Model Train Forum banner

1 - 12 of 12 Posts

·
Yard Master & Research
Joined
·
10,691 Posts
Discussion Starter #1 (Edited)
A long time ago the forum was asked about this. I remembered it but never answered. Playing around with my toaster circuit it got revived and I figured it out. All you have to do is understand the controller because the lights are there. You have three terminals center is ground left and right are the coils in use. One will have power.To reference the picture top or bottom will be on.
The design:
I will use LEDs so with AC I pair them up. With this I will have a two sided light. Each pair will have a red and green and each side will have a red and green. Both pairs are connected and a wire will run to the center terminal with a half watt 470 ohms. The end will each have a lead going to the other terminals. Each LED is soldered in reverse to its partner.

That is the verbal description, here is the picture



You may have to switch the outer leads to get the correct color to match the direction.

After writing this I am thinking a two sided light is not practical for a switch. What kind of light should a switch have?

To have two signals, one at each approach of the y, the diagram is divided into left and right to make one signal .
 

Attachments

·
Premium Member
Joined
·
16,666 Posts
T-Man,

Your EE projects are way over my head, but in reading your description (and pic), are you suggesting that the each pair of LED lights somehow acts as if they have directional diodes built in? You say, "Each LED is soldered in reverse to its partner." Is that what's happening? I.e., somehow doing that effectively serves as a directional gate (like a diode) to dictate which way the current flows, and in turn, whether the red or green light goes on?

Do LED lights, by defintion, sort of work like a diode with a one-way direction?

TJ
 

·
Yard Master & Research
Joined
·
10,691 Posts
Discussion Starter #3 (Edited)
TJ you make me laugh.
An LED is a diode.
AC is cycling and constantly reverses direction.
The diode hates that and must be protected from reverse voltage.
The best way to do that is wire them in pairs at opposite poles.
Technically they blink ( protecting each other)at 60 cycles a second but you don't notice it.
This was important for me becuase I eliminated the 1N4001 Diode. This is all from a CTT article by Bob Nelson, a (worshipped Kahuna).
I hope you understand I can't explain everthing, I try to streamline information so that the explanation doesn't drag on.
Now,especially when my projects are getting more complicated.
Good question, it explains why it is designed that way. Depending on the switch location, the top pair or the bottom are on. In DC the gate theory works one led will be on, dependent on current flow when wired back to back.
 

·
Premium Member
Joined
·
16,666 Posts
T-Man,

Got it! Thanks for the LED / diode clarification. Actually makes sense now on my end. I did not know that LED work like a diode ... pretty cool. Makes sense now that they turn on/off at 60Hz in AC, as you describe. I was erroneously imagining LED's as little light bulbs (without the diode function), but that's wrong, I guess.

I am learning, T-Man ... slowly, but surely, thanks to guys like you!

So, with that ... that's a pretty clever (and yet amazingly simple) switch light circuit. Cool!

Thanks,

TJ
 

·
Railroad Tycoon
Joined
·
24,021 Posts
The electrical epoxy man.:D:thumbsup:
 

·
Premium Member
Joined
·
16,666 Posts
T-Man,

Got it! Thanks for the LED / diode clarification. Actually makes sense now on my end. I did not know that LED work like a diode ... pretty cool. Makes sense now that they turn on/off at 60Hz in AC, as you describe. I was erroneously imagining LED's as little light bulbs (without the diode function), but that's wrong, I guess.

I am learning, T-Man ... slowly, but surely, thanks to guys like you!

So, with that ... that's a pretty clever (and yet amazingly simple) switch light circuit. Cool!

Thanks,

TJ

Wait a minute ...

I hate to say it, but now I'm confused again. As I look at your circuit diagram, I can see how that would work as intended if DC current were flowing through the wires ... either red light on or green light on, but not both together.

But in your first post, you said AC power. If that's the case, won't each of the red and green lights oscillate on and off at 60Hz, effectively tricking your eye to think that they are BOTH on???

Seems to me like this should be a DC only circuit.

Set me straight, T ...

TJ
 

·
Yard Master & Research
Joined
·
10,691 Posts
Discussion Starter #7 (Edited)
You are looking at a side view not front. yes both light up with AC. Very different from my reverse light in DC. The point is to make it run with AC. In a pair situation with DC only one would work, then the other when current was reversed. So with two pairs in AC the top or the bottom would light depending on the switch. In DC one light of each pair would light depending on polarity. It takes three wires in AC and two in DC.




The frontal view appears like this.



What is a good light switch design that makes sense?
 

Attachments

·
Premium Member
Joined
·
16,666 Posts
T-Man,

Ohhh ... clever ... very clever, indeed! I didn't think you could pull the rabbit out of that hat, but I stand here eating some humble pie.

You are the EE master ... Jedi Knight status, I think!

As for the switch design, you're talking about the styling of the light housing itself? I'll defer to others on that ... I really don't have much real railroad prototype knowledge.

Thanks!

TJ
 

·
Registered
Joined
·
5,163 Posts
Well, that's all well and good, but when do we get to see you put turn signals on an engine? I envision two trains rushing towards a turnout from opposite directions and one engineer saying to himself, "Darn...if we only had turn signals, I'd know if I'm gonna die in 30 seconds or not!"
 

·
Yard Master & Research
Joined
·
10,691 Posts
Discussion Starter #10
TJ you have switches and use them. What would work for you? What arrangement of lights would help for switch monitoring? Something that you cam view on the table and tell what the switch is doing.

Len, maybe I will work on a red flag appearing with the word "jump."
 

·
Premium Member
Joined
·
16,666 Posts
Sounds like a question for Anton ... he had a pretty Gucci control panel with all sorts of LED readouts on switch positions and the like.

My layout is so simple ... oval with 2 turnouts to dead-end spurs, and 2 turnouts into/out of a siding. In that simple case, I guess green for open pass around the oval, and red if turnouts or siding engaged.

But the permutations of switches on complex layouts is obviously more complicated ... makes my head hurt thinking about it.

Anton's your man, I think ...

TJ
 

·
Yard Master & Research
Joined
·
10,691 Posts
Discussion Starter #12 (Edited)
Red and Green? I guess I will keep this open. It is simple but I am looking for a concept, something better if it exists. Just an idea of a light pattern.

For now, if we have a two sided indicator, the top pair would be green and the bottom red, to show the same indication on each side of what the switch is doing.
 
1 - 12 of 12 Posts
Top