Lighting Up the West Coast Express Part 1

eaelec Dec 8, 2013

  1. eaelec

    eaelec TrainBoard Member

    213
    514
    29
  2. markm

    markm TrainBoard Supporter

    793
    232
    20
    I was wondering if you have you given any thought to using a current limiting diode in place of the regulator and resistors? That's been my plan for my coaches.

    Mark
     
  3. Cleantex

    Cleantex TrainBoard Member

    468
    2
    18
    Another interesting voltage regulator is the MC33375D, not so easy to find but having as big advantage a Control ON/OFF input Pin.
    I have the 2,5 Volt version and it seams that for the moment I am the only customer for it. Very interesting IC that I connected
    already after an Atmel uP and it is working fine. Could also be used to be controlled by a decoder :


    http://www.ebay.de/itm/400460967995?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
     
  4. eaelec

    eaelec TrainBoard Member

    213
    514
    29
    No, I hadn't thought of using them before I saw you post. I looked at the datasheet
    for the 1n5305, there is a parameter called maximum limiting voltage which I don't
    understand.
     
  5. markm

    markm TrainBoard Supporter

    793
    232
    20
    I hadn't thought about CLDs for decades (literally!) until an article in the NMRA last spring. It's a good tutorial and I recommend it. Also Central Semiconductor http://www.centralsemi.com/content/product/cld/index.php , a supplier of CLDs, has some good application notes. You can also use a couple of resistors and a JFET for a multiple device solution. The maximum limiting voltage is the maximum voltage across the CLD which it will still regulate to the specified current. If you consider a white LED that will have a Vf of about 3.6 V, you only need a 5-6 V maximum limiting voltage for Z. I'm considering a higher voltage as I will probably be upgrading to DCC and a CLD solution should work with DCC voltages.

    My biggest concern is purchasing the CLDs. To avoid the high distributor prices, I'd need to buy 100, which is far more than I'll ever use.

    Mark
     
  6. markm

    markm TrainBoard Supporter

    793
    232
    20
    Oh, I forgot to mention that regardless how you power the lighting, I'm anxious to see your mechanical work.

    Mark
     
  7. eaelec

    eaelec TrainBoard Member

    213
    514
    29
    Back to Work Again

    After a long delay I'm getting back to this project. Part 2 should
    be ready some time this week. After installing 2 LEDs in one car
    just to find out if the concept actually works (it did), I realized doing the
    whole train that way was going to be way to tedious. So I laid out
    a printed circuit board with a CAD program an had it fabricated.
     

    Attached Files:

    • PCBs.jpg
      PCBs.jpg
      File size:
      589.5 KB
      Views:
      21
  8. eaelec

    eaelec TrainBoard Member

    213
    514
    29
    At the top of the photo (in the previous post) is the bare PCB which contains
    27 individual circuits. Below you see some built-up boards which have been cut apart.
    To the rigth of the penny are 2 LED coach light boards (the small ones)
    and one 3.3 voltage regulator board. To the left of the penny are 2 constant
    intensity head-lamp circuits I made to upgrade by old Micro-Trains F7s. These
    boards have LEDs on the top and the voltage regulator on the reverse side.
    Here's an upgraded F7 with the shell removed:
     

    Attached Files:

    • F7.jpg
      F7.jpg
      File size:
      150.3 KB
      Views:
      26

Share This Page