I had to test my new workbench, so decided to see how buildable a simple signal would be. I guess I should warn you of the poor graphics and photography.

The plan:
Making use of the directionality of LEDs, one needs only two wires to have two leds light up in two different ways, by changing polarity. As building in N makes it difficult to hide unnecessary wiring, this seems like a good thing. LEDs have the nice tendency to come with legs which could double as a post to put the signal on, they are a bit on the short side, but I guess they could be repaced by brass rod without too much trouble. As these signals are mostly for testing and practising purposes, I didn't worry about that. Also the bottom LED is sunnywhite (too bright, too) and not green as it should. The two posts are connected with bits of styrene rod which especially after painting hides the fact that they are only pieces of the LED.
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Here proof that the signals work. Also proof that they are a bit too short next to the coach.
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I had some similar scrathbuilt signals on my last n-gauge layout, they are indeed very fiddly to build. I got some 1.6mm x 0.8mm LEDs, a pair soldered such that when the polarity was one way it was green, and when it was the other it was red. I also managed a 4-LED model which allows independent control of all 4 LEDs. I plan to make 15 more for my new layout.

Streetlights can be made in a similar way.

looks good. What size LEDs did you use ?

Looks good. Another consideration for wiring would be to use the wire from an old transformer. I unwrapped it carefully, then soldered it to the LEDS, then carefully ran them down the sides of the post I mounted my scratchbuilt traffic signals on.

TCWORLD Wrote:I had some similar scrathbuilt signals on my last n-gauge layout, they are indeed very fiddly to build. I got some 1.6mm x 0.8mm LEDs, a pair soldered such that when the polarity was one way it was green, and when it was the other it was red. I also managed a 4-LED model which allows independent control of all 4 LEDs. I plan to make 15 more for my new layout.

I used the exact same principle here. I gave some thought to how to make 3 or 4 LED signals, but it seems one would need a bit more wiring for that. Did you come up with any tricks to keep the number of wires to a minimum? I can't think of less than 5 wires for a 4 LED signal.

Transformer wire seems indeed to be useful for these things (and smaller modeling projects in general..)

The LEDs are 1,8mm sized (that's what they are listed as) They have a 3x2x2mm box underneath and a 1,8mm diameter bulb on top. Which makes them approximately correctly sized for use in N as is.

Yes, there are 5 wires. I found a site where you can get very thin walled tubem anMagnet wire, which means that you can fit up to 7 wires in a tube. Whic means my next planned signals with 4 aspects, but which have multiple grounds are possible.

They also sell the tiny LEDs. I'll find a link out for you.