Control Panels

Several people asked about the control panels we had on our demos at the St. Louis RPM meet.  They are easy to make, so I figured I’d share the process.

timelock

I first read about the process used to make the control panels 20 or so years ago in the Model Railroader series published in book form as “Building the Burlington Northern RR in N Scale”.  The materials and software were different, but the basic idea is still the same.  Print off the panel artwork, sandwich between some clear plastic, drill, install.  After having made a few of these over the years, there are some tips to offer that can make the process go more smoothly.

Step 1: Artwork

The most critical part is creating the artwork.  Any drawing program can be used.  Personally, I’ve been using the free Inkscape vector drawing package.  When creating the artwork, be sure to include proper clearance around LEDs and switches to accommodate the mounting hardware you plan to use.  Also, be sure to include mounting holes in the corners.

After creating the artwork, print it out using a color printer on high-quality paper.  You will obviously need one for the actual panel, but print a couple extras to use as templates and in case the first one gets damaged.

Step 2: Plastic

The next step is to create the plastic sandwich in preparation for cutting and drilling.  I use Lexan as it is less prone to chipping and cracking and can easily be cut to size on a table saw.  Align two pieces and tape the corners with electrical tape to hold them in alignment.

0-sandwich

Next, attach the template drawing to the top.  I cut triangles in the corners to help align the drawing with the plastic underneath.

1-template

2-corners

Step 3: Drilling

Once the template is aligned, use a sharp object (an X-acto knife in this case) to mark the centers of each hole to be drilled.  Poke the center, then twist a little to make a small dimple in the surface of the plastic.

3-center

Drilling is accomplished with a drill press and bits sized for the particular hardware being used.  I used brad-point bits to make aligning the bit with the marked hole center a lot easier.

Note: In the photo below I show the artwork sandwiched between the two pieces of Lexan.  In the past, I’ve tried this with poor results.  This time, I decided to try it again, but first attach the paper to the back piece using spray adhesive.  Didn’t work.  The paper still caught on the bit, ripped, and twisted all around the hole.  I had to replace the artwork in the end.  You’re better off just drilling the plastic without the artwork in place.  The holes are already marked, so there is really no need to have the artwork there during this step.

4-drill

After drilling all the holes, align the actual artwork between the plastic pieces.  Be sure to first remove the inner protective films on the Lexan.  Once aligned and re-taped, cut out the holes.  Start by piercing the paper near the edge and then slide the knife around the hole.  Make sure to use a new (or very sharp) blade.

5-holes

Step 4: Hardware

After cutting all the holes, it is now time to install the hardware.  First remove the protective film on all sides of the plastic.  Switches and other threaded hardware can be mounted first.  This helps hold the plastic sandwich together.

6-leds

The LEDs are mounted using LED holders.  I like the ones from SparkFun.  First, insert the LED into the holder, then press the combination through the plastic.

Finishing

The only thing left to do now is to wire the panel and then mount it using the corner screw holes.  Wiring can be accomplished with point-to-point soldering (i.e. “structural solder”) on the back side.  Use the component leads as interconnect wherever possible, and don’t forget to include current limiting resistors on any LEDs.  Checking polarity often is also wise, as it is a lot easier to correct a mistake before applying the solder…

At the beginning of this post is an example of the finished TIMELOCK control panel.  Below is the panel for the Interlocking-In-A-Box.

iiab

2 thoughts on “Control Panels”

  1. Gentlemen greetings
    I have a small ambition to build an operating gated grade crossing (not aiming for the moon here) and I would like some assistance from you to help me realise my ambition.
    Let me describe my situation, I have a double track line HO that require crossing signal gates (with trains running both directions). I intend to use 2 Tomar signal crossing gates with the gates operate by a “9G Micro servo” (would consider Tortoise machines).
    Now this is my dream. The gates are activated by an IR sensor and deactivate by an IR sensor. The grade crossing of course will have flashing lights and bells (not too fussed about which sound they make possibly modern? And I will use smaller speakers).
    Now I would like advice about which parts I need to purchase and how much they will cost me. Plus I’ll be needing some wiring diagrams to help me with my small ambition and a few basic instructions will not go astray either.
    Looking forward to your assistance
    Graeme Schulz
    (P.S. Live in Australia)

    1. True prototype grade crossing signals are actually relatively difficult to implement because of the need for a pair of approach circuits and then an island circuit, complete with directional logic and the like. It’s something enough folks want that some day we’ll probably at least write an article on it, if not offer some sort of packaged product.

      That said, a reasonable approximation can be made with a couple IR sensors per track. You would basically use two CKT-IRSENSE units, spaced on each side of the grade crossing so that when either was activated, the gates have enough time to descend before the train reaches the crossing. (The time delay for each to “release” after the train passes over it can be adjusted with a resistor, and they’d need to be set so that the crossing didn’t release prematurely.) You could also add more sensors in parallel if you wanted shorter delays without the chance of the gates going

      The outputs of the IRSENSE units would then all be tied together to give a “grounded when a train detected” output. That common output could be connected to a MRServo-1 unit, tied to a pair of servos to lower the gates. We have a sound player that we’ll be unveiling in December that could also be tied in to play any bell of your choice. (The player takes a microSD card, and you can put any WAV file on it you’d like to play.) The only part that leaves out is the actual flasher circuit, and for that I don’t necessarily have a solution. There are a number of flasher circuits available commercially, such as the Circuitron FL-2, that should be compatible, or Rob Paisley’s website has a number of good flasher circuits if you feel up to building your own.

      Parts cost would be highly variable depending on exactly what you chose. At a minimum, you’re looking at 4x CKT-IRSENSE, 1x MRServo-1, 1x MRServo crossover kit (to get you the Y cable and second servo for the second gate), some sort of flasher, and the audio player. The IR sensors and the servos/driver board would be $107, and our standard international priority mail shipping is $30 to Australia. We haven’t actually finalized the pricing on the audio player – it’s one of the few things we have to yet finish before its release.

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