Flashing lights

[Anonymous]

Hello all,

Hoping someone could help with some info. I am building a subway layout with lights like the real one has. I am using LEDs as the light source. I want to have the LEDs flash . I am using whiteLEDS and Blue LEDS. I am using them in a series
white [:o)]
blue [:(]
white [:o)]
blue [:(]
white [:o)]
blue [:(]
I used the smileys but you guys get the idea.
I want the leds to flash back and forth from the blues to the whites and so forth.
Is there any way that this can be done?

Thank you in advance.
Angelo

[Anonymous]

QUOTE: Is there any way that this can be done?

Absolutely, Angelo.

Can I tell you how to do it?

Not for about twenty-five years. What I do know is that there is an Integrated Circuit out there that will alternate power output enough to drive an led or several, and the timing is controllable using either variable resistance or capacitance. I would tell you to go to Radio Shack, but lately they seem to be hiring the hard core unemployed with no electronics knowledge at all. What Radio Shack probably does have is a book of circuits--browse their bookshelf and see if one of the books has a circuit like you need.

[FJ and G]

Angelo,

That is really cool!

Pls share more with us as you progress.

I've used LEDs in the past and noticed that when they are on the same circuit/power source, they flash all together and unfortunately resemble Christmas lights.

Sorry I'm not much of a help, but my guess is that adding several different types of capacitors to the circuit would get them firing out of sequence. Or, you could put them on separate circuits.

I'll stop here and let the experts speak.

BTW, I grew up in The Bronx and when I was a tyke, dreamed of a subway layout.

Someday pehaps?

[Anonymous]

There are some good circuits on the web, but the ones I found presuppose a pretty sophisticated knowledge of electronics.

http://ourworld.compuserve.com/homepages/Bill_Bowden/

Look at the index and especially the one called "Fading Red Eyes." It turns on a pair of LEDs and then slowly turns them off while turning on another pair. Nothing says the LEDs have to be red. There are other circuits there that will fla***he LEDs.

[lionelsoni]

Angelo, it's been many years since I've lived where there was a subway; and I don't recall any blue and white lights. Are these on the trains, on in the stations, or where? Do they flash all the time? How rapidly?

[wrmcclellan]

Washington DC's Metro has white lights that line the platform edge (inset in the concrete) that start flashing (about every second if I recall) when a train is about to arrive (about 30 seconds in advance).

[wrmcclellan]

If you like electronics, here is a site with a circuit for a model rr grade crossing with activation and deactivation sensors. The speed of the flashing may be about right if your application is a "train approaching" indicator. The resistors to the LEDs can be adjusted for more LEDs than the two shown.

http://home.cogeco.ca/~rpaisley4/GC04.html

[lionelsoni]

Yes, I've seen those, Roy.

[Anonymous]

Don't laugh but a few years back we had a string of Xmas lights that had two sets of different colored bulbs on it and they flashed back and forth. There was a control knob at the end of the string that you could turn to increase or decrease the flash sequence. I cut that control unit off and rigged it up to a Lionel crossing signal. When the train hit the insulated rail the two lights on the signal flashed back and forth just like the real thing. Darn thing worked pretty good. Something for you to think about I guess.
Paul

[eZAK]

That's a good one Paul!

I'll keep that in mind.

[eZAK]

Angelo.

Check these sites out; http://www.miniatronics.com/Merchant2/merchant.mvc
http://www.daylightdon.com/

[Anonymous]

Wow, Thanks for all the sites guys, I'm going to check them out.

Dave : I am a Brooklyn boy myself, but the train I am running is a 6 train MTH r-26 set. I will be modeling the old IRT line ( think it turned into the 4,5,6 line later on). Some of the stations are in the bronx, I will post pictures when I'm done.

Bob: There are lights on the subway but they don't flash. they change from red to yellow and red to green. There are three in a station one before the train comes out of the tunnel, one mid station and one at the end of the station, also they are in the tunnels at the switches. They change red when a train just left the station and green when it about a station away. They don't operate like a regular traffic light, the first one out of the tunnel and the middle one turn red and yellow, the last one turns red to green. The two yellow ones are lit when the green one is lit, or they are all red. I'm using blue and white in between stations to give the "tunnels" some action, also because last time I got 100 each white and blue for a 12 bucks from japan, so I have a lot left over(This is an extension of what you explained to me about a year ago on using leds as light fixtures). It worked great, but I never got to fini***he stations.

Paul, I actually saw that on a christmas layout. Whenall the lights were in the house the set ran it almost looked real, especially if you have the dimmer and can control how bright they are.

I think I am going with doug's fade idea, like the way that sounds, also i think i may put some rows in the edges of the platforms.

Thanks all for all the input.
By the way
Can anyone explain that fadeing red eye for me? I'm not too savvy when it comes to reading those schematics.
Thanks again Angelo

[Anonymous]

This is one of my favorite sites, you guys may enjoy it take a look:

http://www.nycsubway.org/

[Anonymous]

With the caveat that I am going to have to breadboard the circuit before I am sure, Angelo, he uses a PNP and an NPN transistor. The two base circuit leads are not too clear, but I am sure that they are wired in parallel (together) so that when one transistor ramps up, the other transistor is ramping down. The LEDs are connected in the collector/emitter circuit so that when the transistor conducts, the LEDs light in proportion to the amount of current. He has designed the circuit to run on a nine volt battery, you could do the same thing, or rectify and smooth a ten volt output from your transformer. The little triangles are "op amps," a schematic convention--what is important is that the number by the connection is the pin number on the Integrated Circuit (LM 324) he used. You don't have to know what's in it or how it works, just hook it up to that pin. The two triangles to the right of the circuit show the pin hook up for the other two op amps in the LM 324. You could actually use that IC to build two of these circuits by using those connections. Pin 7 of the second op amp is the output, and you notice that it feeds back into pin 2 (input) of the first op amp through a 100K ohm resistor (bottom diagram). That resistor controls the frequency of the output, and thus the flashing of the LEDs. Bowden recommends using a variable there to control the frequency.

[4kitties]

Don't forget, guys, that there are many makers of electronics for model railroads that aren't well advertised to O gaugers. Miniatronics is but one, Circuitron is another. If you don't mind dropping a few bucks, why re-invent the wheel? I'm using a Circuitron alternating grade crossing flasher circuit to make my O gauge LED traffic lights flash alternately red in one direction, and yellow in the other. Circuitron's tech support was even kind enough to walk me through what resistor to change to get the flash rate up from 80 per minute to 120. I would think this circuit would control them fine if you don't mind wiring the whites separately from the blues. By the way, I got the LED's to fade like the light bulbs in prototype signals by adding capacitors across the circuit's output. The result is really convincing.

[Anonymous]

Hey Doug,
Thanks for the help. Though I do appreciate it, it sounds a bit too advanced for me!!! Guess its back to the drawing board... may use the circuitron idea, thanks 4kitties, I'll post back with the outcome.

Thanks again
Angelo

[FJ and G]

NYC Pa,

Glad to find a fellow NYer. I livd near and rode 3rd Ave el all thru 1960s. Great memories.

Looking to hear more from you!

[wrmcclellan]

NYC,

Here is a deal for you, $4.95 for a kit. I have also seen these kits in local electronics stores and Fry's Electronics. There is likely a "ballast" resistor that can be adjusted to run more than 1 LED on each side.

http://omnitronelectronics.net/phpstore/index.php?action=item&id=471&prevaction=category&previd=52&prevstart=0

Regards,
Roy