# LED Control Board



## tmiller (Jan 15, 2011)

Greetings,

I am just 2 weeks into HO, and having a ball. My question is how do I make a simple control board using LED's to show when a turnout is thrown. Probably a red when turned and another one green when straight. Or simply one that shows red when thrown. Either way will work for me.

I am using the Bachman turnouts with the small slide switch that is included in the pack. I will be using a MRC DCC Prodigy Express system.

My knowledge of electronic circuitry is very limited, and I do best with visual explanations.

Any help would be appreciated.

Thanks.


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## T-Man (May 16, 2008)

Welcome to MTF.

You would think there is a simple solution, but id there was it would come with the switch.

The motor or coil for your switch is AC. 
You can use a relay but it uses DC.
Maybe other members have solved this. A mechanical switch would be enough if you are clever enough to attach it.
You can also go with Train detection by using a light sensor or a reed switch. The reeed needs a magnet on the train to activate it.

Getting more complicated is the capacitor discharge system. Takists has one for his layout with the control board. 
Maybe you can convert to DC motor and have the DCC run the switch. The electronics board may have indicator lights.

That's a brief outline.
So look for train detection, tortoise motors, capacitor discharge system, your DCC manual on switch control.


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## gc53dfgc (Apr 13, 2010)

T-man you know that DCC uses AC power not DC right?


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## nsr_civic (Jun 21, 2010)

Nope. DCC is not AC it is DC with varying square wave patterns in the voltage. the only type of train that uses AC is O scale and S if im not mistaken.


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## NIMT (Jan 6, 2011)

Was your questions was how to drive LED's either on control board or your layout with using a bachman switch.
This can be acomplished in alot of differnt ways. Sorry to say there is no easy answer to this.
One option there is a snap relay that atlas makes that would drive the switch motor and the LED'S at the same time. 
It's Atlas Item# 200
http://www.atlasrr.com/Images/Track/Trackphotos/200.gif
Another option is this one for the control panel lighting.
http://www.atlasrr.com/trackmisc/57switchcontrol.htm
Please also read a new post in the DCC Forum on DCC HELP!


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## T-Man (May 16, 2008)

I think it's AC for O scale but it may depend on the manufacturer.
Now, I withdraw from DCC questions. The layouts I see all use Digitrax in HO and N.


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## gc53dfgc (Apr 13, 2010)

nsr_civic said:


> Nope. DCC is not AC it is DC with varying square wave patterns in the voltage. the only type of train that uses AC is O scale and S if im not mistaken.


http://www.loystoys.com/info/how-dcc-works.html

According to this your wrong. The command station or booster sends square wave AC signals through the rails and the decoder inside the engine changes it from AC to DC to run the motor.

More specifically in DCC Basics on the page number 1


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## gunrunnerjohn (Nov 10, 2010)

T-Man said:


> I think it's AC for O scale but it may depend on the manufacturer.
> Now, I withdraw from DCC questions. The layouts I see all use Digitrax in HO and N.


Well, it's certainly A/C for O-scale, you connect your transformer directly to the tracks!


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## gunrunnerjohn (Nov 10, 2010)

I looked at that reference, it appears they encode the DCC directly into the power, TMCC/Legacy uses radio signals and doesn't actually try to send it down the track.


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## gc53dfgc (Apr 13, 2010)

gunrunnerjohn said:


> I looked at that reference, it appears they encode the DCC directly into the power, TMCC/Legacy uses radio signals and doesn't actually try to send it down the track.


correct me if I am wrong aren't TMCC and Legacy control systems for O scale right? DCC is similar to the TMCC and Legacy instead of the decoder recieveing its signals from the radio, the command station sends constant AC generally 12 to 16 volts through the tracks and the decoder picks up very slight and quick variations in the AC signal and transforms the AC to DC power that the engine runs off of. This is also how the other features like lights and sound are controlled. DCC is in a way the equivilant to a real life overhead or third rail system except without the overhead wires and the third rail.


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## RGC (Dec 11, 2010)

nsr_civic said:


> Nope. DCC is not AC it is DC with varying square wave patterns in the voltage. the only type of train that uses AC is O scale and S if im not mistaken.


DCC is AC.

http://tonystrains.com/tonystips/dccprimer/intro/dcc-basic-principles.htm

"BASIC PRINCIPLES

• The power on the tracks is alternating current (AC), and not DC or direct current. "


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## gunrunnerjohn (Nov 10, 2010)

Correct, I was just pointing out the differences between TMCC/Legacy and how HO/N scale DCC functions. Sorry if I was confusing.


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## tankist (Jun 11, 2009)

guys, discussion is not about AD/DC


tmiller said:


> Greetings,
> 
> I am just 2 weeks into HO, and having a ball. My question is how do I make a simple control board using LED's to show when a turnout is thrown. Probably a red when turned and another one green when straight. Or simply one that shows red when thrown. Either way will work for me.


my approach is shown here 

and quick youtube vid of it in action


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## tankist (Jun 11, 2009)

NIMT.COM said:


> Was your questions was how to drive LED's either on control board or your layout with using a bachman switch.
> This can be acomplished in alot of differnt ways. Sorry to say there is no easy answer to this.
> One option there is a snap relay that atlas makes that would drive the switch motor and the LED'S at the same time.
> It's Atlas Item# 200
> ...


i haven't seen this Atlas switch control yet. wow, what an ugly, uninviting piece of hardware.


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## gunrunnerjohn (Nov 10, 2010)

I have to agree, that Atlas switch control is a real dog!


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## gc53dfgc (Apr 13, 2010)

tankist said:


> guys, discussion is not about AD/DC
> 
> 
> my approach is shown here
> ...


thats a neat setup you have there. My question is how does the board know to change from a red to a green light when the point is set for strainght?


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## gunrunnerjohn (Nov 10, 2010)

What are the two green lights for? I see one is switch position, what's the other one?


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## gc53dfgc (Apr 13, 2010)

gunrunnerjohn said:


> What are the two green lights for? I see one is switch position, what's the other one?


I would believe thats for if the turnout is getting power and or to show the position when he has it set to program and is pre programming the thing.


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## gunrunnerjohn (Nov 10, 2010)

Well, I was curious as to the actual explanation of them.


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## Bucklaew (Oct 7, 2010)

After reading this whole thread, I was scratching my head and wondering if I was going at this switch business all wrong. I hate the switches that come with the turnouts/switches. That being said, I was of the opinion that they were positive throw switches (when thrown one way or the other positive contact is made and held) wrong. In fact they are momentary on switches. The reason I had a hate for them is because the el cheepo way they are built. I finally broke down and decided to break one open and probably destroy it in the process, which I am happy to say did not happen. 

Some one said the switches are AC operated. That is categorically Wrong, they are DC operated and use up to 14 VDC to cause the switch to move in the correct direction. The fact that they apply a momentary ground at one end or the other to make the switch negates connecting an Led to the same voltage or ground. You would only get the LED to light momentarily and that is not what you want.

To go a little further a single pole double throw positive switch will cost you a switch because it will apply power continuously to the coil in the switch and burn it up after a short time. This then makes designing a led configuration just a little more complex. To bad they don't make a double pole double throw with one half a momentary on and the other half a positive connection. the only real answers is a power holding circuit controlled by the momentary on switch. I can tell you what is needed but I can not design it myself. I can fix them but I am not an engineer so maybe one of you guys who went to college could come up with something rather easy to build.


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## RGC (Dec 11, 2010)

My Bachmann turnouts operate on 12-16V AC provided by the AC terminals on a cheap DC throttle powerpack or a AC wallwart.


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## NIMT (Jan 6, 2011)

Ok save your self all the hassle and throw out / Sell on ebay all the Switch machines you have and get the tortoise ones they will do it all off of a single pole single throw switch, And there are 2 sets of contacts to run signals on the track. 















A Hare is an add on decoder to a Tortoise.
A Smail is Tortoise with a decoder built into it.


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## tankist (Jun 11, 2009)

NIMT.COM said:


> Ok save your self all the hassle and throw out / Sell on ebay all the Switch machines you have and get the tortoise ones they will do it all off of a single pole single throw switch, And there are 2 sets of contacts to run signals on the track.
> A Hare is an add on decoder to a Tortoise.
> A Smail is Tortoise with a decoder built into it.


i would almost agree. but this recomendation besides being very expencive does not fit 100% situations. ie i can not use tortoises since i also want to be able to switch by hand (and get feedback from TO position detect switches)



gc53dfgc said:


> thats a neat setup you have there. My question is how does the board know to change from a red to a green light when the point is set for strainght?





gunrunnerjohn said:


> What are the two green lights for? I see one is switch position, what's the other one?


each reporting TO's have pair of microswitched installed underneath the coil ,effectlvley creating DPDT switch that is wired as polarity reverser. i use bicolor Diodes so it is either red or green. the second diode is there for viusla effet mostly and is always green. so Green-Green is streight, Red-Green is thrown. if the train comiong from diverging direction and points are not set than signal viewed as prohibitibg Green-Red.


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## gunrunnerjohn (Nov 10, 2010)

Bucklaew said:


> Some one said the switches are AC operated. That is categorically Wrong, they are DC operated and use up to 14 VDC to cause the switch to move in the correct direction.


You need to qualify your comments, all my O-scale switches are indeed A/C powered, there is no D/C power anywhere in my layout. 

I agree, the switch controls are cheezy, my new layout will be using CK momentary switches with LED indicators.


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## tankist (Jun 11, 2009)

Bucklaew said:


> Some one said the switches are AC operated. That is categorically Wrong, they are DC operated and use up to 14 VDC to cause the switch to move in the correct direction. The fact that they apply a momentary ground at one end or the other to make the switch negates connecting an Led to the same voltage or ground. You would only get the LED to light momentarily and that is not what you want.


there is no right or wrong. coils like atlas or peco can be operated by AC as well. it is the polar kato unitrack and alike that absolutley need DC.



> To bad they don't make a double pole double throw with one half a momentary on and the other half a positive connection.


uhhmmm, yes they do. but its not really what needed here


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## NIMT (Jan 6, 2011)

Anton,
If you wire a tortoise in the last fashion with the first set of LED's on your control board they both LED's light while the switch is in transition and Green for Strait and Red for Turnout.
I do think that you have an excellent layout control and switching control system. You have a greater understanding and ability then most of us can hope for.
My choice to use tortoise switch machines over other's does cost more unusually, but saves in overall electronics to run it and wiring. If you notice it only requires that there be one control wire and one common to run the panel lighting, the signal lighting, and the turnout control. I also have 2 sets of controlled contacts like your micro switch setup to run the frog power or other ??.


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## tankist (Jun 11, 2009)

i think you misunderstood what i said. tortoise is a good, full solution. but ti doesn't work for me since it takes away the posibility to switch the turnout manually. with coils i can either push a button or flick the switch itself.

as far as my system its ok, no magic happening there. it left me to desiring more. so it is now decomissioned - working on next one and that one will be  much neater
and if i might shamlesly plug - parts of old system are up for sale here


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## NIMT (Jan 6, 2011)

Anton,
Yes I agree it is a pain in the *** to change them manually, it can be done it just takes way too much effort.


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