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Discussion Starter · #1 ·
I have an inexpensive Lehmann Toy Train Caboose I am adding windows and lights to. The interior lights are done and powered by brushes on the wheels.

I then remembered I have some "Aristo-Craft 1.8v MARKER LIGHTS FOR LONG CABOOSE" that I bought by mistake several years ago.

That seemed like a cheap way to add marker lights to the caboose except for the 1.8 volt LED's.

I did a search of the archives and found:

Caboose Marker Lamps
http://archive.mylargescale.com/forum/topic.asp?TOPIC_ID=25115

Unfortunately (but understandably) the pictures are now gone and also they were to run the marker lights from batteries while I want to run mine from track power.

I don't know anything about LED's except that they are polarity sensitive and apparently easy to burn out.

The only electronics stores nearby are Radio Shacks. I have a couple of +5V Fixed-Voltage Regulator 7805's and looked at the Adjustable-Voltage Regulator LM317T but neither seemed the right solution based on my very limited knowledge about LED's.

What would be the easiest and hopefully least expensive (Radio Shack) way to power these LED's from track power?

Thanks,

Jerry
 

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jerry i have used the aristo REA lanterns, and as i recall,
they come with an 'in-line' diode which allows them to run off track power-but as i recall its also direction sensitive-easy to play with using a tranny and some alligators -set at about 2 volts and reverse leads and work up in voltage -(its been a couple of years som im hazy)
the rea lights-while inexpensive-have the little high output red leds that face outward only-and do not shine through the green mirrored lens only the red fore and aft -and even if you remove the mirror backing (as i have) the green more or less cancels the red led light
and they are glued together so you have to tear them apart in order to get inside

to me the simple answer is a 1.5 battery holder-or 2 AA's if you connect the lights in series

now to NOT answer your question but ramble.....
otoh if you rip out the guts and clean the lens mirroring, you can use some stock 16 volt bulbs-obviously not suitable for 24 v MTS without some sort of resistor and heat sink-what a pain!
you and i both know my friend-you will only be really happy with lgb US lanterns in the long run
that being said
a wonderful alternative, if you cant get the lgb US lanterns IMHO, are the Tomar G scale lanterns-(they come R-G-G or R-Y-Y)-these look great because they are the correct size-and look particularly good on passenger cars-but i also have them on an original 4065 repainted to C and S
tomars are rated at 12 volts -so at 9 they are bright and will get long life as well
-Tomars -at the simplist can be simply attached to a 9v with a 9v connector tab -get the slightly pricier stiff hard pastic type- pop the roof and connect and play
or for much longer burn time will require a AA battery holder-9volts-and an off on switch-these are superior in every repsect except convenience ie monuting and switch access or cutting or whatever--but they will run a very long time provided you sue a AA holder and the switch -and mount the batterys low and secured with a tack of removable glue to avoid toppling the caboose from shifting battery pack
-the Tomar lights run about $20, and about another 5-7 for a 6xAA battery holder and switch from radio shack-
im sure theres a way to track power for less-and that would be the Accucraft classification light circuit board-$8 complete with lamps!!-just hook the leads to track pick ups -BUT these things seem to only light up to 'passable' brightness at about 10 volts-tehy go from off to on-not a gradual build-big resistor i guess- -if used with the Tomar lanterns, you would need to remove the glued in tomar bulbs-and i dont know if the accucraft bulbs are larger than the tomars-
 

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Discussion Starter · #4 ·
Hi Dave,

What I really need to know is the size of the resistor I need to handle the LED's when powered by a 5 volt regulator.

I understand the bridge rectifier etc. but I don't want to burn out the lights by using the wrong size resistor and I don't have any small resistors to try.

Unfortunately your links that seem to have the information I need go to LSOL and I am no longer a member there.

If you can just tell me the resistor size (ohms) I need to work with the Radio Shack 5V Fixed-Voltage Regulator 7805's I should be ready to get it working.

Thanks,

Jerry


Posted By dbodnar on 06/16/2008 11:13 AM
Hi, Jerry - over the years I have written a number of articles about using LEDs. I think the one you want is titled:

LEDs 102 -Using them Onboard Trains
The other articles are listed at:

Articles
Let me know if that clears things up.
dave
 

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Discussion Starter · #5 ·
Hi Steve,

There are two problems.

First - I really HATE batteries (all batteries). I only ever use batteries when I have given up all hope of doing whatever it is that I am doing without batteries.

Second I am working with a TOY TRAIN caboose that I bought by mistake on eBay and was going to throw away.

I finally decided that the only possible use I might have for the caboose would be to light it, put windows in it, perhaps add marker lights and hang it at the end of a log train. A Santa Fe Toy Train (less than) Bobber caboose is about the last thing I want on a log train.

So far I have cut plastic from scrap clear plastic for windows, used left over LGB contact brushes for wheel contact on LGB spoked wheels that did not fit anything on my layout and the only way I would put marker lights on this $15 caboose would be if I can do it at a very low cost as I may eventually throw or give the caboose away.

It is only because looking at the plain Jane caboose bothers me that I keep trying to make it a little bit more tolerable. I have a spare set of the LGB US Lanterns but the caboose is not worth (to me) the value of the lanterns and the LGB lights I would put in them.

I don't mean to put the poor little caboose down. It would have made a nice child's toy but for me it is an accident I am trying to make barely tolerable.

I appreciate your help but in this case I just want to make the problem go away as cheaply as possible.

Actually I have "fixed" the problem in that I bought two replacement LGB 4 axle Santa Fe bobber cabooses and I have fitted those with LGB ball bearing and LGB metal wheels, LGB ceiling lights, and LGB marker lights. I just have not been able to make myself give or throw this toy train caboose away.

It sort of fixed a different problem in that I bought a Corpet-Louvet loco but could not figure out what the heck to do with it so I stuck a US engineer in it, connected it to a LGB European Sound Car, added some US LGB log cars and the toy train caboose has become a sort of logging caboose (at least until I can figure out something I like better).

For its size I think the Aristo marker lights should be perfect and if it works I may try putting them on some Aristo Bobber Cabooses I have.

Regards,

Jerry



Posted By stevedenver on 06/16/2008 11:13 AM
to me the simple answer is a 1.5 battery holder-or 2 AA's if you connect the lights in series

you and i both know my friend-you will only be really happy with lgb US lanterns in the long run
 

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Jerry - I corrected the links - they now go to articles on my web page.

As to the resistor I would suggest going with a 1000 ohm resistor - that value is high enough that it not going to hurt the LED - if you find that they LED is too dim just put two 1000 ohm resistors in parallel and you will have a 500 ohm that will give you a brighter LED - the quick & dirty test for current limiting resistors is just to try something like 1000 or 500 ohms - give the LED a minute to warm up and touch it to your lips - if you feel any warmth the resistor is too small - if it is cool no harm will come to it.

good luck!

dave

PS I wrote up another article about using LEDs for our local garden railway club - it may help, too.

A Simple Constant
Brightness LED Light 
 

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Dave, great write-up, thank you! In your diagrams you discuss various resistors and regulators, but what about diodes. Are there different ones for different reasons, or is a diode a diode? Does it need to be rated for a specific voltage range?
 

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There are a number of different types of diodes. You DO NOT want zener or Schottky diodes.

For use with LEDs just about any garden variety silicon diode will do - Radio Shack sells a 1 amp 1N4001 that will work well - if you are using higher current devices you can go to a 3 amp or larger diode. Voltage is rarely a problem with these diodes as most are rated for 50 or more and our railroads are usually running no more than 25 volts.

dave
 

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Discussion Starter · #9 ·
Hi Dave,

I think you have given me the solution I was looking for.

While playing around with a volt meter on the rails I wanted to see how a 1K resistor worked (intending to see how it functioned at 5 volts) and I discovered that the LED worked pretty well all the way up to 15 volts DC track voltage and was only measuring 2.1 volts across the resistor & LED. The 1/8 watt resistor did not even heat up.

Radio Shack has a 5 pack 1K ohm 1/2W 5% Carbon Film Resistors for 99 cents.

Granted it is not a great solution or even a good solution but it is good enough for a $15 caboose with inexpensive marker lights even if the lights will only come on going forward.

For me it represents a $1 solution to put two marker lights on the little caboose. I won't need to bother with rectifiers, diodes, capacitors or voltage regulators. It is what I would have done with a filament light bulb but did not expect to be able to do with a LED.

Thanks,

Jerry


Posted By dbodnar on 06/16/2008 2:26 PM
Jerry - I corrected the links - they now go to articles on my web page.
As to the resistor I would suggest going with a 1000 ohm resistor
 

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Jerry, I would add al capacitor across the LED to keep intermittent contact issues from making the led's blink. Also, to keep it simple the LED's can be in series and just use 1 resistor and 1 capacitor.

Try a 220uf capacitor across the led.
 

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Discussion Starter · #11 ·
Hi Dan,

For some reason these LED's will not work in series (that was the first thing I tried).

This is just a quick and dirty fix and the caboose will get very little use. I already burned out one of the four marker lights I have so I want to get them installed and forget them as quick as possible.

If they eventually (or quickly) burn out the caboose will still look better with them instead of the black "lanterns" that are currently on the caboose.

When I get into rectifiers, diodes, capacitors etc. I have to stop and think about polarity and usually burn something up. Resistors are easy enough to use without burning anything up as long as they are big enough.

Regards,

Jerry

Posted By Dan Pierce on 06/17/2008 5:13 AM
Jerry, I would add al capacitor across the LED to keep intermittent contact issues from making the led's blink. Also, to keep it simple the LED's can be in series and just use 1 resistor and 1 capacitor.
Try a 220uf capacitor across the led.
 

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Or the flat side marks the negative lead.
 

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Posted By Jerry McColgan on 06/16/2008 2:02 PM

...and the only way I would put marker lights on this $15 caboose would be if I can do it at a very low cost as I may eventually throw or give the caboose away.







If you get to the throw away part let me know...I'll go dig through your trash!! /DesktopModules/NTForums/themes/mls/emoticons/hehe.gif
 

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Discussion Starter · #16 ·
Hi Michael,

Now that LGB parts have become difficult or impossible to find, "throw away" has taken on a new meaning. Now (to me anyway) "throw away" has become "save for any possible future parts needs."

The very thing that many used to criticize LGB for (commonality of parts between models and re-issuance of the same model with just a different paint scheme) has become a great asset as parts from broken or disused models may have the very parts needed to fix other LGB models.

Cheers,

Jerry


Posted By Michael Tollett on 06/23/2008 7:57 AM
If you get to the throw away part let me know...I'll go dig through your trash!! /DesktopModules/NTForums/themes/mls/emoticons/hehe.gif" border=0>
 

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Discussion Starter · #17 ·
To bring this project up to date I finally got back to the caboose and installed the Aristo Marker Lights in the Lehmann Toy Train Caboose using a couple (1 each) 1K 1/2 watt resistors in series with the lights and so far everything looks and seems to work fine.

The little caboose looks much better with the red and green lights instead of the black imitation (Euro) lantern and in the dark or near dark the marker lights show up nicely (not near as bright as regular LGB Marker Lights but good enough for me.

As expected the lights only come on in the forward direction (but at least that shows I got the polarity right).

This was the type of project I like. It was simple and everything I needed I found in my parts bins except for the resistors which cost me 99 cents at Radio Shack.

As usual it is not a solution I would recommend to others but it meets my limited expectations.

Jerry
 

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Next time, add the small radio shack diode bridge to the track power and the lights will work in both directions. The 100ma diode bridge will work just great.
 

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Discussion Starter · #19 ·
Hi Dan,

I just discovered an even better solution.

Necessity and Coincidence are my best learning tools.

In the process of putting the Aristo marker lights into the LGB caboose I found that Aristo had put the red and green lenses in backward (or so I thought).

I then removed the lenses and realized that the LED pointed sideways rather than to the back of the caboose. More important I noticed that the LED was pointed directly at the side marker lens.

It happened that I had blown the LED's of two marker lights so I got to playing with them and found that I could push the burned out LED's through the removed side lens.

My next step was to attempt to replace the LED's with LGB 68513 24V clear plug-in bulbs. The leads of the bulbs were too short for the marker light housing but I drilled out the entry holes to the diameter of the red and black wire insulation. Then I soldered the wires to the 24 volt bulbs and pulled the wires back through the lens opening and out of the marker lights.

After replacing the green and red lenses I now have 24 volt all directional bright marker lights for the LGB caboose.

Encouraged by this I proceeded to remove the unlit marker lights from some Aristo bobber cabooses and found that I can drill through the mountings and install the LGB 24 volt lights in those cabooses as well.

Since I had already added interior lights to the bobber cabooses my net cost of adding lights to the marker lights is only going to be about $2.00 per caboose.

As for Aristo's "mistake" I finally realized that the Aristo marker light's top and bottom were the same and all I had to do was to turn the marker light upside down to reverse the red and green lights. Actually my mistake was a good thing because it led me to realize that I could put the LGB 24 volt lights into the Aristo marker lights.

Some people like LED's but I prefer plain filament light bulbs (sometimes with 5 volt circuits). In this case plain old 24 volt lights work perfect for me.

Jerry



Posted By Dan Pierce on 06/27/2008 4:15 AM
Next time, add the small radio shack diode bridge to the track power and the lights will work in both directions. The 100ma diode bridge will work just great.
 

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Hey Jerry,

While I didn't read through the entire post, what I do to get the correct resistor value is through actual bench testing. Start with a moderately high resistor value, create the circuit and apply voltage with your transformer. Apply voltage meter probes to the pos and neg leads to the LED *AFTER* the resistor and measure the voltage levels as you go up and down through the throttle levels. You will notice the voltage levels the LED sees will change through the various input transformer voltage levels. Keep experimenting with different resistors till you find the one that keeps you LED within the save voltage levels. If the voltage gets too high then you will need a higher resistor. You can purchase a big bag of mixed reistors from Radio shack. In the end I bought a large variety from www.allelectronics.com

Good luck on getting it figured out if you haven't already got it working.


Raymond
 
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