A Railroad with Relevance

Module #13 delayed

Written By: Alan - Apr• 10•16

I got off to a great startmodule 13 on module 13 only to be stopped dead in my tracks. Ha ha no pun intended. Long ago I was contacted by a Model Railroad Hobbyist reader asking if I would sell him a few of my occupancy detectors for his dead rail railroad. At the time I had an inventory of over 30 units so I said sure, figuring I could build a lot of modules before I used up what I had. I could make some more in the mean time. Well, you know what happened, don’t you? I didn’t make more. Building module 13 I opened the circuits box to find I was down to my last four. Module 13 needs six. Full stop.

Time to etch, drill, and solder more detector boards. Luckily, I saved the original PCB mask transparency and on-hand were all the components with one exception – the screw terminal strips.

So, module 13 construction is on hold while I await the arrival of terminal strips.

Track is laid, switch machine installed, and power bus poles are in place.


The board etching came out nice!


I’ll be back just as soon as I make a few more of these (on the left).



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  1. rob dove says:

    That is kinda funny Alan. I seem to remember some entries a while back when you were mass producing these things or it might have been similar items so you would have all you needed and some spares! Funny, how one thing leads to another and you end up not having enough on hand even when you planned for spares so you could quickly replace any components that failed.

    I am sure this will only be a set back of minor proportions that you will quickly get past. It is great to keep getting notifications regarding your updates so I can follow along with the progress.

  2. Jeff says:

    Ballpark cost estimate for making these boards from scratch? Just components, not etching supplies.

    Reading your other posts I must have missed you mentioning how you came up with the designs for the boards. Either you found the schematic plans somewhere, you are poster boy for an electronics nerd, or you are an electrical engineer! Regardless, I am in awe of the electrical side of your layout.

    Eventually when you get to the point of throwing the master switch on the entire layout and powering everything up to operating voltage, I’ll be curious to see how much power this thing draws from your house grid, to include lighting.

  3. alan says:

    terminal strip 1 @ 1.28 = $1.28
    power diode 3 @ 0.21 = $0.63
    ic socket 2 @ 0.12 = $0.24
    timer ic 1 @ 0.09 = $0.09
    optoisolator ic 1 @ 0.27 = $0.27
    resistor 6 @ 0.01 = $0.06
    elect cap 2 @ 0.14 = $0.28
    cer cap 1 @ 0.01 = $0.01
    sig diode 1 @ 0.01 = $0.01
    led 1 @ 0.10 = $0.10

    total: $2.97

    1 UV 8×12 board @23.45 = 20 circuits = $1.17 ea

    grand total $4.14 per detector

    Yes, it is my own circuit design.

  4. alan says:

    The lighting is the real power consumption. All of the electronics gizmos are milliamp devices.

  5. Ron Ventura says:

    Hi Alan,

    I have been following your blog since I discovered it about six months ago. I’ve read every post and am in awe of your workmanship and attention to detail. I look forward to each new post. Your page is permanently open in a tab in my browser, and I check it just about every day, in the hope that there’s something new.
    Just recently though, something has happened to your blog. The back and forward arrows have swapped positions, so the forward arrow is on the left and the back arrow is on the right. I don’t know why, but this is doing my head in. I use the presence of the forward arrow as a telltale that there’s something new to look at on your blog. I’m slowly retraining my brain to the new position of the arrows. Do you know what happened? Really off topic I know, but it’s got me intrigued for some reason.
    Back to more important stuff: keep up the amazing work on your layout. It’s a high water mark in design and construction for home layouts.

    Ron Ventura

  6. Alan says:

    Ron, very astute observation. A recent theme update has jumbled the site operation. Apparently it doesn’t play well with some of the WordPress plugins (nav arrows). There are other issues too. When I get time I’ll dig into the code to see what went wonky.

  7. Ron Ventura says:

    Hi Alan.

    If it’s a choice between doing more on the layout and fixing the navigation arrows, definitely go for the layout. I can adjust.

  8. Alan says:

    Hey Ron, got the nav arrows fixed for ya.

  9. Ron Ventura says:

    Thanks Alan. I can sleep again. 👍

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