# Flicker LED to Simulate Fire



## santafe158 (Jul 14, 2010)

I just recently purchased the Lionel Polar Express starter set and have gradually been making improvements/modifications to it. The basic set isn't the highest quality set I've ever purchased, but is quite nice for what I paid for it.

This set will be used on a public display layout I do at the Redford Theatre in Detroit between November and January, and I want it to replicate many of the scenes in the movie for some of the younger (and older) audience members that attend the shows.

So far, I've replaced the red jewel Lionel used to simulate a marker light on the observation car with a LED unit from Dans Drumheads on Ebay which really gives it a neat look in the dark.

My next desire is to simulate the hobo with his campfire on the roof of one of the passenger cars using a flicker LED from a battery powered Tea Light candle which operates at about 3V DC. Obviously the Lionel set operates on AC power between 0 and 18 volts which won't work for the LED. My question is, what components do I need to use to operate the LED off of AC track power?

Thanks


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## gunrunnerjohn (Nov 10, 2010)

Here's a simple circuit to operate the flickering LED(s) from track power. The 22uh choke is optional, it's there for MTH DCS compatibility.


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## santafe158 (Jul 14, 2010)

Thanks for the diagram. That'll be very helpful.

I recognize all the symbols in there except for the 220 35V one in the center. What component would that be? A capacitor?

Thanks


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## gunrunnerjohn (Nov 10, 2010)

That would be an electrolytic capacitor.  You can use any value from around 47uf and up, the voltage rating should be 35 or 50 volts.


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## santafe158 (Jul 14, 2010)

Cool. It's been awhile since I've taken an electronics course  

Thanks for the help.


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## gunrunnerjohn (Nov 10, 2010)

Take not of the polarity, the + side must go where the + sign is on the diagram. Ditto for LED's, they are polarity sensitive. Naturally, the band on the diode is away from the track voltage, connecting to the + side of the capacitor.


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## santafe158 (Jul 14, 2010)

Thanks for the additional information. I knew about the polarity for the capacitor and LED, but the information about the diode will also be helpful.


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## santafe158 (Jul 14, 2010)

Got it all wired in and working like a charm. Most difficult part was talking myself into drilling a hole into the roof of a brand new passenger car, but it was worth the pain (and could be filled in if I really wanted to restore it).



Can't wait to start running the set on the layout now.


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## gunrunnerjohn (Nov 10, 2010)

Now you just have to animate the hobo.


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