Subject:
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Re: Mindstorms Automatic Train Control Questions
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Newsgroups:
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lugnet.robotics
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Date:
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Tue, 30 Oct 2001 23:35:33 GMT
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Original-From:
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Steve Baker <sjbaker1@airmail.+nomorespam+net>
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Reply-To:
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SJBAKER1@AIRMAIL.avoidspamNET
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Viewed:
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612 times
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> Thanks for your help. I am back with more questions. First, is it possible to
> use scout computers like the one in this auction
> http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=1653386680
> to control trains instead of the RCXs? Is looks like they're a lot cheaper, but
> are they not as good as the RCX?
The Scout only has two free inputs and two free outputs, the 'third' output is wired
up to a lamp and the 'third' input to a light sensor - both of which are physically
fixed onto the Scout's case. The light sensor is a little different to the
RCX sensors because it can only return "Light" or "Dark" - although you can program
the threshold at which it chooses which is which.
It's two free 'standard' outputs are not powered - so you can't attach external sensors
that need power - you are basically limited to touch sensors. The motor outputs
seem to be identical to the RCX output though.
The Scout also has a VERY small program memory. You can program it in NQC using
virtually identical code to the RCX (although there are a couple of things it
can't do), dunno about Lego's own programming environment - I don't use that.
You can't reload the Scout's firmware, so no chance to run LejOS or LegOS.
However, I have three of them and I find them quite useful...and they *are* very
cheap compared to RCX's. I find the Scout most useful as a peripheral to the
RCX. I wrote a really tiny Scout program that waits for an InfraRed command
to come from the RCX that tells the Scout to either start/stop/reverse one
or other of its motors, turn it's lamp on or off or tells it to send back it's
current sensor inputs. By 'addressing' each IR message to a specific Scout,
I'm able to have the RCX drive as many motors and read as many sensors as I
have Scout's to connect to. There must be some practical limit because it's
quite hard to get them all lined up so they can all 'see' each other's IR
ports.
However, I built a LARGE robot with 11 motors and 11 switch sensors using
an RCX and four Scouts. All the 'intelligence' in the RCX!
The limitations
of the Scouts' memory doesn't matter in this case because all they do is
read the IR port and do one of a dozen simple operations as a result. That's
packed into about a 30 line NQC program - which is about on the limit of
what the Scout can hold!
Scout's also have some built-in programs that you can't change - they are
clearly intended to drive the kinds of models in the instructions for
the Robotics Discovery Set and aren't very generalized.
You'll also see mention of the 'MicroScout' - that's basically just a
box containing a single motor with a single light sensor and something
that Lego calls 'programmability' - but which really only lets you string
together an utterly minimal set of canned commands in a fixed unchanging
sequence. The Microscout has to be programmed via it's light sensor so
you can't talk to it via the IR tower. I had to program a Scout to send
the programming commands to the Microscout...it was a waste of time.
CONCLUSION:
With care, the Scout can be a useful (cheap!) ADDITION to RCX in
some specific applications.
But: *BEWARE* the MicroScout will almost certainly *NOT* do anything
useful for you. IMHO, they are about as useful to serious robotic
as a JarJar Binks minifig!
Also, the Scout-based RDS set doesn't have an IR tower or the
Lego programming software - you need to have at least on RCX-based
set.
--
NOTE: MY HOME PAGE HAS MOVED TO http://www.sjbaker.org - PLEASE
UPDATE YOUR LINKS AND BOOKMARKS ACCORDINGLY!
----------------------------- Steve Baker -------------------------------
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Message has 1 Reply:
 | | Re: Mindstorms Automatic Train Control Questions
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| (...) The micro scout makes a good 3rd Motor to the Scout. Since you can hook up a Microscout to the RED LED on the Scout and it will act as a third motor. It only has one speed but is back and forth and DOES have a cool ability of stopping it's (...) (23 years ago, 2-Nov-01, to lugnet.robotics)
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