How to illumunate an N scale building ?

Discussion in 'N / Z Scale Model Trains' started by Biased turkey, Apr 10, 2008.

  1. Biased turkey

    Biased turkey Active Member

    I've never seen any article about the subject.
    What kind light bulb is best ? ( I've heard about rice bulb, what is it exactly ? )
    How about LEDs ?
    What if the light bulb burns ? do you have to tear the structure off the layout to replace the light bulb ?
    How do you light the structures ?
    Any info will be much appreciated.

  2. steamhead

    steamhead Active Member

    Hi...I use grain of wheat light bulbs (12 v.) wired to an old power pack so I can reduce the voltage to where they glow softly and will last much longer. At full voltage they will shine very brightly and will have a reduced lifetime. Also, if you have plastic structures, make sure you paint the walls on the inside, as they will tend to glow with the light inside...Not very realistic....This can also be avoided to some extent by lowering the brightness of the light.
    Good luck..!!
  3. ezdays

    ezdays Out AZ way

    I have a bunch of incandescent bulbs rated at 18 volts, and like steamhead, I run them off of an old power pack so that I can vary the intensity. Running them at full voltage would make them too bright and would reduce their life. They already have wires mounted on them so I poke them up through the foam. I can pull them out from underneath and change them if I need to, but running them at even at two volts under their rating will increase their burn life by more than double. LED's might work but I've not tried them. They're not as bright and I think the light is too white for inside buildings.
  4. sabretooth47

    sabretooth47 Member

    I agree with steamhead and ezdays, 12v grain of wheat bulbs are the way to go, they are relatively inexpensive and they come in various colors (white, yellow, green, blue, red, etc...).

    I would not recommend LED's. In some cases you have to use resistors and often they are TOO bright. Check out some of those keychain LED lights to see what I mean.
  5. Mountain Man

    Mountain Man Active Member

    Be sure of the location of the bulbs. Plastics and heat are not friends. :cry:
  6. cdavenport

    cdavenport Member

    Years ago I used incandescent bulbs (grain o wheat's included in that category) but I now use LEDs. LED's will be operating for your grandchildren!

    No resistor needed if you operate them with 3 volts DC. Due to their low current requirements, you can wire a bunch of them in parallel and power them with a 3VDC transformer. Check WalMart's electronic section; I have a variable power module that is rated from 1 to 12VDC. I use it for everything.

    If the LED is too bright for your needs mask it with a white paper screen.
  7. MCL_RDG

    MCL_RDG Member

    Candles are out!

    Don't even think of trying it.:eek:

  8. steamhead

    steamhead Active Member

    Pardon for asking....Are LEDS dimmable..?
  9. Biased turkey

    Biased turkey Active Member

    First thanks to all the nice members on this forum who took some of their precious time to reply.
    It looks like the majority use grain of wheat light bulbs.
    By the way I discovered today that miniature light bulbs are named according to size:
    grain of sand = 1.2mm diameter
    grain of rice = 2.2 mm
    grain of wheat = 3.2 mm

    Interesting suggestions about painting the inside wall to avoid glowing or to dim the light and about just poking the wires through the foam and not gluing the light bulb to the building.

    I found a good link on the subject:
    Model Railway - Realistic Building Lighting.

    Being a retired electronic technician I'm "Biased" toward LEDs.
    Pro: they produce less heat than light bulbs

    Cons: Need a resistor to limit the current , the light produced by a clear led might not be very realistic.

    To steamhead: LEDs are dimmable, you can
    1) change the value of the supply voltage
    2) change the value of the limiting current resistor.
    In both cases you can never exceed the maximum forward current.

  10. ezdays

    ezdays Out AZ way

    Just a couple of things. Since the bulbs are going to be inside the building, it really doesn't matter what size the bulb is. The bulbs I use are about the size of a T1 3/4 LED and they're inside of N scale structures. Painting the inside of the structure is a must, otherwise the light will definitely shine through. This is also when you find the imperfect glue joints since they will show up like a beacon. I also use black paper to block the light to areas that I don't want lit. Rarely is an entire building lit in its entirety.

    Now for LEDs, you can exceed the max forward current, but not continuously. We discussed this in another thread here when someone was concerned about using AC and that the peak voltage was higher than the RMS. I have pulsed LEDs that were rated at 20 mA with a 50 mA, 100 ms pulse every second to achieve a steady "on" look. This was a commercial application and there's no reason to even consider doing this for modeling, but the point is that there are times you can exceed the max current rating without damage. The downside to doing this is that if the electronics stops pulsing the LEDs will frequently blow apart,:eek: inflicting great damage to an engineer's pride.:oops: And you are correct, it is possible to dim an LED with a higher resistor value or by lowering the voltage. Someday I might experiment using a yellow LED since that might be closer than a white one for the lighting you'd find inside a building.
  11. roch

    roch Member

    WOW, flashback to highschool and college. Too bad I never learned much like how to spell. :eek:

    Mr Hanky :mrgreen:
  12. engineshop

    engineshop Member

    I only use LEDs now since I don't have to worry about replacing burned out bulbs.
    I actually use SMD LEDs since they are small and almost the brightness of 1:160 scaled light bulbs and will last forever if you keep the current lower than recommended. I was even thinking of using batteries to power the buildings.
  13. cdavenport

    cdavenport Member

    If you don't want to be concerned with replacing the battery, Wal-Mart (and I suppose other outlets) sells a variable DC power module that goes from 1 to 12 volts. Nice little unit and costs about the same as a pack of alkaline D-cells.
  14. nolatron

    nolatron Member

    After seeing the latest issue of MRR with the article on running LEDs off the DCC bus I may take that route for lightning my N-scale buildings.

    I picked up some parts from AllElectronics to experiment with building the LED component.
  15. pgandw

    pgandw Active Member

    I know it was published in Model Railroader, but that doesn't mean it's a great idea. Your DCC power bus is about the most expensive power source available on your layout. Even though you may be running your LEDs at 15 ma, 10 of them are equal to the draw of an N scale motor. That's one less motor you have power for, or that means one less locomotive before you have to buy another booster.

    An old train set power pack or transformer is ideal, and keeps any DCC problems isolated to the track. Other good sources of power for structure lighting are left over wall warts from toys or electronics that don't work any more, or even a left over computer power supply.

    I am a firm believer in keeping the DCC power for trains on the tracks - motors, sounds, and lights - and keeping everything else powered from a separate power source.

    my thoughts, your choices
  16. nolatron

    nolatron Member

    Hah, that's always true.

    Excellent feedback. My initial thought was just that, it's only 15ma/LED and I can use exisiting bus wiring. But your right, as I get more and more added it'll start taking away from the trains.

    Great advice and I'll stick to this train of thought for the layouts mass lightning.

    I think what I'll do is use the MRR method for indicating bus power as I plan on making all of my industry sidings power switchable (only turn on power when actually needed). Having the LED indicator will just act as a visual aid for the switch.

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