Subject:
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Re: Old idea or new idea?
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 3 Nov 2000 00:42:27 GMT
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Original-From:
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Pete Sevcik <sevcik@flash.net^antispam^>
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> but the problem is , Lego doesn't used a standard IR-protocol but a
> carier-based IR-communication.
> And that means filters demodulation and a lot of programming , but the • idea
> is tempting.
> Who makes and publishe it ?
Lego uses standard TV remote control technology, but passes ASCII serial data
instead of TV REMOTE commands.
Before Mindstorms was around, I built (and sold a few) battery operated control
units for use with Lego motors.
This product ran your control program in your PC. It passed commands and read
sensor values through an IR link very similar to the mindstorms link.
It did not perform well. I was able to build an IR link that maintained
communication as the robot moved around, although the distance was somewhat
limited. The big problem was speed. Since the IR link is not a reliable
medium, data needs error detection and recovery. I developed a very
lightweight protocol similar to TCP, which worked fine, but had 4 bytes of
overhead per packet. (One sync byte, one header byte, and two CRC bytes) When
you add this overhead to an IR technology that can only support about 2400
baud, the result is too slow for real time control. Any scheme that tries to
read many sensors using the Mindstorms IR link will have the same problem.
--
Pete Sevcik sevcik@flash.net
Techno-stuff Robotics
http://www.flash.net/~sevcik/
Robotics for FUN !
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Message is in Reply To:
 | | Re: Old idea or new idea?
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| "John Barnes" <lego-robotics@crynwr.com> schreef in bericht news:4.2.0.58.200011...lserver... (...) but the problem is , Lego doesn't used a standard IR-protocol but a carier-based IR-communication. And that means filters demodulation and a lot of (...) (24 years ago, 2-Nov-00, to lugnet.robotics)
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