# dwarf signals from ebay, how to work them



## old464 (Oct 12, 2011)

guys, I got these LED dwarf signals with 3 wires and a resistor to work 12 and 16 volts. Can I wire these to operate on say a lionel push down track unit? or do I have to just run one of the wires to glow. there are 3 colors, so it could be really cool. I also got crossing signals. 

http://www.ebay.com/itm/5-pcs-O-sca...&otn=3&po=LVI&ps=63&clkid=4916301207796562990

that is the listing. 

thanks Chris


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## gunrunnerjohn (Nov 10, 2010)

I have the same ones. 

You need a controller that will run them, and for AC, you should have a diode in series with them as well as the resistor to protect against reverse voltage.

Since you have three separate lamps, you're going to have to come up with something that drives them from a track sensor or sensors. What's a *Lionel push down track unit*? Never heard that term.


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## santafe158 (Jul 14, 2010)

gunrunnerjohn said:


> What's a *Lionel push down track unit*? Never heard that term.


Probably one of these?

Lionel 153C contactor


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## gunrunnerjohn (Nov 10, 2010)

That makes sense, my brain was working slowly. 

That won't run all three lights however, it only has a NO and a NC contact.


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## inxy (Dec 10, 2010)

The 153C contactor is normally used to operate a two color (red/green) block signal. I do not know how to set it up for a three color signal. The bulbs in your signal are LEDs and do not work on AC. Follow whatever gunrunnerjohn says on wiring requirements - he's the LED light man. Gunrunner our posts crossed.

B


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## gunrunnerjohn (Nov 10, 2010)

It depends on the amount of realism you're striving for here. Typically, the block signal would be green to start, when train comes on the block, it would turn red. After the train crosses a sensor indicating it was out of that block would turn it yellow, then after the train crosses yet another sensor indicating it's out of the following block, it would turn green. Normally, sad to say, there's quite a bit of logic if you want to run a number of these realistically on your layout.

There have been discussions on block signals on several model train forums and how to trigger them. I keep thinking maybe this is an opportunity to build a universal signal control box with expansion capability, just don't know if I could sell enough of them to make it worthwhile. The key is coming up with cheap track position sensors to feed the signal controller.

This concept could be expanded to run stuff like crossing signals as well


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## Dave Sams (Nov 24, 2010)

I've seen blocks with red and yellow, yellow and green at the same time. Perhaps you could wire the yellow to stay on constantly.


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## old464 (Oct 12, 2011)

well, the dwarf signals, I could just wire so the 2 colors come on. I just got these just to have some lighting. I have crossing signals also. 

COntactor: 
I just wondered if that 153c contactor could operate these like the lionel dwarf signal. I could wire a green and yellow together constant and the pressure contact could switch this to the red or something. 

crossing lights:

these are also LED and how do you get the crossing lights to alternate? I guess a board like the MTH lights where it alternates the colors in the sign? can you buy these or something like it? 

Actual wiring of these and hookup:

So, I cannot just hook the wiring up to these? A DIODE? what is this? and do you place this coming in from the power source i would imagine. they supplied me a resistor that is supposed to be hooked to the black wire. I really don't know about LED and what you need to make this work. What do I need and where to purchase from. 

any help is super appreciated. I did not spend much on these, but they are cool and I think if I can obtain the stuff the make them work, they will be a nice addition.


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## old464 (Oct 12, 2011)

from what the ebay site says, it looks like I can operate these on the voltage and the specs are given for the mA. They should be able to be hooked up. 

Gunrunner: can I just hook them up? is there harm in doign test lights to it? or will I blow them right off if I hooked up the resistor. they called it the common anode (black wire) you place it on. I am not sure if it matters when you hook it up to a transformer as long as this reisistor is installed in the loop.

Operating Voltage = 1.8V to 2.4V

Operating Current = 18mA to 20mA

will come with resistors for 12V or 16V use

maybe you can enlighten me, I really have no idea!!


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## gunrunnerjohn (Nov 10, 2010)

Well, reverse voltage is a problem for LED's, and you'll greatly shorten their life if you don't provide the diode to limit that. The following cut from a specification sheet is for a typical LED, it happens to be one that I have the datasheet for, but other LED's will have similar ratings. Note that these are absolute maximum ratings, you really don't want to get to them, much less exceed them.

Note that peak voltage with an AC signal of 12V RMS will be way over the 5 volts reverse voltage that the LED will tolerate.


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## T-Man (May 16, 2008)

You can consider this ToyTrain Revue


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## Dave Sams (Nov 24, 2010)

old464 said:


> well, the dwarf signals, I could just wire so the 2 colors come on. I just got these just to have some lighting. I have crossing signals also.
> 
> 
> 
> ...


As I said earlier, I would leave the yellow lights on and have the red and green operate with the track.

As far as the crossing lights, here is what I did:

http://www.modeltrainforum.com/showthread.php?t=6769&highlight=flip+flop

The circuit is way overdesigned, but I have a very limited background, and it worked. In fact, I've just competed a second board.

I've since learned Lionel makes a board #610-2760-300 for one of the crossings. The board is about $10.


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## T-Man (May 16, 2008)

Gee I forgot all about THAT thread.  Time for a second look.


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## Badwolf & Arizona RR (Jun 17, 2011)

What about running the dwarf lights off a 3V-4.5V DC wall-wart type of thing? Or maybe a battery system (which is DC by default).

You'll eliminate the potential A/C problem.

As for the activation problems, maybe some sort of button-type "sensor" in the track bed so it knows when there is a train the block, and when that train has left the block?

It would seem to me that Radio Shack would have something like that.

 <--- still thinking.


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## gunrunnerjohn (Nov 10, 2010)

Well, can you be more specific about that *some sort of button-type "sensor"*, because that's the major issue with making this work.


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## Dave Sams (Nov 24, 2010)

If you wanted to add some action to the layout, you could do something like this






Yes, I've been at it againg with my flip flops.


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## old464 (Oct 12, 2011)

I used a 16v source and attached the resistor they provided. the lights work. So maybe I can use track sensors to operate red to green and steady yellow. that might be cool.

Now I have to figure out the alternate back and forth for the crossings. how does Lionel and MTH do this? 

Thanks 
Chris


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## Dave Sams (Nov 24, 2010)

old464 said:


> Now I have to figure out the alternate back and forth for the crossings. how does Lionel and MTH do this?
> 
> Thanks
> Chris


Not sure what you mean by this.


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## gunrunnerjohn (Nov 10, 2010)

If that source is AC, put a diode in the circuit, or the LED's in the signal will have a pretty short life.


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## old464 (Oct 12, 2011)

hi john, won't the resistor prevent that? or is this what you referred to as the voltage coming from behind in that diagram? I did not try 12 volts. 

if I used DC voltage at 12 would they work? stil need a diode? if I ask Radio shack will they know what I am talking about? the Diode? 

thanks for your help
Chris


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## gunrunnerjohn (Nov 10, 2010)

A typical LED has a maximum reverse voltage of 5 volts, if you connect AC of 12 volts to it, the peak voltage is around 16 volts +/-, far in excess of the LED rating. While the resistor will limit the reverse current, the LED really should never see a reverse voltage higher than it's maximum ratings if you want them to last.

The diode can be almost any signal diode, we're only talking 20 or less milliamps. I have a boatload of 150MA diodes as well as a bunch of 1A diodes that I use for general purpose wiring like this.


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## old464 (Oct 12, 2011)

john, thanks a bunch that explains alot. can you shoot me a pic of a diode so I can go to the SHACK and buy a bunch. I think I will use one of the lionel track depressors you use to control a gateman or crossng signal to activate them. maybe Ill hook up a few of these to one, get those diodes. NOW, basically I hook the resistor on one wire and a diode on I guess the rest of the wires. the dwarfs have 3 wires, and a common with that resistor. so Ill need 3 diodes for each dwarf signal. 

thanks john
Chris


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## gunrunnerjohn (Nov 10, 2010)

How about a much cheaper place to buy them? I routinely buy this kind of stuff from Digikey, they only charge actual shipping, which ends up being a couple of bucks on small orders that ship First Class Mail.

Here are your diodes: IN4005 at DigiKey. For ten or more, they're only 20 cents, far cheaper than Radio Shack.  I normally wait until I have a few items I need and make a larger order so shipping is even less of an issue.


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## PencilPusher (Feb 8, 2013)

*Need help in wiring Lionel dwarf signal*

I'm attempting to wire a Lionel 148 dwarf signal (6-12883) via insulated track using the the extra lamp technique that works great on my 153 signal but all I get is both red and green lamps on together regardless of the train in or out of the insulated section. The 153 has 3 wires; the dwarf 4 wires. In the printed instructions for a 153c contactor both the white (common?) wires are twisted together. I've done the same using the 153 technique and this may be the problem. I'd really like to avoid using the contactor; much prefer insulated track. Any suggestions? Thanks. 
PencilPusher


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## gunrunnerjohn (Nov 10, 2010)

That signal won't work using just an insulated track. You will have to add at least a relay that allows you to power red when you're on the insulated section and green when you're off.


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## PencilPusher (Feb 8, 2013)

Thanks John for the heads up. I've never worked with relays before. Is there an info source hopefully with some diagrams and introductory theory for me to get up to speed?


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## gunrunnerjohn (Nov 10, 2010)

Well, it's fairly simple, let's see if we can help. 

Below is a standard relay, let's assume it's a 12V AC coil for simplicity, and you're using 12V AC accessory power to light the signal.

You'd wire one side of the coil to the accessory power, the other side to the insulated rail. The other side (common) of the accessory power would go to the outside rail connection.

You'd wire the N.C. contacts to the green bulb, the N.O. contacts to the red bulb, and COM lead to the accessory power. The common lead from the signal goes back to the common of the accessory power, same as one side of the coil.

With nothing on the track, the green light is lit through the N.C. contacts. When a train is on the insulated section, the relay is energized, and the N.O. contacts are closed and the red light is lit.


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## Pontiac787 (Aug 14, 2011)

gunrunnerjohn said:


> How about a much cheaper place to buy them? I routinely buy this kind of stuff from Digikey, they only charge actual shipping, which ends up being a couple of bucks on small orders that ship First Class Mail.
> 
> Here are your diodes: IN4005 at DigiKey. For ten or more, they're only 20 cents, far cheaper than Radio Shack.  I normally wait until I have a few items I need and make a larger order so shipping is even less of an issue.


I found a photo detect kit that looks like it would be very easy to build but they are $10 a pop. Page two on this link has a parts list of sorts.http://www.quickar.com/easydetect.pdf It seems that I should be able to get the parts for far less. While searching the Digikey website I can't find anything under "calibration trimmer". Is there a technical name that I should be searching for? Also, is there any way to determine the specifications of the transistor?


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## gunrunnerjohn (Nov 10, 2010)

It's a potentiometer. 

I'd buy one so you have the parts in hand, then you can trace the circuit board, create a schematic, and buy the parts. 

The trickier part is determining the exact type of phototransistor.



I don't know how reliable that might be, it's a simple light detection.


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## KarenORichmond (Nov 14, 2011)

The infrared controller from Lionel will work just fine for that.


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## ftauss (Sep 18, 2012)

http://www.azatrax.com/track-power-relay.html

I bought 4, will let everyone know how they work.


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## Pontiac787 (Aug 14, 2011)

ftauss said:


> http://www.azatrax.com/track-power-relay.html
> 
> I bought 4, will let everyone know how they work.


Thanks. I am looking to switch on some old Marx incandescent lights and a ringing signal. I still need to try out Gunnerrunnerjohn's suggestion of modifying a section of track so that it acts as the switch itself.

Two other questions while I'm thinking of it.

1) If the outside rail can be isolated in situations like using it as a switch what is the purpose of the outside rail on a three rail setup, other than to support the wheels of the train? 

2) Can someone point me to a relay that I could use for a two light signal? I want to keep the green light on as the default then cut the power to the green and switch on the red when a train is present on the crossing track.


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## gunrunnerjohn (Nov 10, 2010)

Supporting the wheels is a good thing, so that's what I use the extra rail for!


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## PencilPusher (Feb 8, 2013)

Thanks very much, gunrunnerjohn on the relay education. I got a Azatrax MRAPR relay wired it in with the help of your diagram and it works great! Clearly a new option for me in wiring track accessories.


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## gunrunnerjohn (Nov 10, 2010)

Glad it worked out for you. :thumbsup:


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