Subject:
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Re: Even better, RIS 1.5, $99.99
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Newsgroups:
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lugnet.robotics
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Date:
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Sun, 9 Jun 2002 21:23:27 GMT
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Original-From:
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Jonathan Spitz <jspiar@yahoo+spamless+.com.ar>
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Viewed:
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614 times
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I have thought about those methods as well, the only problem is when you
don't work with the RCX's for just one robot. When you want to try a little
bit with AI and interactions between different robots you can't have a
master that requests, unless you use it to communicate as a telephone
operator, we would need to find a way in wich two or more robots can
communicate without messing up, as you can't have more than one
"conversation" at a time you can't tell the other robot to wait. If instead
of using IR it used a Radio comm. it would be easier as every robot would
know when the others are talking. This subject still needs lots of
investigation.
Jonathan.
----- Original Message -----
From: "Steve Baker" <sjbaker1@airmail.net>
To: "Jonathan Spitz" <jspiar@yahoo.com.ar>
Cc: <lego-robotics@crynwr.com>
Sent: Saturday, June 08, 2002 7:56 PM
Subject: Re: Even better, RIS 1.5, $99.99
>
>
> Jonathan Spitz wrote:
> > There's one way for solving the problem with multiple IR communications • at
> > the same time. The method used for old computer networks is called a • "token"
> > wich is passed from PC to PC giving each one a chance to "speak". This • could
> > also be used for linking RCX's.
>
> That's actually what my 1xRCX + 4xScout system uses.
>
> Another way to think of it is "Don't talk until the person before you
> has finished speaking". If each machine has a number, you can send that
> number embedded in the message somewhere.
>
> The only problem with a token ring scheme is that if an IR message get's
> "lost" somehow, the token is lost and nobody can talk anymore.
>
> Another way is to have a 'master' computer (the RCX in this case) and
> have the others be 'slaves'. Then the master can send a COMMAND to
> tell a specific slave to reply with (for example) the value of one
> of it's sensors.
>
> Now, the master can talk at any time - unless it just asked for some • information,
> but the slaves are not allowed to talk unless they've specifically been • asked
> for a reply.
>
> The big snag with all this is that the turn-around time for the IR • signalling
> is very slow - so any of these schemes can result in a second or two of • delay
> between a sensor on one of the slave machines being activated and that • fact
> finally reaching the master computer.
>
> > You must also check that the RCX have IR
> > contact by sending a reply to the sender or the token would probably get
> > lost. If any of you get to work on this subject I would be pleased to • see
> > some reults.
>
>
> I should probably write up my RCX/Scout work and put it on my web site
> somewhere.
>
> ----------------------------- Steve Baker -------------------------------
> Mail : <sjbaker1@airmail.net> WorkMail: <sjbaker@link.com>
> URLs : http://www.sjbaker.org
> http://plib.sf.net http://tuxaqfh.sf.net http://tuxkart.sf.net
> http://prettypoly.sf.net http://freeglut.sf.net
> http://toobular.sf.net http://lodestone.sf.net
>
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Message has 2 Replies:
 | | Re: Even better, RIS 1.5, $99.99
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| (...) What makes this REALLY difficult is that the communications medium is error prone - it's all too easy for two robots to get out of IR contact with each other when they are moving around. That makes all the usual protocols very difficult. In (...) (22 years ago, 9-Jun-02, to lugnet.robotics)
| | | Re: Even better, RIS 1.5, $99.99
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| I've been wondering if anybody has any ideas why they chose to go with IR as opposed to RF? The substantial limitations of IR make it highly impracticle for robotics. The only two reasons I can see would be cost or power limitations. I can't imagine (...) (22 years ago, 10-Jun-02, to lugnet.robotics)
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Message is in Reply To:
| | Re: Even better, RIS 1.5, $99.99
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| (...) That's actually what my 1xRCX + 4xScout system uses. Another way to think of it is "Don't talk until the person before you has finished speaking". If each machine has a number, you can send that number embedded in the message somewhere. The (...) (22 years ago, 8-Jun-02, to lugnet.robotics)
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