Subject:
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Re: control train using rcx
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Newsgroups:
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lugnet.trains
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Date:
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Thu, 12 Feb 2004 13:21:07 GMT
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Viewed:
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1420 times
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In lugnet.trains, Steven Brown wrote:
> Hi im currently doing a project that involves using the RCX to operate a train,
> by using inertia equations. Problem is im not very experienced in using NQC
> lanague. Im using potentiometers as controls on the outputs of RCX i will have
> to write a program for inertia to use these controls to control the speed and
> brakes of the train. On the track i shall be using the hall effect sensor this
> will act as an emergency brake to stop the train before the end of the track.
> Was just wondering if anyone could give me any tips on how to go about
> programing this.
How are you using the potentiometers on the RCX outputs? Are you using them to
step down the motor voltage before it is applied to the tracks? Are you turning
them by hand, or with a LEGO motor? And how are you using the hall effect
device to stop the train? Does it short the track, or is it connected to a
sensor input on the RCX?
I've played with this type of thing a little bit. You can power a train from an
RCX by connecting a motor output to the track. The problem is that the eight
motor speeds don't provide very good speed control, especially if you want
really slow train speeds. You will also want to use a 1.0 RCX so that you can
run it off of an AC "wall-wart" power adapter. Otherwise your batteries will
not last very long.
I have also powered the train with a regular speed controller, but used a
Technic Polarity Switch operated by an RCX motor to turn the power on/off and
even reverse the direction of a train. This is much easier on the RCX (since it
doesn't have to provide the power that moves the train) but it makes it much
harder to control the speed of the train from the RCX. You could use an RCX
motor to turn the dial on the speed controller, which would enable you to
control the speed and direction of a train from the RCX. This might allow you
to mimic the inertial effects of a real train.
I have had very good success detecting trains using a magnetic reed switch,
which is a lot easier to use than a hall-effect device. Simply wire the reed
switch (in series with a 1K resistor) up to one of the RCX sensor inputs and
program it as if it were a standard touch sensor. The train coupler magnets
will close the switch and the RCX knows that a train is passing over the sensor
and can take action accordingly. (see
http://www.drvegetable.com/wks_rrcrossing.html for more details on this.)
If you can provide a few more details about what you are trying to do (and what
you've already tried) there are a lot of people here on LUGNET that can help.
- Chris.
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Message has 1 Reply:
 | | Re: control train using rcx
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| Hi im going to be turning the potentiometers by hand to control the motor of the train. Should i be stepping down the motor voltage will that make any difference?, i will be using the hall effect device on the sensor input of the rcx and it will (...) (20 years ago, 12-Feb-04, to lugnet.trains)
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Message is in Reply To:
| | control train using rcx
|
| Hi im currently doing a project that involves using the RCX to operate a train, by using inertia equations. Problem is im not very experienced in using NQC lanague. Im using potentiometers as controls on the outputs of RCX i will have to write a (...) (20 years ago, 12-Feb-04, to lugnet.trains)
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