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 20:04:33 GMT
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Original-From:
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Eric Noyau <noyau@apple*SayNoToSpam*.com>
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Viewed:
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1750 times
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Thanks for doing all this testing and reporting it to us. I do really appreciate it.
And I'll vote for the low tech version: use two diodes...
-- Eric
At 11:22 AM 10/30/98 , Will wrote:
> 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.
>
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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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