Carriage lighting for DCC layouts, a How-to.

Discussion in 'Hornby RTR' started by Keith M, Sep 9, 2016.

  1. Keith M

    Keith M Staff Member Moderator

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    I've been a bit quiet of late (Thank goodness, do I hear?), due to ongoing work on Daughters bathroom/bedroom conversion, but at last I had some free time to myself today to begin work on 5 of Hattons 'bargain priced' new Southern region Mk1 coaches I bought a few weeks ago. 4 are Hornby, 1 a Bachmann 'Buffet car' (pre-owned), and as all my other coach stock has had lighting installed, I decided it's high time these had the 'treatment', so, for the benefit of those who would love to do likewise, here's a step by step 'how-to'! Much of Hornby's coach stock could almost have been designed with lighting installation in mind (doubtful though!), but there are one or two useful features which help installation, which I'll mention as we go along. Anyway, down to business.......first step is body off, so one clip at each corner, just under the bogies, and the body comes off easily enough, so set this aside, together with the 'interior' and concentrate on the chassis first. Hornby just don't seem to add enough weight in their coaches, so especially if you have sharp curves, you can find they derail, so I remove the steel weight, cut out the un-needed plastic to leave a larger opening approx 134mmx28mm, and use sheet lead flashing cut to this size and glued into place. Even though the lead is heavier than the steel weight, it's still not really enough, so I cut 4 pieces 32mmx22mm, folded double and glued into the openings under the 'interior' seats....I find that this is about right, at least on my layout. This pic shows chassis with steel weight removed, lead cut to size ready for gluing into place.

    Attached files [​IMG]
     
  2. Keith M

    Keith M Staff Member Moderator

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    You'll notice at the right hand end of the 'interior' moulding, that a slot has been cut away facing into the 'corridor'. this is to accommodate the capacitor which sticks out from the circuit board, but it isn't seen after installation, so is of no consequence. This pic shows all the necessary weights now fixed in place.

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  3. Keith M

    Keith M Staff Member Moderator

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    Now for the actual SMD LED's. I use the ones which come on a 5 metre roll, usually about £6-ish from China, but ensure you buy 'Warm White' rather than 'Cool white' or just 'White', as these tend to be very blue tinged, rather like Mercury vapour lamps, instead of the period incandescent lamps. Hornby have thoughtfully left a cutaway area at the top of each compartment division, so plenty of clearance for the LED strip down the centre. Required lengths will vary according to the makeup of each coach interior (Guards or parcels compartments would be mostly unlit I'd imagine), so I start by gluing a strip of white paper or thin card of suitable length and 30mm wide, down the roof interior. This helps light reflectance, and stops and light being visible through thin or light coloured roofs. (You don't want a roof that appears to glow in the dark from the outside!!!). Before soldering the circuit board (more about that later!) lighting connections to the LED strip, you'll need to decide where the circuit board is going to be located/hidden, toilet compartments or corridor ends are the best places, especially so if they are close to the bogies for pickup connections. Once this is decided, shorten the wires as necessary, solder to the LED strip, and fix the strip down the centre of the roof where required, as shown below.

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  4. Sparky

    Sparky Full Member

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    One would think that would be enough weight Keith.
     
  5. Keith M

    Keith M Staff Member Moderator

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    I'm not a 'rivet counter' by any means, but at this stage, I paint the seats and floor of the 'interior', then add passengers into the seats. After all, if you are going to draw attention to the coaches by the nature of them being lit, then it makes sense (to me at any rate!) to give the interior at least some detail. When this is done, the 'interior' can be fitted into the body section, slotting the circuit board into place at the toilet compartment or corridor as required, and feeding the pickup wire down a handily placed slot ready to feed through to the bogie for connection to the pickups.

    Attached files [​IMG]
     
  6. Keith M

    Keith M Staff Member Moderator

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    Hornby have very considerately left sufficient space between the bogie clips themselves, to feed pickup wires through the centre and directly to the pickup itself, so carefully feed the wires through (I drill out the two central holes in the pickup PCB strip to 2mm to allow the wires to feed through this), and clip the body/interior assemblies back onto the chassis itself.

    Attached files [​IMG]
     
  7. Keith M

    Keith M Staff Member Moderator

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    Now you can shorten and solder the wires onto the pickup PCB itself, polarity is of no consequence as it's DCC, and the circuit board rectifies the voltage to DC for the LED's anyway.

    Attached files [​IMG]
     
  8. Keith M

    Keith M Staff Member Moderator

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    ......and here's the completed coach. Now for the other four!

    Attached files [​IMG]
     
  9. Keith M

    Keith M Staff Member Moderator

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    Finally, you'll want to know what the required bits look like, circuit diagram etc. I'm well aware that kits are available for carriage lighting, the ones I've seen are priced around £17-£18 a carriage, that's more than I paid for each carriage, so there's no way I'm paying that price! If you can handle a soldering iron, you can buy the Veroboard (stripboard), diodes, resistors and capacitors, plus the LED's cheaply enough, in fact for about £20, you can buy enough components to do about 10 carriages. I make up the circuit boards in batches of about 6 or so at a time, so you get a little 'production line' going, and it's possible to make the circuit board even smaller than my 'standard' item (I use 6 strips wide, but 5 is equally possible), and my Guards compartment coaches have a red lamp on the back just to round it off, all fed by the same single circuit board. The pic gives some idea of the scale of things. Soldering irons at the ready Guys???
    Keith:avatar:

    Attached files [​IMG]
     
  10. jakesdad13

    jakesdad13 Staff Member Moderator

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    Very interesting project Keith, when I eventually get around to building my Kirk O gauge coaches I would like fit detailed interiors with lighting, but that is way way in the future!

    Cheers, Pete.
     
  11. Toto

    Toto I'm best ignored Staff Member Founder Administrator

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    Hi Keith,

    A great how to. I take it the wheel axles insulate the wheels from each other to prevent a short. The Pick ups actually pick up the power from the back of either wheel.

    Might be another obvious daft question by me but I'll ask it anyway. :oops::avatar:

    The big black thingy on the circuit board I am assuming is the capacitor which will act as a stay alive to keep the lights on if the pick ups intermitantly lose contact with the wheels ?

    Cheers

    Toto
     
  12. Keith M

    Keith M Staff Member Moderator

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    Hi Toto.
    The Hornby wheels are indeed insulated so yes, the pickups bear on the backs of the wheels and collect track voltage. You are correct in your assumption about the 'black thingy' being a capacitor, 470 microfarad 25 volt working which gives about 5 to 7 seconds of light before the LED's go out completely. I've started on the Bachmann buffet car which is a bit more difficult than the Hornby stuff, but nothings impossible with a bit of thought!
    Keith.
     
  13. Toto

    Toto I'm best ignored Staff Member Founder Administrator

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    Hi Keith,

    Thanks for that. It just helps getting into the old grey matter. :avatar:

    Look forward to seeing the Bachmann :avatar:
     
  14. ianvolvo46

    ianvolvo46 Staff Member Moderator

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    And he said ... let there be light ... great 'how to' Keith

    Ian:thumbup::thumbup:
     
  15. paul_l

    paul_l Staff Member Administrator

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    A brilliant and enlightening how-to Keith

    Of course the next step is how to switch them on and off remotely without having to have multiple decoders :scratchchin:

    Paul
     
  16. Keith M

    Keith M Staff Member Moderator

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    Actually Paul, I've just ordered one of MERG's motion detecting carriage lighting switches purely for experimenting with. I haven't bothered with switching my carriage lighting, it's on all the time, pretty much as I remember them being as a 'yoof'. I suppose with all the tunnels on UK lines, it wasn't worth switching carriage lighting off during daylight hours, and my Lenz DCC setup is organised so that track voltage is on permanently unless I use the 'emergency stop' button.
    Keith.
     
  17. paul_l

    paul_l Staff Member Administrator

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    So the next challenge, should accept it, is to get the lights to flicker, when the 3rd rail sparks, gowahn grasshopper, you know you can do it :scratchchin: :thumbs: :avatar:

    Paul

    PS Toto the dark side definately has him now
     
  18. ed

    ed Full Member

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    Great thread Keith :thumbup:

    Just been reading about an easy way to turn carriage lights off........... have a 'insulated track' carriage siding.

    Park the carriages and the lights go out, just make sure the loco pushing them in doesn't go over the rail break (unless it's switched).

    Something else that's been floating around in my head (sad person that I am), is how many lighted carriages could you be running before you have to think about how much additional current is being drawn.

    Don't know the answer or even if it's worth considering, just wondered if anyone has ever done any tests or had any problems.

    Ed
     
  19. Toto

    Toto I'm best ignored Staff Member Founder Administrator

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    Hi Ed,
    I'd think that you'd get away with quite a few as its milli amps that these lights will be drawing from the track. Unless you had dozens of them all on at one time, I wouldn't think there would be an issue.
    cheers
    Toto
     
  20. ed

    ed Full Member

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    Would hope so Toto, don't know what the strips are rated at as opposed to individual LEDs.

    After all milliamps add up to amps, added to locos and accessory decoders etc.

    Some DCC starter systems are not rated much above 2 Amps.

    Don't know, just askin'.

    Ed
     

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