Subject:
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Re: Sonar Sensor Problems
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Fri, 30 Oct 1998 19:22:26 GMT
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Original-From:
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Will <willbain@cs.umt.SAYNOTOSPAMedu>
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Reply-To:
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willbain@cs.!StopSpammers!umt.edu
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Viewed:
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1739 times
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Eric Noyau wrote:
> Please more details!
>
> What is your "custom dual sonar interface board"? From our previous email exchange on the list I was under the impression you were just thinking about it. And now you have the whole thing up and running!
>
> So any caveat? Just sharing all the lines but the INIT one is working? Are you using D2 or D3 for the second sonar?
The dual sonar interface board is simply a small (1.5" sq. or so)
experimenter's PC board from Ripoff Shack with the six power diodes, the
one resistor, and three header plugs soldered onto it. One plug goes to
the HB and the other two go to the sonar modules. There's also a jumper
to disconnect ECHO from the second module. Because the wires were
wimpy, I doubled up on the power and ground wires.
I've had the one sonar working for a while now, but just recently I
finished getting both sonars plugged in. The part that works great is
the header plug and ribbon cable part. The part that doesn't work so
great is the shared ECHO. Either one works fine alone, but there is
definite signal contention on the ECHO.
I'm using PD2 for the second INIT, and the BINH is shared by both--no
problem. BTW, in order to use PD2 as a digital out, you need to do a
bit_set( 0x1009, 0x3C ) in the initialization routine instead of the
bit_set( 0x1009, 0x30 ) that's in Fred Martin's sonar.c. I'm not sure
why, but the FAQ said to use 0x3C, and it works.
I think I might try using a couple of blocking diodes, like you
suggested, to see if that clears up the ECHO signal contention problem,
unless someone out there has a better idea. I thought about using a
chip with a single OR gate (if there is such a thing) or using PD3 to
control a multiplexor, but those seem like overkill. Any suggestions?
I promise to post all the details on my web page when I get it all
figured out.
--Will
, ,
__@_/ \_@__ |/
| /__, o @_/
)\ ) ( \ (\/\\,
~~~~~~~~~ ' ` ~~~~~~~~~~~ ` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Wendy Parson, Idealism is fine, but as it approaches reality
Will Bain, the cost becomes prohibitive.
& Tatoosh --William F. Buckley, Jr.
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Message is in Reply To:
 | | Sonar Sensor Problems (fwd)
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| oooo$$$...$$$oooo oo$$$...$$$o oo$$$...$$$o o$ $$ o$ o $ oo o$$$...$$$o $$ $$ $$o$ oo $ $ "$ o$$$...$$$ $$$...$$$ $$$...$$$o $$$o$$o$ "$$$$$$o$ o$$$...$$$ $$$...$$$ $$$...$$$o $$$$$$$$ $$$$$$$ $$$...$$$ $$$...$$$ $$$...$$$ $$$...$$$ $$$...$$$ (...) (26 years ago, 28-Oct-98, to lugnet.robotics.handyboard)
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