Subject:
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Re: So THAT's what it does...
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Newsgroups:
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lugnet.trains
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Date:
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Tue, 9 May 2006 21:33:50 GMT
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Viewed:
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4127 times
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In lugnet.trains, Mathew Clayson wrote:
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In lugnet.trains, Jason J. Railton wrote:
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Final post then - Tim jumped the gun a bit with sidebarring me, as this is
the final image:
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snipped
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What I’d love to be able to do is detect the current flow of a running motor
in the supply wire. Then I could build a simple sound-activated reverser,
that holds off until the train has reached the other end. But, I can’t find
a suitable component to sense the current, that wouldn’t be fried by a
transformer on full power.
This is a nice project for Mindstorms, but I think my solution is a lot
cheaper to implement. I’m currently working on a modification to turn two
switches for shuttling two trains.
Jason R
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Jason, nice work.
I had been toying with the idea of using a RCX or a timer circuit for the
same thing. You can even put a few extra back to back diode isolated tracks
before the end sections to simulate acceleration and deceleration. And get
stopped train detection. http://home.cogeco.ca/~rpaisley4/AutoRevCheap.html
A comonly used “sensor” for track occupancy detection is a pair of power
diodes back to back. Put these in series with the track power connection to
an isolated section of track. When a train moves onto the block, it closes
the circuit, and you get 0.7v across the diodes. The polarity tells you the
direction the the motor is traveling.
http://home.cogeco.ca/~rpaisley4/BODGP.html
http://home.cogeco.ca/~rpaisley4/CircuitIndex.html#24
Mat
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Ah, now that’s a good idea. A couple of diodes in series could cope with the
power, and provide a consistent and measurable cue that current is flowing. I
could use that to turn off a sound sensor whilst the train is moving, then
enable it once the train has stopped at the end. You could then clap to make
the train reverse. Thanks.
I had thought of using more diodes to slow things down, but really I like the
simplicity of the very basic solution - particularly not needing to run lines to
sensors at the ends of the track, and building the controller actually out of
lego.
Jason R
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Message is in Reply To:
 | | Re: So THAT's what it does...
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| (...) snipped (...) Jason, nice work. I had been toying with the idea of using a RCX or a timer circuit for the same thing. You can even put a few extra back to back diode isolated tracks before the end sections to simulate acceleration and (...) (19 years ago, 8-May-06, to lugnet.trains, FTX)
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