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Anyone know of a DCC switch?

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  • Member since
    August 2017
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Anyone know of a DCC switch?
Posted by Gary Morton on Thursday, June 25, 2020 5:44 PM

I'm considering adding lighting to a number of passenger cars. To avoid installing pickups on all cars, I'd like to use a battery in the first car in a consist, and cable to the other cars (these consists will rarely be broken up). But would also like to be able to turn the lights on and off, or even bright/dim/off, from the DCC throttle. I'd then have to install a pickup on only that first car.

Anyone know of a simple, 2- or 3-way DCC switch with programmable addressing that will accomplish that? 

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Posted by richg1998 on Thursday, June 25, 2020 6:28 PM

Right now, the only DCC switch that I know of is a lighting only decoder. There might be new DCC inventions that I am not aware of.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

  • Member since
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  • From: Bakersfield, CA 93308
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Posted by RR_Mel on Thursday, June 25, 2020 7:28 PM

I operate my passengers consists exactly like what you posted.

https://melvineperry.blogspot.com/2018/03/march-18-2018-sp-heavy-weights.html

I power the lighting from a baggage car using a function only decoder to turn on and off the lighting.  You can also use a locomotive DCC function to control the lighting.



As I run dual mode (DC or DCC) I also use a latching reed switch in the baggage cars to operate the lights when operating on DC.

The Lithium AA size battery is charged from track power.  You can see the reed switch attached to the roof.

If you want more info send me a message through the Forum mail and we can trade personal email addresses.  More than happy to be of help.

I might add in almost 4 years I’ve never had even one problem with my heavyweight or streamlined passenger consist. 

Mel



 
My Model Railroad  
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 

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Posted by MisterBeasley on Thursday, June 25, 2020 8:40 PM

It's a bit more work, but putting pickups in all the cars and connecting the power lines together will give more consistent power to the lighting and reduce flickering.

It takes an iron man to play with a toy iron horse. 

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Posted by RR_Mel on Thursday, June 25, 2020 9:36 PM

 

My system can’t flicker and only uses the baggage car for power pickup.  The 4 volt Lithium AA battery will supply full power to all 12 cars of my passenger consists for over 80 hours.  The onboard charger keeps the battery topped off from track power.

Like the op I hardly ever uncouple my passenger consists so the wires between cars isn’t a problem.  Having the ability to control the lighting on/off by DCC F4 function works great.  Having the onboard batter lets me park my passenger consists without track power and the lighting on for hours.

All 13 cars (including the baggage car) only draws 60ma to power the LEDs.  They could be powered from the locomotive and not need power pickup from the baggage car.  A DCC decoder could power the lighting to all cars.


Mel



 
My Model Railroad  
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 

 

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Posted by rrinker on Friday, June 26, 2020 8:18 AM

 The simplest way is to use batteries to power the lights - never flickers then - and use a DCC function decoder to operate a small relay to connect the battery power to the lights.

                                       --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by RR_Mel on Friday, June 26, 2020 10:12 AM

I use a small 5 volt relay with resistors in series with the coil.  I stock both SPDT and DPDT 5 volt relays for switching from my Arduinos and either a 6volt 50ma bulb or a pair of 270Ω ¼ watt resistors drop the decoder voltage to the 5 volt relay.



The above schematic is the wiring of my Heavy Weight Baggage car.  I powers the lighting in 11 cars easily.

I think if I was building up a power car now I would try Randys idea using a mini DC to DC converter instead of the 7805 regulator.  I only have two passenger consists and both work great so as they arn't broke I'm not going to fix them.



Mel


 
My Model Railroad  
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 

  • Member since
    February 2002
  • From: Reading, PA
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Posted by rrinker on Friday, June 26, 2020 6:54 PM

 You probably should put a small diode anti-parallel with the relay coil to keep the BEMF when the coil lets go from damaging the decoder.

 I just have little glass 1N4148's on my turnout controller relays.

                                      --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
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Posted by Gary Morton on Friday, June 26, 2020 10:38 PM

Mel . . .

 

Thanks! That is extremely helpful. I may take you up on the email offer if I run into any problems.

---Gary

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Posted by Overmod on Friday, June 26, 2020 11:29 PM

RR_Mel
As I run dual mode (DC or DCC) I also use a latching reed switch in the baggage cars to operate the lights when operating on DC.

Mel, I know this is probably clear enough, but you might want to mention that you work the latching reed switch with an external magnet on a stick or similar arrangement, like a toggling on-off manual switch with no external access but easily and reliably worked by placing the magnet over an easily-accessed 'standard part' of the car when it is on the layout.  It is interesting to consider the wiring that lets this work on DC while preserving addressable on and off (including an 'all-on' as in the old X-10 light controls) using what is probably going to be an overlay on 'standard' DCC CV assignment to somewhat customized hardware.

I am tempted to say that implementing complicated individual lighting control with IoT device addressing and control with a wireless radio protocol is likely a far better solution with far better/cheaper aftermarket and even OTS support than tinkering with decoders to make them less than fully compliant with a decades-old set of DCC standards...

  • Member since
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Posted by RR_Mel on Saturday, June 27, 2020 11:53 AM

Randy

I did use a 1N4148 with the relay just forgot to include it in my drawing.  Thanks, I’ll redo my drawing and replace the one in the above post.

I like your idea Randy!!!!



I found this little goody this morning, I have 5 on the way.

https://www.ebay.com/itm/1-2-5-Mini-DC-DC-12-24V-To-5V-3A-Adjustable-Step-Down-Module-Buck-Converter/233290585272?ssPageName=STRK%3AMEBIDX%3AIT&var=532794719110&_trksid=p2057872.m2749.l2649


Overmod

Actually it’s very simple and cheap using the Digitrax Function Decoder, $14 decoder and use the locomotive DCC address for function 4.

I use the Digitrax Function Decoders often, they work great for the backup light control on my Daylight Observation car too.



Thanks for explaining the reed switch operation, my bad.


Mel


 
My Model Railroad  
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 

  • Member since
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  • From: lavale, md
  • 4,678 posts
Posted by gregc on Saturday, June 27, 2020 12:45 PM

Gary Morton
But would also like to be able to turn the lights on and off, or even bright/dim/off, from the DCC throttle.

why?

someone once asked how bright the lights of a passenger car should be and it was suggested that only bright enough to notice them when it darker out.

i've noticed lighted passenger cars in coach yards overnight

greg - Philadelphia & Reading / Reading

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