Subject:
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Communicating with CyberMaster
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 16 Oct 1998 10:08:12 GMT
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Viewed:
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1745 times
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A number of people have reported having problems when trying to talk to a
CyberMaster brick using the SPIRIT ActiveX control. I got my CyberMaster set
a couple of days ago and was certainly experiencing the same problems (the
radio tower answers that the brick is alive but is unable to control any of
the motors or read any of the sensors). However, I have found an easy way
around this.
1/ The first thing to do is to set the bricks type using the Spirit>>PBrick
method. This should be set to PB_SPIRIT (0) for the CyberMaster. Normally it
is set to PB_RCX (1) when talking to the MindStorms RC.
2/ The next stage is to unlock the bricks firmware (which I don't really
understand the necessity for since I don't believe it has any firmware
installed). You do this using Spirit>>UnlockFirmware("Do you byte, when I
knock?"). If this works successfully it will answer, "This is a LEGO Control
OCX communicating with a LEGO PBrick!". Note that this operation fails if
you do not have the brick type set to PB_SPIRIT .
3/ Now you just have to unlock the brick itself by calling
Spirit>>UnlockPBrick. After this point you should be able to call the usual
functions in the brick to control motors and poll sensor values etc.
I have noticed a number of differences between the CyberMaster brick and the
standard RCX and I think these are due to the lack of any downloadable
firmware. The first is that it seems only to support 4 tasks rather than the
10 that the RCX can handle. Also, there appears to be only one internal
programme slot. The SelectPrgm() call always fails. I imagine that there may
be several other differences but I haven't come across them yet. Ostensibly
one can write the same sort of programs for CyberMaster as for the RCX.
I tried downloading the FIRM0309.LGO firmware file for the RCX into the
CyberMaster brick to see if this might resolve some of the above problems.
However, this fails with an error message from the brick indicating, "Call
to function '1' . Parameters out of range!". Does anybody have any ideas on
this?
In general, I rather like the CyberMaster set, and I think I may even prefer
it to MindStorms. OK, I know that the brick is a little more limited having
the motors built in but the software on the CD seems rather more
professional (if a little long-winded). I think the fact that example models
are given is better too. I like the way that the CD demonstrates two methods
of programming; being able to control robots directly from the PC and also
downloading a program into the model. The language for downloading programs
is more simplistic than that in MindStorms but, since I don't think much of
the latter's graphical programming system anyway, I don't see that as much
of a problem. Since we now have a number of other methods for programming
the bricks I think this adds weight to the fact that CyberMaster may be a
better choice for many people reading this list.
In particular, the best thing about it is that it uses radio control rather
than infra-red. This makes it much more feasible to write programs that
control robots directly from the PC since they won't keep going out of sight
of the infra-red tower. I have mentioned before on this list that I have
been working on an interface between the RCX and Dolphin Smalltalk. Since
this supports both the downloading mode and the direct control mode I'm
thinking that CyberMaster is ideal for use with this because of its
suitability for the latter mode of control . In fact, it was using this very
interface that I discovered how to talk to the CyberMaster which was really
quite quick to do because of the rapid prototyping nature of the system. I
intend to have a free download available for this interface fairly soon. If
anyone is interested in this then you might like to subscribe to a mailing
list that I have set up for the purpose. Send an e-mail message to
bot-kit@objarts.globalnet.co.uk with SUBSCRIBE as the subject line if you
want to do this.
Does anyone else have any thoughts on CyberMaster versus MindStorms?
Best regards,
Andy Bower
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