Do you need some bicoor LEDs ?

I have some extra ones with 3 wires.  What size?  How many?  Let me know and I'll look.

Thanks.

Thanks, but no.

I had used my last common anode bicolor on the panel and didn't want to buy a quantity from Digikey. My local source is a place called Qkits here in Kingston and they didn't have any of the specific flavor I needed. So I switched to red and green (had lots of those anyhow). The layout and information content of the panel is finally stabilizing (think I have thought that 2 or 3 times so far...sigh).

I have a sack of 3mm bicolor that I can use for signals but not the panel -- DTM30 will only use common anode format, but the same vendors signal logic card SIGM20 will use either. The signal displays on the panel are relay cells in the DTM30 that echo the states of the signal processor. 

Signals are so cool

I've built a lot of them in all scales over the years.  I'm really looking forward to each new post you do.  Best wishes.

Wow looks a little complex

Wow looks a little complex

Its my Railroad...

There are occasions when I look at my layout and ask myself WTF... Yes, for a tiny railroad on a 7x10 footprint it is probably way more complicated than any rational person would do. But it is my retirement project and I have, so far, invested five years of work in it. This includes a couple of rip it out and redo it moments -- adding complexity to the trackage and restructuring the electrical plumbing. Someday I will let my grandkids run trains on it. But I am having fun... and am learning all the time. And since I have no deliverables to anyone other than myself it makes a nice activity when it is too cold to work in the woodship, too wet to garden or too cloudy to look at the stars. And this is my 3rd run at a control panel -- immer besser, I hope. But who cares...

I like Complex!

I like where you are heading with your panel and wiring.  Complex is good if that's what you like.  I do like it and will be following your progress.

Once you have it the way you like it, will you make wire wrap connections permanent soldered connections?

Follow on Note

I am debating whether to solder them or not. The shortcoming of this approach is that the wirewrap to the LEDs is directly around their trimmed leads. I have solder tacked one lead of the LED to retain the thing. Issue I have run into is that the quality of commercial LEDs from the local electronics distributors is variable. And I have had a couple that failed after a few hours of operation. Unwrapping them, even if I have to replace the entire connecting wire, is trivial. And the one real shortcoming of wirewrap is that the 30 gauge wire can break when reused and still look ok. Soldering doesn't really help -- it makes it harder. A solder joint where the wire goes through the board is easy to undo with a solder sucker or braid. When it is wire wrapped around a lead to a heat-sensitive LED its a bit tougher.

What I would have liked to have done would have been to use sockets for all the LEDs -- then dealing with failure or the 'nuts' moment when you realize that the red/green signals to your bicolor LED were actually green/red and you have to flip them around. Proper LED sockets that I found online were pretty expensive -- $5.00 each or so. I have experimented with using header pin sockets but am not happy with the retention of the trimmed LED leads. That sort of socket also added more thickness to the assembly that cause its own problems.

If I were to do it all over again I would get a custom PCB board made and solder everything to it. But wire wrap has not been difficult to do -- as long as the board is marked and conventions followed as to LED orientation. And it did allow the design to evolve -- would not be so easy with a PCB. 

In the lower right of the picture are two orientation arrows showing the direction LEDs must be inserted. The long lead is always down for vertical and to the right for horizontal. The grey objects are the IDC connectors that I used to connect the board to the DTM30 controllers. The connectors are numbered on the shell and the board. And the first and last pin on each is also numbered. Each connection is documented in a planning sheet that includes the DTM cell and layout addressing that drives it. So tracing anything is pretty simple.

I envy the folks who have space for 28'x32' layouts and can afford space for a full sized Union CTC panel. I have no such luxuries. The layout is 7x10 and must be movable. Makes for some interesting challenges.

Slack

I've found that wrapped wire is not reliable directly on LED leads. Something to do with the material of the lead, I think. All I do now is put a simple two turn loop around the lead and solder it. The loop of wire will pop loose easily when you reheat it, and it can easily be pushed over the replacement. Just leave the wire slack enough to pull off the leads.

pqe

Wrapping tool?

So far that hasn't been a problem. I am using a wire wrap tool that I originally bought to configure boards on my PDP-11/23. Yes, I have had it for a long time. The stripped end of the 30 gauge insulated wire is slid into a slot in the tool and slid over the post. Holding the other end of the wire steady I rotate the tool, which drags the wire around the post. This ensures that there is slack and if need be a fresh end can be cut without having to replace the entire wire. This gives me typically 4-5 turns around the lead -- they can be unwrapped but will not slide on the post. Looking at the post there are small dents on the corners from the wire -- this stuff is softer than the wire wrap posts normally used for prototyping. I have been able to use the tool to start unwrapping a connection but usually it takes a fine needle nose pliers. And without my magnifier I would be blind. As an aside, I have tried this technique with heavier gage wire and  it doesn't work as well -- but heavier stuff also doesn't fit nicely in the wiring pencil.

I have a couple of those too

The theory is that the corner of the square posts will cut into the Kynar wire to create an oxygen free joint. That tool is small, but exerts an amazing amount of pressure. I'm still using some circuits I built in the 70's using that technique. It's fast and let me build circuits of very high density. (This was important back in the days of nickel logic, where you had a chip for what is now done in one line of arduino code.)

My bad luck with LEDs might have been related to a particular brand. Probably the leads were too soft to cut into the wire.

I also made circuits with a wire-wrap pencil, which uses 36 awg wire with a solder through insulation. The wire was wrapped and soldered directly to the pins of the ICs. Amazingly, those still work too!

I gave up both techniques when I started building things someone else might have to repair, and my eyesight is not up to them even with a magnifying glass.

pqe

Oldie but Goodie

Thanks. Sorry to hear about the eyes. It makes some of this close in work more challenging than it should be. I am able to work with my magnifying visor - mandatory with pretty much anything I do for the railroad. Glad to hear you are an old pro with the technique. I don't expect anyone to work on this so maintainability by others is just not a concern.

g