Bi-color LED wirng help please

Model Railroader Electronics and DCC
1

Thanks in advance.

I have the following, ('m still DC, HO)

  • SPDT (on)-off-(on) toggle,for twin coil PECO turnout motors (PL-10)
  • SPST momentary push button normally open, for “which turnout is this anyway, indicator light”
  • BI-Color (red/Green) LED in “dwarf” housing L130WDT/EGW from this linked pdf http://www.smcelectronics.com/DOWNLOADS/LED03.PDF
  • more yellow 5mm LEDs than I need.
  • appropriate resistors for all LED applications

wiring the toggle to the PECO is not the problem and I will use a CDU

The puzzle I want to solve is:

I want to use the LED dwarf to indicate turnout position in a yard I’ve constructed. This yard, small though it is, has 10 turnouts and I hope to have my seven year old operating it. What I want to do is use the push button to light a yellow, non protypical, light at each turnout. BTW, The push buttion and the toggle are mounted side by side along the edge of the yard, in proximity to the trun out. the whole yard is 9’ and is along the near edge of the layout.

Question: using a spare track power transformer/power pack, (how) can I power the red/green portion of the dwarf on the DC side, and via the push button, the yellow “combined” aspect on the LED? Keeping in mind that the red or green will always be burning depending on the turnout setting. I’ve read here and elsewhere that AC will do that, but is there an alternative, and how is that hooked up, espically in light of (no pun intended) the red/green always on, situation?

The point is that the son and his old man would like to be able to press the push button before or after setting the turnout. That way he/we can tell which turnout in the maze we are dealing with. (This would also prevent the look from being too un-prototypical unless we’re

2

Does the Peco PL-10 switch machine have aux contacts on them to control lights or LED’s?

3

Would it not be easier (and maybe less confusing) to make a operating panel with a DIAGRAM of the yard drawn on it, and put the toggle switch for each track switch right at the proper place on the diagram? So if you (or he) want to throw “Switch #4” in the yard, you just look for “Switch #4” on the diagram – and there you are.

/Lone

4

gandydancer19, there is an addon (already in place) which provides the requisite contacts.

lonewoof, yes it would, that being the case, I did something else entirely. Typical of me. What you describe is what I did on the main part of the layout, The yard was built, something as an expirement, as modules on the front of the existing layout. So, simpler yes, but that is not what I’m dealing with, that is the die is already cast, that ship has sailed etc.

Thanks for the answers, again I guess my main interest is how do I hook up the bi-color LED to get yellow. + and - off the AC side of the power pack, to the outside two legs of the three leg LED, i.e. niether to the common? And what of the DC power already running through either the red or the green sides/LEDs.

Roy

5

AH! I see what you are trying to do now…

With a two lead bicolor LED you could do something like you are thinking. A two lead bicolor is like two leds, with the opposite sides of each LED going to the two leads. A three lead bicolor is like two LEDs, with the commons tied togeter. So, with a two lead bicolor, AC will give you yellow. With a three lead, I think you’ll want to activate both LEDs at the same time to get yellow. That shouldn’t be too hard, if you need help, I’ll try to put a few more brain cells into it.

6

I could help you if you want to use the bi-color LED AND a yellow LED. Since Jeff knows how to make yellow with the three lead bi-color LED, I will let him run with it.

7

This is a great question Roy!

Off the top of my head with a DPDT MOM/ON switch.

this is because you should not have both the AC and DC supplies conencted to the same place at the same time or they will interact - probably not nicely.

Ctr of LED to ground,

Ctr switch contacts one each to each end of LED (through resistor).

MOM outside contacts of switch to AC

ON outside contacts of switch (one only) to +Vcc

Select which terminal gets + through your aux switch machine contacts.

There may be a more elegant solution of course

(Diode routing perhaps? - need to think on it).

Karl

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Jeff Karl, Gandydancer and all, thanks

Jeff you nailed it, that worked great. I see a few evenings under the magnifying glass.

to review, forget AC, not required.

Center of the bi-Color gets (-) and the resistor

one side gets black wire and a yellow (red, yellow, green, and black are my standard wire colors for this situation, conveniently found inside the 6’ telephone wire I have absolutly no use for. The reason I got into model railroading is to use up all that useless stuff, LOL)

other side gets red wire and a yellow

red and black go to (come from) the relay (PL 13) on the Peco and gets the (+) side from there going to either the Red or the Green LED inside the bi-color

both yellows go to the posts on the SPST push button normally open momentary.

the LED burns red or green as appropriate until the push button is pushed and closed, tying the red and green feeds to the LED together and producing a sort of an orange. The color of orange is not an issue, just so it changes from red or green to something other than red or green.

So as a car is rolling down my Simulated hump (actually the yard is about 1/2 below the grade of the main its comming off of) I can press the push button beside the toggle I think I want to throw and confirm, 1) that its the one I think it is, and 2) throw it, if the tank car on the hump is now fixing to roll into the passenger terminal.

All joking aside, thanks for your input, as always, it does not take long to get useful information for this forum, (as well as perhaps some not so useful information, (for the current project of course), but always information that is filed away somewhere for future use.)

I love it.

Roypea

9

I’m glad I could help!

Once I figured out what you were doing, it hit me over the head! The trick is that there are two lead and three lead bicolor LEDs, and the way you would do it is different. Anyway, I’m glad to hear that it works!

10

I’m not familiar with the Peco switch machines, so this schematic is drawn as if it were a Switchmaster turnout motor.

This is an alternative option. Instead of using a PBNO (push button normally open), get a PBNC (push button normally closed). A PBNC will keep the circuit intact, but will open the circuit when pressed. Tying such a button in series with the cathode of the LEDs will in effect turn them OFF when the button is pressed. So this way you will be looking for which LEDs turn off rather than which one turns yellow.

With your method of tying both anodes together with a normally open pushbutton, be careful that you’re not shorting anything out from the relay side. The way my schematic is drawn, a pushbutton across the anodes of the LEDs would short the power supply. But Peco may be different.

EDIT: Removed my first schematic and explanation as I didn’t read the solution posted above carefully enough.

EDIT 2: Clarified schematic is drawn for switchmaster, added caution about shorting power supply.