Subject:
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Re: RCX and R/C combined
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Newsgroups:
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lugnet.robotics
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Date:
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Sat, 9 Apr 2005 09:20:19 GMT
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Viewed:
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906 times
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In lugnet.robotics, Mark Bellis wrote:
> In lugnet.robotics, Steve Lane wrote:
> > I've just been experimenting with my RCX to see if it can sense the output from
> > the Lego RC unit.
> >
> > The experiment was fairly successful, I was just wondering though if putting 9v
> > into a sensor port does it any good. Are their any risks in making such a
> > connection?
> >
> > I got a beep when I applied negative current.
> >
> > Any thoughts?
> >
> > Steve
>
> Here's a diagram of the RCX sensor port circuit:
> <http://www.brickshelf.com/cgi-bin/gallery.cgi?i=1067044>
>
> Feeding a voltage of up to +9V (or the RCX battery voltage) will not harm the
> port, as this is what it uses in Active mode (light or rotation sensor). You
> can actually use an external 9V power source with a sensor in passive mode
> (touch or temperature sensor), since the port will measure the voltage as a
> proportion of 9V, just as it does in active mode with its internal current
> source.
>
> However, I recommend limiting the current of an external source to 15mA per
> port, which is the same value as the internal current source.
>
> If you set up the port as a temperature sensor and set the choosing threshold to
> correspond to a voltage a little lower then 9V, it should work.
snip
>
> BTW if you're using the RC receiver to command the RCX, don't expect the RCX to
> be able to drive the RC car motors with enough power. See here:
> <http://www.philohome.com/motors/motorcomp.htm>
> I recommend some sort of RCX power interface, a bit like this (not a finished
> circuit): <http://www.brickshelf.com/cgi-bin/gallery.cgi?i=915453> This would
> need an extra set of batteries though.
I'm only intending to use standard gear motors. Great answear Mark, that's
exactly what I wanted to know.
Steve
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Message is in Reply To:
 | | Re: RCX and R/C combined
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| (...) Here's a diagram of the RCX sensor port circuit: (URL) Feeding a voltage of up to +9V (or the RCX battery voltage) will not harm the port, as this is what it uses in Active mode (light or rotation sensor). You can actually use an external 9V (...) (19 years ago, 8-Apr-05, to lugnet.robotics)
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