Subject:
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RE: IR Problems
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Newsgroups:
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lugnet.robotics.rcx
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Date:
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Mon, 2 Apr 2007 18:16:00 GMT
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Viewed:
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10932 times
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IR communication is no where near the reliability like a tcp/ip. You can
easily lose a message ... so program must be either extremely simple one way
communication. The sender should be programmed to handle message loss.
What I had the kids done was to push the same sending msg for a lot of times
if it is a simple one way communication. Or, it should keep sending until
receiving a recv msg from the receiver(s)... then other actions follow...
If your two RCXs need to get messages from each other or from the computer,
you will need to incorporate more sophisticated synchronization. Otherwise,
you can easily deadlock yourself. A lot of kids did that.
--E
-----Original Message-----
From: news-gateway@lugnet.com [mailto:news-gateway@lugnet.com] On Behalf Of
Tom Lohre
Sent: Monday, April 02, 2007 11:03 AM
To: lugnet.robotics.rcx@lugnet.com
Subject: Re: IR Problems
In lugnet.robotics.rcx, <dickswan@sbcglobal.net> wrote:
>
> Are you sure your problem isn't interference? How did you "lock out" the
> RCS 1.0 from receiving (and responding) to the direct commands? You have
> two RCXs turned on and sending direct commands from the PC. They will
> both try to respond to the direct commands!
Thanks for your reply. I had to return the 1.0 RCX and motor back to school
today. Those things are like gold. The 1.0 faces the 2.0 and is not in
direct
line of sight of the tower. The 1.0 is just to the side of the tower. I
think my
problem is that I did not include a "wait for mail" after the "send mail" in
the
program running on the 2.0. That would reinitialize the 2.0 to listen which
would mean go back to listening for the next command from the tower. The
2.0
tells the 1.0 when to act via mail. The tower sends data every 13 seconds to
the
2.0. Tom http://tomlohre.com/lego.htm
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Message has 1 Reply:
 | | RE: IR Problems
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| Elizabeth is quite right. It's easy to get collisions on the IR "bus" if two devices are sending (or replying) simultaneously. What I've done in the past with two RCXs is define one RCX as primary that is periodically (every 100 to 250 milliseconds (...) (17 years ago, 2-Apr-07, to lugnet.robotics.rcx)
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Message is in Reply To:
| | Re: IR Problems
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| (...) Thanks for your reply. I had to return the 1.0 RCX and motor back to school today. Those things are like gold. The 1.0 faces the 2.0 and is not in direct line of sight of the tower. The 1.0 is just to the side of the tower. I think my problem (...) (17 years ago, 2-Apr-07, to lugnet.robotics.rcx)
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