Subject:
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Re: RemoteCX 0.0.0.5
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Newsgroups:
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lugnet.robotics
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Date:
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Mon, 1 Sep 2003 05:20:35 GMT
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Original-From:
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Gordon Elliott <GELLIOTT@CSISCsaynotospam.CC>
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Viewed:
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770 times
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> > I took my RCX to the electronics lab at school and hooked it up to an
> > oscilloscope. I really wish I had written down what my professor and I • saw,
> > but the pulses were very fast; I believe they were 20ms each. If that • number
> > is incorrect, it's due to my failing memory, but I know for sure they • were in
> > the millisecond range.
>
> Well Jordan I know a little about DC motor theory. In essence a DC Motor • and a
> DC Generator are the same thing. The amount of ripple (i.e. the frequency • of
> the pulses although frequency is a bad term to use) is dependent on 2 • things:
> the speed of the input shaft and the number of commutation points the • machine
> has. The commutation points are fixed by machine construction. As far as
> controlling motor speed, I don't know if you could get speed low enough • for the
> RCX to pick up the pulse (if indeed the RCX can detect the pulses).
Don't forget that the microcontroller probably puts out pulses to control
the motor's power level. So the pulses one would see in normal operation
have little to do with the pulses of the DC motor comutation. A common
technique to control power level would be "pulse width modulation," and I
see a mention of "ticks" somewhere in this discussion. That would make
sense, as the microcontroller might turn motor on N ticks out of 8, for
example, to give 8 power levels (and off). (If that's 8 total, it might be 0
through 7 of 8 time slots. At least one note
http://graphics.stanford.edu/~kekoa/rcx/ says that other power levels would
be ignored, so 7 and 8 might not differ as all treated as "7" -- someone
with direct knowledge could comment.
-- Gordon Elliott
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Message has 1 Reply:
Message is in Reply To:
 | | RemoteCX 0.0.0.5
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| (URL) beginning of my all-in-one program for controlling the RCX..should eventually have a robot server, webcam image server, the works - everything to fit my needs and hopefully everyone else's too...I'm open to feature requests (just check the (...) (21 years ago, 1-Sep-03, to lugnet.robotics, lugnet.robotics.rcx)
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