Lighting with an Digitrax DN 163 AO

[woodone]

I have a Atlas N scale H-16-44 loco. Using a DN 163 AO decoder. The original light board had two LED’s at each end.
One was a dual color- red/green. When running one direction with H/L on the end with the H/L on the marker lights would be green- the other end the H/L was off but the markers would be red- reverse direction and they would just be reversed on each end. The dual color LED’s are commen cathode .
I want to make that happen using the DN 163 AO.
I can remap cv’s 35,36 and 37 but cv38 can’t work in the FOr mode.
I think that I
will have to change out the bi-colored LED’s to a commen anoid  type.
Still not sure that is going to work.
Any ideas or help on this?
Thanks

[peteski]

It took me a while to figure out what you were describing, but I think I understand now.    So the original DC light board has common-cathode bi-color LEDs, correct?

That would make sense as common-cathode bi-color LEDs are the most common type. To be honest I don't think I have seen a 3-pin bi-color LED which  had common-anode configuration.  But they probably do exist.

You are also correct that since DCC functions use a common positive (blue wire), if a bi-color LED was to be activated by a decoder, it would have to be common-anode type.   But how about replacing the original 3-lead LED with 2 small discrete SMD LEDs (red and green)?  Or get a bi-color SMD LED which has 4 pads (so you can wire it either way)?

BTW, green marker lights are not usually used on trains.  Replacing green with white would make more sense.  I believe that red/white SMD LEDs are available (with 4-pad configuration).

[carlso]

Sir Pete,

Me thinks you need to review your facts regarding flag or class lights on a locomotive. Yes, green was used on the head end.

On the SP:

White flag indicated an extra train not listed in the time table.

Green flag was used to indicate that there was more sections of a train to follow. I know that, especially during WWII, during heavy troop train movements they would have several sections of a train.

Carl

[peteski]

Sir Pete,

Me thinks you need to review your facts regarding flag or class lights on a locomotive. Yes, green was used on the head end.

On the SP:

White flag indicated an extra train not listed in the time table.

Green flag was used to indicate that there was more sections of a train to follow. I know that, especially during WWII, during heavy troop train movements they would have several sections of a train.

Carl

I should have elaborated more. I am well aware of the class flags and lights usage.  But how many times do you run run multi-section trains during your ops sessions?  If you do then by all means, use green markers. But for great majority of model RR operations (On most layouts) these would be white.

That particular model is only capable of displaying green or red markers - that (green) for most model operations is not very realistic, (since as you correctly indicated, there should always be another section to follow any train operated by that model)..

[woodone]

I have no idea has how the prototypes would work nor there use. The loco is a unit that belongs to a customer. This is how he would like the lights to work. Just as it came new .
Pete- yes the 2 bi-colored LEDs are commen cathode.  1 at each end. There is a separate H/L at each end. I have found bi-colored LEDs with a commen anode. My delima is to get the marker/class lights to follow the H/L’s.
BTW the bi-colored LED’s are shielded from the H/L’s
The decoder does not allow me to use F4 function to work with the FOr my remapping.
My thoughts right now are to wire the bi-LEDs in series with the H/L’s.
That way when you have the H/L’s, on the marker/class lights would follow.
One direction the colored LED’s would be corectt- reverse direction they would also switch.

[peteski]

I'm not sure if I understand it again.  Do you want both green (in the travel direction) and red (in the rear) to be tied to the headlights?

If yes, then I wire the headlight output to the headlight (with its own resistor), and also run the same output to the green cathode on the headlight side and to the red cathode on the rear side. Then put resistors on anode side of each bi-color LED.  Repeat the hookup for the other direction.  That way you can independently adjust the brightness of the headlight and marker lights (as I suspect that the white Headlight LEDs will need much lower current than the red and green LED chips.

[woodone]

I am not doing a good job of describing what I need to happen.
When moving forward- headlight on, the forward markers would show green while at the same time the red markers at the rear would be on.
When you reverse directions they would switch, H/L now on at rear, with the rear markers showing green, while front markers showing red. H/L at front is off.
Hope that clears things up.
Thanks for the input.

[jagged ben]

To go back to your original post...

Peteski's instructions will work for the common anode type, which means switching out the type of LED.

However you should be able to use the common cathode type by just switching 'anode' and 'cathode' in his instructions.
[edited:  see comment below]

I'm not sure I believe you that the fourth function (CV38) can't work the way you want.  You didn't say if you tried wiring this up yet.  If you have, perhaps we just need to help you with CVs.   Or does the customer not want to ever have to check functions other than F0?

[jagged ben]

To elaborate on the last paragraph of my last post..

If you have already wired the red and green to the four extra function outputs, you would remap those functions to F0F and F0R by adding value to CVs 33 and 34.  CVs 35-38 get set to zero.

[jagged ben]

If you have wired the reds and greens to the F1-F4 outputs, then you program CVs 51-54 to 40 or 50, respectively, to be on in forward or reverse when F0 is on.  This is separate from function remapping.

Of course Decoder Pro would do all the CV figuring for you.

[peteski]

I am not doing a good job of describing what I need to happen.
When moving forward- headlight on, the forward markers would show green while at the same time the red markers at the rear would be on.
When you reverse directions they would switch, H/L now on at rear, with the rear markers showing green, while front markers showing red. H/L at front is off.
Hope that clears things up.
Thanks for the input.

Looks  like I understood you correctly (even thought we seem nto to be communicating things clearly).  What I described in my last post will do that with common anode LEDs.  I can draw you a diagram if it will help.

Jagged Ben says that it will work with common-cathode LEDs. I don't see how it would.

EDIT:
Here is the diagram. It will work the way you describe it.
The headlight resistor can be placed on either the cathode, or the anode side, but since the red/green marker LEDs share the same resistor, it has to be on the anode side.  In my experience white LEDs use much less current than red/green, so having separate resistors (to adjust the brightness) is desirable.  If you want to go further and control brightness of each color, then hook the blue wire directly up to the anode of the marker LED, then install resistors on each cathode lead of the LED.

[jagged ben]

Jagged Ben says that it will work with common-cathode LEDs. I don't see how it would.

You are right.  I was thinking really simply and overlooking that the polarity of the decoder's function outputs is not configurable.  Post edited above.

[peteski]

You are right.  I was thinking really simply and overlooking that the polarity of the decoder's function outputs is not configurable.  Post edited above.

Diagram added to my earlier post.

[woodone]

Pete, that is what I have in mind to do.  Waiting on the new LEDs to show up.

[woodone]

Opps-  forgot to thank you for the diagram Peteski.