Subject:
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RE: Why do it? Was: multi-device output controller (fwd)
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Newsgroups:
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lugnet.robotics
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Date:
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Sat, 27 Mar 1999 03:00:46 GMT
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Original-From:
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Jim Choate <ravage@einstein.ssz+IHateSpam+.com>
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Viewed:
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1111 times
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----- Forwarded message from Ralph Hempel -----
Subject: RE: Why do it? Was: multi-device output controller (fwd)
Date: Sat, 27 Mar 1999 02:17:09 GMT
> That's easy, you don't have to write software for anything other than the
> RCX and such a convertor would only cost about $25 to $30 a copy.
Hmmm, the RCX tower is a pretty effective RS232 converter...and you will
still need to write special software for the RS232 convertor's interface to the
PC.
----- End of forwarded message from Ralph Hempel -----
Actualy you wouldn't. Use the Perl or RcxCC that's out there now to d/l your
nqc comm server. From it's perspective it's still reading and writing to the
same old 3 input/output ports the same old way. It's only outside of the
RCX that the environment changes and within the context of the nqc program
itself and how it handles the data it reads from the port. The only problem
I see is the very limited variable storage (35 if I understand the
environment correctly). If one wanted to use H8 assembly you could access
these ROM calls directly and pick up quite a bit of speed. As to the IR comm
link, use the same routines that are there now. The Mindstorm manual says it
will communicate up to 90 ft. in long range mode. Even if that was a problem
it wouldn't be a real technical task to build an IR booster. Simply tape a
pair of sensors over the existing detectors on the RXC and use them to drive
or be driven by another set of sensors with higher gain, do the same thing
on the other end. After all the IR tower is nothing more than a LED on the
Tx and a photo-transistor on the Rx. It sounds complicated but it's not. None
of this hardware is more than a couple of dozen pieces total. It's all
buildable by somebody who can get a basic op-amp or digital counter to work.
I don't see any reason one couldn't do a IR <> RF xcvr either. The single
chip ones should work just fine.
I suspect you could use the VB SDK to support all this as well.
I've only been playing with my RCX for about a week (only had it 3 weeks)
and so far I haven't found any reason that one couldn't dynamicaly load and
unload modules into one of the 5 program spaces and then selectively run
them. I'll let you know if I run into any problems as this is one aspect of
the web project I'm working on.
Now as to the issue of throwing the RCX away and going to a SBC. Personaly
that seems like the sensible thing to do to me if your serious. I can buy a
NMI 8031 sbc that supports assembly, C, BASIC, & Forth with all documentation
for $40. It includes keyboard and LCD drivers in its ROM and talks over a
standard serial line. Uses standard format assembly (S-records) files. By
using the Frankenstein assembler environment you can develop on a variety of
platforms and OS'es. Is expandable to several M's of ram. It's smaller, runs
at 11MHz, has a lot(!) more software than the H8 ever thought of having, and
it's easier to service since it comes with a complete schematic. It also has
two spare 8-bit ports availabe for I/O. The RCX is fine if your 12, if your
serious about robots move on to a real computer. That's my $.02, take it for
what it's worth to you.
As to a better development environment, personaly I'd like to see MSW Logo
expanded to support the RCX (it already has the capability to talk to the
serial and parallel ports). Unfortunately there is little chance I'll get an
opportunity to do that myself before my interest wanes and I'm attracted to
some othe project. Such is life.
____________________________________________________________________
The trouble with acting according to your conscience is that
once you start doing it, nobody can trust you any more.
Alexis A. Gilliland
The Armadillo Group ,::////;::-. James Choate
Austin, Tx /:'///// ``::>/|/ ravage@ssz.com
www.ssz.com .', |||| `/( e\ 512-451-7087
-====~~mm-'`-```-mm --'-
--------------------------------------------------------------------
--
Did you check the web site first?: http://www.crynwr.com/lego-robotics
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