Bi-directional lighting on HSTs

[End2end]

I will eventually buy a power car and dummy HST to go with my lit coaches I have made and I intend to DCC the engine (hardwaired via a socket) so that will control the movement of the train.

But is there a way to control the lights so that both the power and dummy car have bi-directional white and red lights and show the correct lights when going in either direction?
I.E.
White headlights on power car / Red on dummy when going forward
Red headlights on power car / White on dummy when going backwards

I envision the dummy car to have some sort of circuit that tells the lights to show one or the other, rather than being connected to the DCC chip right at the other end of the train but I wouldn't have a clue what I need.

Again this is for a future project but I wanted to gather ideas and perhaps an item list what it will take to do this if it's possible.
Thanks
End2end

[Roger (RJ)]

Post deleted. Not sure I'm right.

[Flashbang]

Use the Yellow and White wires on the decoder with the Blue wire which is common to all and the Positive wire. (Yellow and White are switched negatives)
I would put a lighting only decoder in the dummy end rather than trying to through wire from the motor end! You can use a motor and function decoder or just a function only decoder in the dummy end. Both decoders are set to the same address number. If rear units lights work the wrong way around adjust CV29 direction of travel on that decoder to correct.

Wiring for direction of travel controlled DCC lighting is here.... Link to decoder function wiring

[End2end]

I'm assuming that this method would need 2 DCC addresses?

Is there an analogue way to do it?
Picking up the DCC current from the track with some sort of circuitry that would pick up the direction of power?
Or would this only work on DC?
Thanks
End2end

Edit: Flashbang would it be ok to print out that info from your site so I have a paper copy please?

[Bufferstop]

There is an analogue way to do it, DCC's AC supply defeats it.

[TimberSurf]

E2E, says "You may freely and for personal use only, copy or print any areas." on every page!
Just don't make multi copies and start selling them down the open stall market!
DC is easily done with a couple of diodes, but DCC needs the chip (encoder) to interpret the signals to that specific train's direction command.
You could use the engine decoder, but would need wiring down the coaches and connecters between them!
So it's easier to fit a second encoder (cheap one) in the dummy and give it an identical address as the engine (so they both get the same commands), mind that does mean the dummy needs its own pickups!

[End2end]

E2E, says "You may freely and for personal use only, copy or print any areas." on every page!
Just don't make multi copies and start selling them down the open stall market!
DC is easily done with a couple of diodes, but DCC needs the chip (encoder) to interpret the signals to that specific train's direction command.
You could use the engine decoder, but would need wiring down the coaches and connecters between them!
So it's easier to fit a second encoder (cheap one) in the dummy and give it an identical address as the engine (so they both get the same commands), mind that does mean the dummy needs its own pickups!

Missed that!

So by using 2 Decoders with the same address and changing CV29. I see.
I can't remember if that's one of the few CV's I can change on the Bachmann E-Z controller. I'll look into it.
It may be time to upgrade my DCC system.....if I had the money

Would the headlights need to be bi-coloured white/red LED's or 2 actual bulbs/LED's?
Thanks
End2end

[Bufferstop]

Two LEDs keeps it simpler, bicolours get you involved in different voltages.

[End2end]

Would a bi-colour LED be possible though if there is not enough space for 2 LED's?
Perhaps something along the lines of these? https://www.ebay.co.uk/itm/4-X-OSRWPA7K ... SwyP5aOVkL
Or these https://www.ebay.co.uk/itm/4-X-OSRMPA7K ... .l4275.c10
Thanks
End2end

[Bufferstop]

I don't know how you would control a bicolour LED with the output from a decoder. The applications of them that I have seen do it by changing the voltage applied. We have them in huge clusters in outdoor lights on the Riverside. An inverter in the lamp base cycles the voltage up and down so that they continually change colour. I've seen a bigger system at Media City where all of the lights are powered from a huge installation behind the car park. They all change colour in sync. I'll see if I can find a circuit for a single LED.

[End2end]

The applications of them that I have seen do it by changing the voltage applied.

Are the tri-legged LED's (I linked to above) not changed by sending power down one leg or the other instead of changing voltage like (I would imagine) thier 2 leg / bi-colour counterparts?
Thanks
End2end

[Peterm]

Yes. A three leg led with the common positive being the middle one. Each leg having it's own appropriate value resistor.

[Peterm]

Yes. A three leg led with the common positive being the middle one. Each leg having it's own appropriate value resistor.

Quick edit to say that the two outer legs are negative to the decoder yellow, white, etc wires. The middle leg is actually the positive.

[End2end]

I was searching through my layout folder on my pc last night and had completely forgotten about these!!!
https://www.ebay.co.uk/itm/Hornby-HST-L ... 1438.l2649

Albeit more expensive but this solves the problem quickly and neatly.
Thanks
End2end

[Bufferstop]

I think multilegged LEDs and bi-colour are different beasts, bi:-colour are colour changing. Multi legged are multiple LEDs in a single package with a common lead. I think the lamp clusters on an HST power car have sufficient space for individual LEDs. If there's a problem accomodating them, there's room to house any size LEDs in the body and run single optic fibres to the lamp clusters. I don't no if Timbersurf has this in his lists, but the "mares tail" fibre optic bundles used on the 80/90s UFO table lamps contain a lifetime supply of fibres and are fairly robust.