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Subject: 
Re: RCX Train Sensor
Newsgroups: 
lugnet.org.ca.rtltoronto, lugnet.trains
Date: 
Tue, 6 May 2003 18:17:53 GMT
Viewed: 
402 times
  
James Mathis wrote:
I have managed an automated working layout of one loop with parallel siding
and two alternating running trains.  The two trains run in opposite
directions.  There are 3 "station stops":  one within each parallel siding
and the third is on the main loop.

It took me a minute to realize what you acheived by running in opposite
directions.  Very nice; it neatly avoids the problem of having to change
the points during the run.


It's been several months since I ran this set-up, but if memory serves me
correctly, I think that the RCX program starts with each train *not*
obscurring any of the light sensors.  This allows the MindStorms program to
set the light sensor value to "see" a "bright" value, rather than a "dark"
value.

Obviously, I'd have to take care to not start the system in an unstable
position, such as having the train motor bridging two isolated segments,
but I think I could make the layout work.  Thanks for the tip. I haven't
tried experimenting to see what range the sensor has; I might get
readings from trains on adjacent tracks if I'm not careful.  Or, in the
case of my Altenburg station, from the track *underneath* :P

I think I'll try building a track-side sensor to complement the
under-track one; that way I could position the magnet to rotate around a
vertical axis and avoid the problem of detecting trains below me.

This system has worked OK in constant background light conditions untill the
RCX "times-out" and shuts itself off.  If the background light changes
significantly, I do have to stop the RCX program, reposition the two trains
so that neither obscurs the light sensors, and then restart the RCX program.
When the RCX program starts, I can sometimes see the light sensor red LED
flash or flicker-- I think it is resetting its "bright" value or "zero".

You can change or disable the timeout on your RCX if you like, using
most of the programming environments (including Lego's own RIS).  It
helps to have a 1.0 RCX with power adapter, though, unless you own a
battery factory :)



Your dark box and dual magnet system looks great and appears to step forward
toward an unconditional "works all the time" configuration.  Love it!

The only non-detect situation I've encountered occurs when a train stops
in such a position that the magnet is in its 'off' position - if you
reboot at that point, it doesn't see the train.  But, the instant the
train starts to move, it detects it, so it's not a big deal.

Jeff



Message has 1 Reply:
  Re: RCX Train Sensor
 
(...) All this RCX controlled automation is great and very impressive, but this (URL) is what happens to third-party manufacturers (re- track cleaner) that are not supported by out community. Did anyone do anything with these reed switches? (22 years ago, 7-May-03, to lugnet.org.ca.rtltoronto, lugnet.trains)

Message is in Reply To:
  Re: RCX Train Sensor
 
In lugnet.org.ca.rtltoronto, Jeff Elliott writes: <snip some description> (...) Jeff, great work! I have managed an automated working layout of one loop with parallel siding and two alternating running trains. The two trains run in opposite (...) (22 years ago, 6-May-03, to lugnet.org.ca.rtltoronto, lugnet.trains)

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