Subject:
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DCC and other electrical tinkering in the Lego Train World
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Newsgroups:
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lugnet.trains
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Date:
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Sun, 23 Nov 2003 07:33:13 GMT
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Viewed:
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1692 times
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I noticed a number of posts relating to DCC and the very impressive work that
some people have done to bring this into the Lego train world. I thought I
would open this new thread to tell you about my activities and Lego trains.
I do have a number of 4.5V 12V and 9V Lego trains (maybe 20 total) and I have
converted about 10 9V motors to DCC.
So far I am using a commercial DCC controller (Command 2000 from MRC) which can
conveniently run up to 5 locos.
My project now is to create a DCC controller program to run under Windows and
output DCC format signals via the PC sound card. Of course the sound card
cannot drive anything directly and for that I have built a DCC booster utilising
the National Semiconductor LMD18200. There are a number of circuits on the web
to do this, just Google ' DCC LMD18200'. My tests so far are encouraging.
For sensors I am using reed swithces which detect train couplings, I just glue
the reed switch across one of the rail ties. For input to the PC I am using an
old keyboard chip, I just took the keyboard apart and removed the chip on its
little PCB complete with the connector cable. The PCB has about 10 contacts
along one edge and 12 along another. I just connect the switch between one of
each and every time a train coupling passes the PC receives a keycode.
Unfortunately this method does require a lot of wire, two from every sensor back
to where the keyboard chip is but it is easy and cheap to do. There is another
neat feature in that this method of train detection counts the vehicles that
make up the train so provided trains are not of equal length the software can
identify the train.
I have some more sophisticated ideas for reed switch use but I have yet to test
them out.
I wish I could claim all these things are in operation but so far I have only
tested the various components and concepts. Work and garden etc demand my time
too!
My 4.5 volt trains have been converted to carry 'AA' size rechargeable batteries
and I have fitted copper wire brushes under the battery cars. When the brushes
make contact with an energised section of 12V conductor rail a relay inside the
battery car opens and so stops the train. While the train is stopped the
batteries are being recharged, when power is cut from the conductor rail the
relay closes and the train moves off. I have two of these contra circulating
around a loop with a passing bay controlled by a Lego Control Centre. Fully
automatic and never any collisons.
I am waiting for some 9V motors to die so that I can use them as power pickup
vehicles for use with the 12V trains. It should be feasible to take out a dead
9V motor and put a DCC decoder in there and use this to drive 12V locos.
There are quite a few 12V actuators in my layout from level crossings and 12V
switches. I have attached a few of these to 9V switches and they work quite
well. The secret is to not try and move the yellow lever, I just use a piece of
string (genuine Lego string of course!) glued to the little movable piece, one
way the string pulls it across, when the string is relaxed the spring moves it
back.
Two 4.5V switches have been motorised using a simple motor with pinion and rack
mechanism which the Lego Control Centre gives a short 9V pulse to throw the
switch. This is used in my contra circulating layout.
My Lego layout is a never ending project in a 20x8 space (actually inside a
shipping container).
I think Lego is great, I think Lego trains are especially great! But nothing is
sacred and if I can make it work by drilling a little hole in it and attaching a
bent paper clip I am even more happy!
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