25


OK, I have an idea here based on something I saw in the latest
edition of EE Times.  TI is offering a TMS320 DSP evaluation board
that has, 10 K words of memory, RS-232, and an analog interface
chip with a 12-bit A/D and D/A.  The RS-232 is a nine pin jack,
the A/D and D/A ports have RCA jacks, and there is a jack for
5VDC power.  I comes with a manual, assembler, and application
examples.  The TMS320 runs at 40 MHz.  Cost is only $99.

I wondering if it would be fairly simple to use this eval board
to implement a sonar range finder.  Preferably a hand held one
for underwater use.  I'm thinking that the D/A could be used to
emit a short high frequency tone burst to an acoustic transducer.
Then shortly after this the DSP could sample the A/D, also connected
to a transducer, and wait for the reflected pulse to return.  An
FFT could be implemented on the TMS320 to discriminate the
frequency components of the reflected pusle.  The elapsed time
from the pulse transmission to the time the reflected pusle is
received would be proportional to the distance.  TI seems to
brag about the immense amount of software available for the TMS320
and the TMS320 Software Co-op, so maybe one could get the FFT
code for free.  Any comments or ideas about this?

Bd

