The selection of components really isn't critical, I just used what I had lying around. The diodes are 1N4004's, the resistors are 499 ohm, and I have no idea what the specs on the LED's are. Depending on your track voltage and LED specs, 499 ohm may be too low for the resistors. You can calculate what you need given the track voltage and LED specs, but I would just start with 1k and if the LED's are not bright enough drop the value until they are.
Thanks.This is what I had in mind when I posted the question.I was looking for a simple,yet reliable,way to have such signalling system.It's even better,it's not expensive either.I wasn't surprised that someone had thought about it before me though.I'm not an electronician so don't know wich components to select,so could I push it to ask for a little more info?Please and thanks.
Thanks Robert. The first one is the one is like the one I was speaking of. I also had a two resistor version.
I have two versions of the circuit for the LED's in my post above. The top one is for DCC only and the bottom one will work on DCC or DC( The top one will work on DC, but not in both directions.):
These circuits will easily fit within the roadbed of an N-scale Kato or Atlas True Track turnout.
JacktalHowever,I was wondering if I could use track current to power a signal.What I have in mind is using the power routing feature of turnouts by having a small bulb(or LED with appropriate resistors) bridging the electrical gap between the frog and one of the rail.My thinking is that the bulb would be either on or off depending on the frog's polarity,thus being a reliable (and simple) signal as to what direction the TO is thrown.
Jacktal ... However,I was wondering if I could use track current to power a signal.What I have in mind is using the power routing feature of turnouts by having a small bulb(or LED with appropriate resistors) bridging the electrical gap between the frog and one of the rail.My thinking is that the bulb would be either on or off depending on the frog's polarity,thus being a reliable (and simple) signal as to what direction the TO is thrown. Current draw isn't much a worry,I have an 8 amp. command station, so that it could handle a few without a sweat but I was wondering what would happen with the digital signal.Not being sure,I won't try it........
...
However,I was wondering if I could use track current to power a signal.What I have in mind is using the power routing feature of turnouts by having a small bulb(or LED with appropriate resistors) bridging the electrical gap between the frog and one of the rail.My thinking is that the bulb would be either on or off depending on the frog's polarity,thus being a reliable (and simple) signal as to what direction the TO is thrown.
Current draw isn't much a worry,I have an 8 amp. command station, so that it could handle a few without a sweat but I was wondering what would happen with the digital signal.Not being sure,I won't try it........
Don't worry. It won't have any effect on the DCC signal and will work fine, like this:
It does sound possible, as long as you use a seperate decoder for each lighting system and you give the decoders a different address from your locomotive fleet. I wouldn't recommend it though, the track bus is for the train, not lineside lighting accesories.
The Lehigh Valley Railroad, the Route of the Black Diamond Express, John Wilkes and Maple Leaf.
-Jake, modeling the Barclay, Towanda & Susquehanna.
I fully agree that powering decorative lights or any accessory with DCC current wouldn't make sense.I never thow away working accessories,so I have a few power supplies laying around.Powering accessories is no problem to me.
LION uses not DCC, but him has a 15 amp filtered regulated voltage controlled power supply. The most I have drawn from the tracks so far is 3 amps. But when I bought it, I did not know how many amps I would need to run 12 trains (call it 18 "locomotives"). Besides there was no lesser supply as good as this one.
Still I will not put aux stuff on it. Just the trains.
LION has two 5 amp transformers with separate rectifiers providing a total of three outputs: +12 v dc; -12v dc; and GROUND. So 12v to ground or 24v across the top. [LION had gotten a good deal on 24v 4pdt relays, so the extra voltage is used--him bought dozens of the things]
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
Using DCC to power anything not riding the rails is akin to using Perrier water to wash your driveway - it can be done, but who in their right mind would want to?
Accessory lighting and such can be powered from any number of power sources, from AA batteries in series to obsolete computer power supplies. Over the years I have accumulated an array of wall warts in various voltages, toy train power packs, filament transformers... DCC can be used to power detector circuits, but the signals themselves should be powered from another source and simply switched on and off by the detector.
I know it's a temptation to want to power everything from a single source. It's a temptation that should be resisted.
Chuck (Modeling Central Japan in September, 1964)
I wouldn't why waste your precious DCC power on ancillary things? Better to run a separate power bus for all the other goodies.
Simon Modelling CB&Q and Wabash See my slowly evolving layout on my picturetrail site http://www.picturetrail.com/simontrains and our videos at http://www.youtube.com/user/MrCrispybake?feature=mhum
It can be done but is not a good practice. There are many alternatives available for lights and other accessories, such as an old computer power supply or an old DC power pack.
DCC should be used only to run trains and for some specific uses such as NCE Switch-It turnout controllers.
Other methods are cheap enough. Keep rail power out of other stuff.
Yeah, Dave is right. The DCC "waveform" which appears on the track is a modulated square wave, which to first order looks like an AC signal on a voltmeter. It changes all the time to carry the digital command signals. To a LED, it also looks like AC.
The problem, though, is the relatively small amount of power available for running the trains. My Lenz system is a hefty 5-amp system out of the box, but some very good systems only provide 2.5 amps. As your layout gets larger and you start running more and more engines, including sound locos that are more power hungry and perhaps lighted passenger cars that also draw track power, you get closer to the threshold where you'll need a booster to keep up with the load.
Compare that to the relative simplicity and low cost of getting a 12-volt, 5-amp supply to put your lights on. LEDs draw very little, but those little incandescent bulbs are going to require 30-50 milliamps each. It may not seem like much, but experience shows that most of us will keep adding more and more lights until finally the power supply just can't handle them.
It takes an iron man to play with a toy iron horse.
Possible but not recommended.
Dave
Lackawanna Route of the Phoebe Snow
I'm just wondering...can someone use the DCC track power for other purposes (like small bulbs,LED's,etc) without undesirable side effects?I suppose it can be done with the proper resistors but would it interfere with the digital signal sent to the locos?I have no real plan of doing it though but it struck my mind...just curious.Thanks.