Subject:
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Re: Grade Crossing Signal Thingy...
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Newsgroups:
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lugnet.trains
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Date:
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Fri, 17 Dec 2004 23:29:48 GMT
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Viewed:
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1668 times
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In lugnet.trains, Joe Strout wrote:
>
> Next: when controlling a crossing like this from an RCX, is cumulated error a
> problem? I'm talking about imprecision in the position of the arm after many
> up/down cycles. I don't see a rotation sensor on this unit, so how does the RCX
> know exactly where the arm is? Or is the RCX/motor combo so precise that this
> isn't a problem?
Easiest way is to have a stop of some kind at both extremeties of movement, and
introduce some kind of slip into the drive mechanism, like rubber bands or a
slip clutch http://www.peeron.com/inv/parts/60c01
Then each cycle runs the motor longer than it needs, and the clutch slips when
the bar reaches the stop.
You could get away with just having a stop at the bottom (when gate is down),
and timing the lift accurately. That way it is reset once every complete cycle.
ROSCO
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Message has 1 Reply:
 | | Re: Grade Crossing Signal Thingy...
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| (...) How safe is it to routinely torque that slip clutch? I usually put it in for safety, but try not to need it -- something like a rope ladder for the upstairs bedroom. I'm thinking of a situation where a four-year old (and possibly several of (...) (20 years ago, 18-Dec-04, to lugnet.trains)
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Message is in Reply To:
| | Re: Grade Crossing Signal Thingy...
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| I have a couple of newbie questions about things like this. First, how do you protect the motor? In this particular design it looks like you could actually rotate the arm past vertical, which I guess isn't a problem until you hit the ground on the (...) (20 years ago, 17-Dec-04, to lugnet.trains)
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