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Train sign is displayed in speed-aware LED signs which
make the station-name as-you-pass.
You know those clocks which are only 1 thin line, but when
you spin them, it displays the time on the spinning surface?
I've linked to a bad-example.
As you arrive at a station... you don't know the
name...
you wait for the sign, and it zips passed at 30mph. Which is
fine if it's "nomt" but usless if it's "upper saint giles church
west" ... upper what? i think i needed that... ??
The idea is - the displays for stations are simply poles,
which - as the train goes by display the name of the station
statically to the train. In the dark this would work best -
but if you had 5-10-15 of these signs, The next station
would be clear, and easy to read at any speed. If it was
set-back from the track (100ft) you could read it many
times as it scrolled for each carriage.
I think this is a good idea (unlike my others on this site),
perhaps worth doing? Anybody had the same problem?
bad example of the LED effect i'm talking about... i'll delete this if somebody puts a better one on...
http://www.luberth.com/analog.htm
[nicholaswhitworth, Apr 11 2010]
Like this?
http://www.youtube....watch?v=T7jMNENQOxo
From about 0:48 [coprocephalous, Apr 12 2010]
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Annotation:
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The reason the spinning disc type works is that it is moving relative to the surroundings, so your eye sees the LEDs pass through your field of vision, repeatedly scanning the message and allowing time to read it. |
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As you look out of the train window, your eye sees the scenery as fixed (including the pole) so there is no scanning effect.
Even if you looked out through a narrow slit, forcing your eye to see a scan of the scenery, you would only see the pole (and LEDs) as a momentary flash. |
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"//Won't work//
Will too."
Will not. |
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might work... If you looked directly at the pole it
will appear to flash in a crazy high-speed. However,
if you're looking at the hills in the distance, (or
reading the word) it should work fine. |
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Even if it works, wouldn't it be simpler/easier/cheaper to put a digital display on board the train that would tell you where you are? |
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The Washington DC Metro has speed-aware screens on the walls of the tunnel, like in [copro]'s vid, which is hard to see even when one has a window. The cars also have LED signs inside, up on the ceiling, that scroll the name of the next station, which are nice. |
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Not that a lack of need matters on the Halfbakery. |
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This doesn't seem to work, just on premises. It is designed to take advantage of motion-blurring of a vertical line, I think, but that wouldn't work, because the single line would be in sight for just a fraction. Ten or fifteen of the poles is approaching a screen, and setting the thing back from the track 100 feet pretty much removes the motion blur. |
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This idea is confusingly written, but I am pretty sure that, underneath it all, it isn't a good idea. |
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The problems with this idea are:
1) in bright daylight - the LEDS are going to need
to be B.R.I.G.H.T
2) to get a decent working version you'd need a
Number of 'poles' - say 20? and that's more
expensive.
3) you've also got to pay for electricity which you
don't with signs.
4) is it cheaper or more expensive than having
LED's on the trains ? i don't know. For ONE station -
fitting all the coaches of all the trains, is more
expensive than installing a 'led pole' - but if you're
doing a network-wide change, putting them in
coaches is better. |
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I think it's an interesting (and applicable)
technology (as seen by the youtube link
somebody kindly posted) but it's a bit TOO wacky
and 'fragile' to be taken up. BUT - if you can solve
the brightness, and produce them cheaply, it
might just work. I enjoyed the 'would/wouldn't'
argument a lot. |
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