Author Topic: Train destination display - up and running  (Read 11129 times)

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Offline Seekonk

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Re: Train destination display - up and running
« Reply #25 on: December 17, 2015, 06:05:43 pm »
I'm not following which pin you are actually toggling to make this work and how you have connected the rest of the pins.  I just wondering if it is operating as it was intended in the factory design.  The circuitry of IC1 seems intended to stop the display when the output pin goes high.  You said it goes low when the magnet is in position.  The intention may be for motor to stop once the magnet passes.    When i hear the phrase  of voltage sweet  in something digital it makes me think this is operating on the edge.  Anyway, I don't think the connections are clear enough for the next guy who would want to do this.
 

Offline jketterlTopic starter

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Re: Train destination display - up and running
« Reply #26 on: December 19, 2015, 01:07:19 am »
I can see why you are worried, and I share some of your concerns.

Let me clarify this: Even though I posted this in "Repair", these displays are not going back into operation. The complete system has been replaced by newer TFTs a few years ago, and the units I am working on have been decommissioned and in private storage ever since. The flaps no longer match the train lines and destinations, and I don't think anybody is still capable of performing or willing to pay for an update.

It is very likely that I am not running the circuit the way it was intended, due to the fact that I don't have any documents about how it was intended to run. That's clearly not a good thing, but there's really not much I can do about it. I'm still lacking a proper scope, which would certainly give me more insight. There's a certain chance that I will come back once I have access to one (I am actually considering buying one because my workbench is clearly lacking...) since it really bugs me.

With all that given, I'm not aiming for 100% reliability and accuracy here. The units, once rewired, will end up on display at special local exhibitions, at least some of them. Maybe some will end up in people's living rooms. They will not display any viable information, and nobody's gonna rely on them any more :)

The only thing I need to prevent is that one of the units will catch fire or something like that.

About the "sweet spot": I wouldn't exactly consider this a digital circuit, I'm only trying to retrofit some kind of digital control so it can be run again.

And for documentation: I'm working on that. There will be some more schematics and probably a design for an Arduino shield once I'm finished.
 

Offline C

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Re: Train destination display - up and running
« Reply #27 on: December 19, 2015, 02:08:47 am »
You might think back to what was available when these were built.
No computers.
Huge number of displays to control.

This hints that master control would step through a bunch of inputs and make displays match with no memory of what the display is currently showing.
Could be
Select a display.
Rotate to index.
Rotate to flap X

You have one motor working changing flaps.
A motor like that could have turned a rotatory switch to select one of many displays. Two control cables now lets you control a large number of close displays.
This makes it simple to keep expanding with same hardware.
 
Input could have been a rotary dial for a phone system
« Last Edit: December 19, 2015, 02:11:03 am by C »
 

Offline Seekonk

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Re: Train destination display - up and running
« Reply #28 on: December 19, 2015, 08:16:26 am »
I have a friend who would probably love to have one of these signs if it wasn't so far away.  He actually has a monorail train from an amusement park.  Not to hijack the thread, this is an animation project I did for him made out of DC-8 parts and a UNO.    Just wanted to know what pin you toggled as there are several ways you could make this work.  Great job.....I could watch that for hours.
 


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