Subject:
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Re: Future Mindstorm Releases?
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Newsgroups:
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lugnet.robotics
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Date:
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Thu, 2 Sep 2004 00:35:16 GMT
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Viewed:
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3199 times
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In lugnet.robotics, Joe Strout wrote:
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In lugnet.robotics, John Barnes wrote:
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There is absolutely nothing stopping anyone buying bare electronic parts and
sticking them in their own bricks if they want.
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Well, yes, there is, if by “bricks” you mean RCX units -- doing so is
considerably harder than connecting them to other controllers, or so it
appears to me (but I could be all wrong there, I’m just a newbie).
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A relatively simple way to hack together an output expander is to throw a
commercially available DCC controller into a brick[1]:
Each one of these bricks can control two lamps and a motor. Since each of these
DCC bricks is individually addressable, you could string many of the bricks
together on a single RCX output. The main limitation is available power. You’d
probably want to limit the use of the DCC bricks to “accessories” that aren’t
generally powered at the same time, reserving the two other RCX outputs for your
robot’s drive motors.
It’s also possible to parallel the RCX outputs (as is done with my
LDCC train program) to
make more power available to the DCC bus:
Although I haven’t tried it yet, it should be possible to hack the DCC
controller’s circuit board to accept external power from a battery box, thus
overcoming the RCX power limitations.
DCC communicates at rates faster than can be produced by the standard RCX
firmware, so you’ll have to use one of the other programming environments.
Presently, there are DCC drivers for both BrickOS and pbForth.
As to the input expansion issue, the DCC standard has recently been updated to
include a bidirectional communication protocol. I’ve been looking at putting
together a simple circuit connected to an RCX input to read data from the DCC
bus. However, an off-the-shelf bidirectional DCC controller that could be
adapted for use as a sensor input isn’t currently available, so I’ll have to put
something together using a PIC to test the viability of the concept.
Anyways, at the cost of one RCX output port and one RCX sensor port, a 2-wire
I/O expansion bus (based on the DCC standard) and utilizing intelligent nodes
seems achievable.
Mark
[1] Dave Koudys has some nice pics of his original DCC brick on his
site.
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Message has 1 Reply:
 | | Re: Future Mindstorm Releases?
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| (...) DCC? As in (URL)? I had to do a search for that, this is the first I've heard of it. Sounds interesting. (...) That's pretty cool. How fast can you control those outputs? And how difficult is it to program? (The NMRA link to the communications (...) (20 years ago, 2-Sep-04, to lugnet.robotics)
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Message is in Reply To:
| | Re: Future Mindstorm Releases?
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| (...) Sure, and then (as I believe you are pointing out), I have something I can't easily use with RCX. But if I have the MarkIII's sensor board ($20) with the input expander kit ($22), then the IRPD *is* a sensor -- it will plug right in. As will (...) (20 years ago, 1-Sep-04, to lugnet.robotics)
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